Intermittent high / fast idle?
Lester Burnham
Recently acquired Kia Carens (first registered December 03) 1.8 petrol
- hey it was cheap and it's very practical. 60k miles on the clock,
looks quite well looked after. Serviced well, and oil and other fluids
recent, and look to be at the correct level(s). I had the cambelt and
tensioner changed a few days back.
I have an issue with idle speed being quite high when the car is hot.
When cold, idle seems correct, a little over 1k revs, then gently
drops to somewhere (at a guess around the 800-900rpm point) as it
gently warms up. But when it's been driven for a bit (I notice it
most, because I mainly do motorway journeys) after being driven for a
while, when it's fully warmed up, then when stopping, the idle speed
can be around 1600-1700 revs, sometimes slightly increasing to 2k.
Blipping the throttle when it's behaving like that, and revs can stay
high at 3k or 4k revs.
No warning lights on (and yes, they all work - light up, then go out
when turning on and starting). Later on in journeys, it may have
sorted itself out, or if it's been behaving like that, and I've
stopped somewhere, got out, then got in again a minute or two later,
and start, and it behaves normally - eg this morning - drove about 5
miles to take my youngest to nursery. Car was reasonably well warmed
up, by the time I got there, the idle had gone high, took him in (must
have been all of 2 or 3 minutes) then got in and started, and it idled
where you'd expect when warm (around 800-900rpm).
My initial thoughts were that it's unlikely to be an induction leak,
because surely it would do that all the time when hot - and although
the frequency of it behaving like this, does seem to be on the
increase, there are times when it doesn't do it, or when (over a
longer journey) it might have been doing it, but later on in the same
journey it's returned to behaving normally.
Which leaves me to think an intermittent problem like this could be
some sensor?
Or - and what I thought I'd try and have a look at today some time -
sticking / dirty throttle plate, or IACV / ICV playing up. I think the
throttle must be electronically controlled, because a quick perusal
and I can't make out any cable from the bulkhead going to it. I
thought I'd try and give the throttle plate / body a good clean, and
if possible, same with the IACV (I've had other cars, where idle
issues - especially when hot - were caused by the IACV).
Anybody any ideas or clues - likely to be electronic, or perhaps
throttle / idle valve?
As an aside - assuming I'm right about the throttle being electronic,
and I'm sure I've read these engines have IACVs / ICVs - I think I've
spied it, anyway, to the rear of the throttle body - why do they need
IACVs / ICVs if the throttle is electronically controlled?
Mrcheerful
iacv is the likely fault, under larger throttle openings they open, when
throttle is released they should close, but if they are dirty then they can
stick open or close very slowly. The long term cure is to run on good
petrol and oil (and change it regularly) To prove it is the iacv just
disconnect it and take it for a drive, you may well have warning lights and
it may not idle, but if the 3 - 4 k revving is gone then it is very likely
the iacv , next would be remove and clean it or replace it, depending on
ease of access and cost.
Lester Burnham
> iacv is the likely fault, under larger throttle openings they open, when
> throttle is released they should close, but if they are dirty then they can
> stick open or close very slowly. The long term cure is to run on good
> petrol and oil (and change it regularly) To prove it is the iacv just
> disconnect it and take it for a drive, you may well have warning lights and
> it may not idle, but if the 3 - 4 k revving is gone then it is very likely
> the iacv , next would be remove and clean it or replace it, depending on
> ease of access and cost.
Thanks for that.
I've sorted issues before with IACVs on other cars - and actually found that once either cleaned up, or replaced, I didn't have a repeat of the problems, I tend to drive 50 or 60 miles at a time, so always used to find that once cleaned or replaced they largely stayed clean (same with the throttle body).
I did find on one Volvo (S70) that when the IACV was playing up, and / or unplugged, warm / hot idle was high.
I'll try and give it all a good clean today. I'll also try and unplug the IACV if I can get it to idle hot again, and see if that shows a difference.
Thanks again.
Dave Plowman (News)
<fb90452f-ee51-4ddd...@h17g2000yqn.googlegroups.com>,
Lester Burnham <lester.o...@gmail.com> wrote:
> I have an issue with idle speed being quite high when the car is hot.
> When cold, idle seems correct, a little over 1k revs, then gently
> drops to somewhere (at a guess around the 800-900rpm point) as it
> gently warms up. But when it's been driven for a bit (I notice it
> most, because I mainly do motorway journeys) after being driven for a
> while, when it's fully warmed up, then when stopping, the idle speed
> can be around 1600-1700 revs, sometimes slightly increasing to 2k.
> Blipping the throttle when it's behaving like that, and revs can stay
> high at 3k or 4k revs.
Likely a problem with the ICV. (Idle control valve). They are commonly a
stepper motor moving a valve, controlled by the ECU. Removing and cleaning
can often work.
--
*Money isn't everything, but it sure keeps the kids in touch *
Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.
Lester Burnham
I was wrong about the type of throttle - it isn't electronically actuated, it does have a cable, it just wasn't that obvious from my first looks. I removed the induction trunking to the throttle body - have to say, the throttle body and plate looked quite clean.
The IACV was where I thought it was, bolted to the rear / firewall side of the throttle body. I removed it and gave it a good clean with carb cleaner. Looked a bit black inside, but not as filthy as I imagined it to be. Took a bit of cleaning with some cotton buds, to get the metal flap and other areas as clean as I'd like. As with other IACVs, when I'd finished cleaning it, I could feel the flap move a bit inside, when I swung the IACV - so seems to be moving freely as it should.
Put it all back together and ran the car up to temperature (parked up, mind, not driving) and the idle speed behaved perfectly, but then I'm not so sure it wouldn't have done the same prior to cleaning it. Even when warm, blipping the throttle had no lag or hesitation about the idle returning to where it should be.
Road testing and general driving should give more of a clue as to whether that's done the trick.
If it still plays up, I'll unplug it, see what difference that makes.
Thanks for the help, chaps.
Mrcheerful
it would behave while stationary as the opening is only done in response to
throttle opening combined with road speed.
Lester Burnham
again, when I got there, engine was warm, idle about 2k revs. With the
engine on, unplugged the IACV. Revs dropped a fair amount (at a guess
to about 1200-1300rpm - experience with iffy IACVs in the past tells
me that tends to be where the engine idles at, when warm, and IACV is
either broken or unplugged).
After that, switched off, took ankle biter in to nursery, then drove
another couple of miles, filled up with petrol. After that (ie turning
on after filling up) then check engine light came on - I'm guessing
that's almost certainly due to unplugging the IACV, and idle trim
being out of bounds? I'm ever hopeful, that the Kia's engine software
is one of those that doesn't need the light turning off with a
specific tool / gadget (some cars, seem to right themselves where
check engine lights are concerned, when it's been fixed, and several
ignition cycles have been done, others, though, seem to require a
software device to reset it).
Drove about 60 miles, then, car behaved as expected, warm idle
1200-1300rpm (as I'd expect with the IACV unplugged) but no issues
when blipping the throttle, idle returns to it's previous point.
During the day, I've left the plug connected - to avoid any moisture
ingress into the connections. I suspect if unplugged when started from
cold, idle will be a bit too low (from what I've experienced in the
past, 400-600rpms with a broken / disconnected IACV).
So I'm going to source a replacement, should be able to muddle through
with it until then. Conveniently, you can read the part number on the
IACV with it all connected up. What I'm wondering is, whether the
crafty Kia people did that simple out of cleverness, pure dumb luck,
or because the IACVs they use have a propensity for failure.
Thanks for the advice, chaps, will probably update the thread once
I've put on a new IACV, just to confirm / deny it's properly cured the
issue.
Dave Plowman (News)
<4b019822-87dc-4abf...@q15g2000yqk.googlegroups.com>,
Lester Burnham <lester.o...@gmail.com> wrote:
> So I'm going to source a replacement, should be able to muddle through
> with it until then. Conveniently, you can read the part number on the
> IACV with it all connected up. What I'm wondering is, whether the
> crafty Kia people did that simple out of cleverness, pure dumb luck,
> or because the IACVs they use have a propensity for failure.
Generally, they are not the most reliable of devices. The ones used on the
Range Rover with the old Rover V8 are a constant source of problems.
--
*The longest recorded flightof a chicken is thirteen seconds *
Lester Burnham
Not meaning to mither, but it may be of some use to somebody else...
I drove around for a couple of journeys with the IACV unplugged
(although plugged it in when stopped, to try and avoid any moisture
ingress). Truth be told, it didn't seem a world away from where it
should be - most noticably, the idle speed was consistent, but higher
than it should be (at a guess around the 1200rpm mark). That was the
same whether the engine was warm or cold (I started it up, after being
left around 8 hours, parked up) and the cold idle was at this point
(but remained at that point). No issue with blipping the throttle
leaving the revs high, though. As I mentioned in my previous post,
after about 3 cycles of the ignition, with it unplugged, the check
engine light came on.
I bought an aftermarket IACV (was just shy of £50 - Kia dealers wanted
around £150, and other sites selling OEM spec ones seemed to be in
that order).
Looking at it, and inside at the workings (from what you can see down
the tubes) it looks identical to the OEM one I took off. Design looks
identical, markings look identical, I supposed the gubbins inside
might be of inferior quality, but doesn't look to be from the outside.
Anyway, I've put this new one on the car, and it behaves perfectly as
it should do - but only tested with the car stationary. After 3 cycles
of ignition, the check-engine light went out - so yay on that score.
I'll probably post one more update as to whether it's truly fixed the
problem when I've had chance to drive it properly, and get the engine
fully warm.
Duncan Wood
Thankyou.
Lester Burnham
Not quite as positive as I'd hoped. For 3 or 4 days I thought I'd got
it sorted - with a replacement IACV (new, but pattern part). Over
mainly distance journeys (around 60 miles at a time) and some shorter
journeys, it behaved perfectly with the new IACV, when it would have
definitely showed behaviour as before replacing the IACV.
But today was a different story - quite a warm day, just short
journeys, with the kids, mile or two at a time, often with the air-con
on a lot. It happened again - revs creeping up to around 2k when
idling and stationary - and it sort of creeps up there, too. Any blip
on the throttle would make the idle rise to, say, 3k revs and stay
there.
One other thing I noticed, when it's doing this - say stopped at
traffic lights or at a junction, when it's idling high like this,
switching on the air-con brings the idle down to about 1k revs - which
seems a lot of change, accepting that an air-con compressor is a far
amount of drag on the engine.
One other factor - one of the drive / auxiliary belts must slip at
times - most noticable at low engine speeds, with the air-con on. I've
not noticed the battery / alternator light flickering when it's doing
it, though. I'll have to get that sorted, it's nagging at me that it's
in some way related.
So I'm left with the following possibilities:-
1. Original IACV was bad, new one has gone bad in a short number of
days - a possibility. I'm pretty sure that when it's revving high, if
I unplug the IACV, the creep / rise in idle revs to 2k, won't happen,
so it's clearly related.
2. Some condition of the engine, is making the IACVs go bad.
Everything seems OK, otherwise, no oil consumption, fuel consumption
seems about right. When I'd looked at the throttle plate / body, it
was cleaner that I'd expected - truth be told, the trunking to the
throttle body, and the clip and bolt looked like they'd never been
apart or unfastened - so I expect nobody had ever had it apart before
I did.
3. Some condition, fault, or problem is making the ECU tell the IACV
to behave this way. Seems odd, and unlikely, but if it's the IACV
that's making the engine race when it should be idling (and unplugging
it when it's doing this, and seeing the revs drop to where I'd expect,
were the IACV not operating implies that), and there's a certain
degree of unlikelihood that a new replacement IACV is either broken in
less than a week, or made bad by some condition of the engine - then I
have to at least accept the possibility.
4. Some other fault / problem / issue is causing this behaviour, and
unplugging the IACV when it's doing it, stops it, but masks the true
cause - dunno how plausible that is.
There's no check engine light on, or any other warning lights on - and
they all seem to work correctly - come on when the ignition is turned
on, go off when the engine is started. Nor is there any behaviour or
condition of the engine I can look at that seems overtly wrong - with
the exception that I can hear one of the belts slipping at times, at
low engine speeds, especially with the air-con on.
I think the next course of action will have to be unplugging the IACV
for the moment - it's more tolerable to have a permanently slightly
higher idle, than one that is far too high when the engine is hot.
This will no doubt, put the check engine light on, like last time,
which went away, after installing the new IACV, plugging it in, and 3
cycles of the ignition / engine start.
After that, I think I should probably buy one of those cheap code
readers / erasers, plug in the IACV, clear any codes, drive it, see
what happens, hopefully it will do it again, and read the codes.
In the meantime, any thoughts, ideas or suggestions welcome!
And I was so sure it was fixed, too.
Duncan Wood
Small airleak somewhere?
Lester Burnham
news:op.vzawj...@duncan-tosh.netgear.com...
>
> Small airleak somewhere?
I wondered about an air leak, but thought if that were the case I could
expect the problem permanently, even when cold?
There are times when it takes provocation to do it. Yesterday, I ran with
the IACV unplugged - thinking it was the problem again, and found with it
unplugged the first time, the car was much less problematic. What I found,
though, made me reconsider the IACV as being the fault, and merely
contributing to it when it happens.
I had two journeys of around 60 miles to do (home -> office -> home) -
mostly motorways, and a couple of small journeys at both home ends. I
noticed, part way through the morning motorway run, that the idle was higher
than I would have expected (this is all with the IACV unplugged) - blipping
the throttle doesn't seem to affect it with the IACV unplugged - but again,
turning on the air-con, drags the idle speed down to about 1k revs.
So I'm guessing the hot idle rising is independent of the IACV, and perhaps
with the IACV connected, the only issue being that throttle blips when
idling, can push the idle up further.
Anyway, when I'd driven back to my home town, and had to collect my son on
the way back home (by this point, I'd have driven a little over 60 miles),
the car was idling around 1700-2000rpms, IACV was unplugged, I parked up,
nipped in to my parents to collect my son - would have been in their house
2-3 minutes, no more than 5, so the car would have still been warm. Got in,
started, car idled about 1k revs (IACV still unplugged - I suspect had it
been plugged in at that point, idle would have been at the normal
800-900rpms). I then drove a short distance to my house, parked, left the
engine running, and opened the bonnet - it would have been idling about
1700-2000rpms at that point. I tried unplugging the MAF (wondering whether
that's what was causing this - and I'd read that often, unplugging it when
engines are playing up, and it having no effect, is kind of suggesting it's
knackered) - that seemed to make the revs rise ever-so-slightly.
So I then plugged in the IACV, and the revs dropped to a completely normal
level (I suspect around 800-900).
Before doing that, I was inclined to think maybe cleaning the MAF (it's a
Bosch MAF, from memory, similar is used on several cars / engines - in the
trunking betwixt airbox and throttle body) - I'd read that being very
gentle, and spraying on a little carb cleaner and letting it evaporate off,
can often clean the thin wire.
Now, though, and I think I'm going to be more cautious and not throw parts
at it. I've ordered a cheapo, generic code reader, I plan on resetting /
clearing all codes, and / or leaving the battery disconnected for a bit,
connecting it up, plugging in the IACV, then driving it as normal, and
waiting for it to play up, then seeing what the code reader says.
I'm partly wondering whether there's some odd adaptation going on, here, and
being confused at times with the IACV being unplugged (definitely brings on
the check-engine light). But still, there could well be some real problem,
here, and I'm just a bit puzzled with it.
Any of what I've written sound daft, or is there any other approach anybody
would recommend (and yes, I have considered just taking it to a dealers /
garage to sort out, but experience has shown me - especially with main
dealers - that with problems that are either intermittent, or dependent on
temperature, they can be quite ineffectual, time-consuming, and
inconvenient - in terms of having to get the car there, and often not having
a courtesy car to give you - albeit at short notice)?
And sorry to mither and go on about it, but I'd love to be able to have
sorted - or at least diagnosed this.
Duncan Wood
<lester.o...@gmail.com> wrote:
> "Duncan Wood" <nnt...@dmx512.co.uk> wrote in message
> news:op.vzawj...@duncan-tosh.netgear.com...
>>
>> Small airleak somewhere?
>
> I wondered about an air leak, but thought if that were the case I could
> expect the problem permanently, even when cold?
>
It'll still be there but the IACV will br almost closed instead of open
when the engine's cold.
Lester Burnham
> On Fri, 29 Jul 2011 08:44:58 +0100, Lester Burnham
> <lester.o...@gmail.com> wrote:
>
>> "Duncan Wood" <nnt...@dmx512.co.uk> wrote in message
>> news:op.vzawj...@duncan-tosh.netgear.com...
>>>
>>> Small airleak somewhere?
>>
>> I wondered about an air leak, but thought if that were the case I could
>> expect the problem permanently, even when cold?
>
> It'll still be there but the IACV will br almost closed instead of open
> when the engine's cold.
Would you expect a check engine light, at some point, though, with an air
leak? 'cos surely if it's unmetered enough to disrupt warm idling, it's
enough (over time) to trigger some condition. That said, reading the codes
may be much more revealling.
The only thing that seems to bring on the check engine light at present, is
leaving the IACV unplugged for 3 cycles of the ignition / engine start.
Reconnecting it, and 3 cycles later, it goes out.
What's swaying me away from induction air leak, being that it only seems to
be certain conditions triggering this. Today I just drove a shortish
journey - and I've kept the IACV plugged in, now - the car temperature gauge
got fully into the normal bit, and the IACV responded to bring the idle down
from cold (little over 1k revs) to normal warm idle (800-900) and I drove
for a few miles, locally, and had no issues.
I would have thought an induction leak would have meant it would behave the
same any time the temperature got to the point where the IACV is bringing
the idle down to warm / hot engine speeds - but that's not necessarily
happening - and as I mentioned from my use, yesterday, after an hour, or so,
driving, stopped for a couple of minutes, when I started again it idled
perfectly 'til I'd been driving for a minute or so.
I guess if nothing else, one thing I've found is initially thinking it was
the IACV, it seems to behave like this with it disconnected. Roll on the
fault code reader arriving.
And thanks for your suggestions - anything making me think over it is help,
and I'd really love to crack this nut.
tony sayer
>same any time the temperature got to the point where the IACV is bringing
>the idle down to warm / hot engine speeds - but that's not necessarily
>happening - and as I mentioned from my use, yesterday, after an hour, or so,
>driving, stopped for a couple of minutes, when I started again it idled
>perfectly 'til I'd been driving for a minute or so.
>
>I guess if nothing else, one thing I've found is initially thinking it was
>the IACV, it seems to behave like this with it disconnected. Roll on the
>fault code reader arriving.
>
>And thanks for your suggestions - anything making me think over it is help,
>and I'd really love to crack this nut.
>
>
Me too!, my olde Audisaursus has an almost identical fault thats more
annoying that anything else. Its doing almost the same thing odd in that
when its in fault mode the revs will go from 850 odd to 1500 as if your
blipping the throttle. If you should rapidly switch the ignition on and
off it more often than not settles down to 820 rpm till you put your
foot on the go pedal when its off again.
IACV changed original was duff so I reckon theres another part faulty
somewhere MAF seems clean must get around to checking some resistance
readings. It is much worse when hot, both temp sensors changed, almost
behaves itself when cold from start..
--
Tony Sayer
Lester Burnham
news:wX0PLOGY...@bancom.co.uk...
Have to say, I'm wondering about coolant temperature sensor. But then I
don't want to blindly go buying parts - but it does seem at least as if it
may be relevant. I just would have thought I'd get an engine light. I think
the fault code reader, when it arrived, may shine more light on it.
Oddly enough, in other cars I've had, I've had check engine lights come on -
or at least definite symptoms - for bad sensors - but in those cars, no
warning lights from either bad, or disconnected IACVs.
Like yours, mine is fine from cold, and often (for short periods) fine when
warm or hot. But when it starts happening, it doesn't yo-yo, if you slow
down to stop, the revs may naturally fall to somewhere, say 1300-1500 revs,
before declutching. Then when stopped, either in neutral, or in gear,
waiting to move, with the clutch down, the revs stay at that point, and
progressively rise to settle at around 2k. Air-con compressor being turned
on, drags it down to around 1k, if I turned it off, the revs would rise to
about 2k again. With the IACV connected, blipping the throttle would see the
revs stick at their highest point. Blipping the throttle with the IACV
unplugged, has the revs rise a bit, then drop down to about 2k.
And also like you, turning off the car, then restarting it can often see it
behave normally - at least until driving around a bit.
Thanks for replying, the info is all sinking in.
Lester Burnham
comments, now, from web links suggesting an alternator issue for these
symptoms. One was unqualified, the other in relation to a 2005 Mini, and
said that the ECU had detected low voltage from the alternator, and decided
to up the revs.
Does that sound tenable?
I mentioned, previously, that occasionally I can hear one of the drive belts
slipping (tends to only really be noticable when the air-con is turned on),
so I suppose that could be contributory.
If it was the alternator, should I expect to see any flickering or blinking
of the battery warning light? Or failing that, would a fault code likely be
logged?
Also worth noting, once when this problem occurred, I'd just left on
motorway, and was waiting at a junction on a roundabout to join another.
This would probably be when I'd first really noticed it. So I was
stationary, the car was revving away at about 2k revs, I'd blipped the
throttle and the revs had risen to 3k. Not wanting to sit there for a while,
waiting for the lights, with the engine blazing away at 3k, I turned off -
that may not have been the best thing to do, but it didn't seem good to sit
there with it running at 3k revs, either. Then I struggled to start it
again. But it didn't turn over and fail to fire, it just didn't turn over. I
was stuck for a couple of minutes like that, with my hazards on, and people
having to drive around me, expecting I'd have to call out breakdown cover,
when I tried again, it turned slowly, then started. Slightly before that,
I'd noticed a little smoke from the side of the bonnet. After that, I drove
to my destination, everything seem fine, when I got there, I had a look
under the bonnet, and could see no rhyme or reason for the trace of smoke I
saw.
Needless to say, ever since, whenever I've had it rev like that in traffic,
I've never turned it off, I've always managed it some other way.
Duncan Wood
<lester.o...@gmail.com> wrote:
> "Duncan Wood" <nnt...@dmx512.co.uk> wrote in message
> news:op.vzdjx...@duncan-tosh.netgear.com...
>> On Fri, 29 Jul 2011 08:44:58 +0100, Lester Burnham
>> <lester.o...@gmail.com> wrote:
>>
>>> "Duncan Wood" <nnt...@dmx512.co.uk> wrote in message
>>> news:op.vzawj...@duncan-tosh.netgear.com...
>>>>
>>>> Small airleak somewhere?
>>>
>>> I wondered about an air leak, but thought if that were the case I could
>>> expect the problem permanently, even when cold?
>>
>> It'll still be there but the IACV will br almost closed instead of open
>> when the engine's cold.
>
> Would you expect a check engine light, at some point, though, with an air
> leak? 'cos surely if it's unmetered enough to disrupt warm idling, it's
> enough (over time) to trigger some condition. That said, reading the
> codes
> may be much more revealling.
No idea on that car, looking `at the live readings would be revealing.
Has it got the irritating VAG failure mode where the engine management
temperature sensor is completely seperate to the dashboard one?
Lester Burnham
> Has it got the irritating VAG failure mode where the engine management
> temperature sensor is completely seperate to the dashboard one?
Not sure about that until I look into it more. The temperature gauge seems
to behave normally, and settles in the region that other owners say is
normal (always stays a little below halfway - I'd normally think that was
suggestive of the thermostat needing replacing - but it appears to be normal
for the model).
Just seemed to be frequently mentioned as the fault for plenty of similar
symptoms, from googling it (CTS, that is). That said, so is the TPS. I think
when I experience it happening again (still awaiting the fault code reader),
and I've got an opportune moment to stop, I'll see what unplugging the CTS
and TPS does to the idle behaviour.
Lester Burnham
I'm wary this could turn into a blog-like-epic, but all the same, thought
I'd post my latest findings - to see if anybody with a sharper brain can
illuminate me.
So I'd replaced the IACV, with a pattern part, that didn't seem to cure the
problem.
Further cleaning of the throttle body seemed to have a positive effect - in
fact, I don't think I've had any instances when it's happened and blipping
the throttle has pushed the idle any higher.
Before my code reader arrived, but after I'd had an abortive attempt at
changing the CTS (speculatively bought a new one, as there's a Kia
dealership literally 5 minutes from where I live) I'd done some more
cleaning of the throttle body, as I'd had it all apart to try and get better
access to change the CTS. I also adjusted / checked the throttle cable, and
made sure the linkage and spring were all clean and moving freely. So rather
than disconnect the battery (to reset the ECU - I wanted to have a clean-ish
slate for when I code properly read the codes) - didn't particularly want
the rigmarole of having to set the clock and the radio... - I noticed the
fusebox has a dedicated fuse for the ECU, so I took the fuse out for a few
hours.
After that, things seem to improve quite a bit, really, no real instances of
it happening for a couple of days, and when it did occur, it wasn't that
bad - about 1500rpms, blipping the throttle didn't push it any higher,
turning on the air-con would make it drop right down, and in many instances,
it just didn't do it.
At this point, my code reader arrived - worked perfectly, no codes stored,
no reported issues displayed.
Any way, having that problem where you just can stop tinkering, realising I
hadn't done as thorough job cleaning the throttle body as I'd liked - and
after all the problem hadn't totally gone away - I thought I'd give it one
more go, with an old toothbrush - working on the premise that things seemed
to have improved since doing so in the previous instance.
That didn't seem to make any difference in the short term. However,
yesterday, during my second 60-ish mile journey in it, the rev problem came
back with a vengeance. When hot, and, say, leaving one motorway, stopping at
lights / junctions, revs would stay at 1500rpms (minimum) and steadily
climb - I think if I'd have left it to, probably to the rev limiter, because
in a couple of instances it had got to 3k revs and was still going. Turning
on the air-con - especially when just stopped / just as the revs started
climbing could see it halt progress, and if timed well, drop down to 1k
revs, but when the revs had already climbed to about 3k, it had limited
effect. Also, when the revs were high, and I hadn't been that quick getting
the air-con turned on, or it took a second or two for the ECU to turn on the
compressor, selecting first, and gently taking up the bite to move the car
(not leaving the clutch wearing away, though) was enough loading to drag the
revs down.
When I got a chance to stop, I plugged in the code reader - but still
nothing - no codes, and nothing else within the diagnostics on it, to point
to anything.
When I'd finally stopped, I looked to see the throttle linkage and spring
position, the throttle didn't look to be stuck open.
So now I'm puzzled, I guess the only thing that could have the revs climbing
like that - assuming the throttle is closed, linkage and cable not sticking,
is the IACV. I can't believe the IACV has gone bad, so can only think it's
doing this under instruction from the ECU. The IACV doesn't seem to be
sticking - because when stopped, revs can be around 1500, then start
climbing. Plus I haven't seen the return of blipping the throttle pushing
the revs higher, when it's happening. Although, truth be told, the revs are
creeping higher all by itself.
Vacuum leak has been mentioned, but would it keep climbing like this (3k, 4k
probably higher revs, if left to it's own devices) - but not
comprehensively - if I was just parked up, turned on, let it warm slowly at
idle, it would probably not do this. And wouldn't I likely see some error
codes from such a significant induction leak?
Next plan of action is to await delivery of one of those USB ECU live data
thingmies (ELM?) and run the software on a laptop and plug it in when it's
behaving like this, and see what all the live data monitor-ables show -
maybe that might give some clue as to what's getting the engine to behave
like this.
Do the current symptoms make any sense to anybody - any other advice? And
yes, I'm rapidly approaching the whole take it to a dealers and let them
sort it out - but, dammit, for my own sanity I'd just like to understand,
and even fix it myself.
Dave Plowman (News)
a good old physical problem. Like as you said an air etc leak. Assuming
the ICV is operating correctly.
--
*Of course I'm against sin; I'm against anything that I'm too old to enjoy.
tony sayer
<lester.o...@gmail.com> scribeth thus
>Further update!
>
>
>I'm wary this could turn into a blog-like-epic, but all the same, thought
>I'd post my latest findings -
Not at all..
>So I'd replaced the IACV, with a pattern part, that didn't seem to cure the
>problem.
>
Snipped a tad..
>
>Do the current symptoms make any sense to anybody - any other advice? And
>yes, I'm rapidly approaching the whole take it to a dealers and let them
>sort it out - but, dammit, for my own sanity I'd just like to understand,
>and even fix it myself.
>
>
Only thing that -seems- it has much to do with it is elevated
temperature. I've got an almost identical problem on the Audisaurus and
when it was hot the other day it was almost up to 2000 RPM on idle and
would not respond to the quick flick on and off of the ignition switch
which clams it down to 800 odd..
I too have a replacement pattern e-bay idle valve and I sometimes wonder
if that might be the cause..
I'm minded to clean out the original which was causing stalling and see
if thats any different..
--
Tony Sayer
Lester Burnham
>
> Only thing that -seems- it has much to do with it is elevated
> temperature. I've got an almost identical problem on the Audisaurus and
> when it was hot the other day it was almost up to 2000 RPM on idle and
> would not respond to the quick flick on and off of the ignition switch
> which clams it down to 800 odd..
It does seem temperature related - and seems to be when the engine has got
truly warm from running / driving a while, rather than just showing normal
coolant temperature.
Turning off, then on, doesn't seem to help mine.
> I too have a replacement pattern e-bay idle valve and I sometimes wonder
> if that might be the cause..
>
> I'm minded to clean out the original which was causing stalling and see
> if thats any different..
After a while of using the new one, I did wonder whether there was anything
wrong with my original - at least anything other than needing a good clean.
I've not had any repeated instances of blipping the throttle driving the
high idle even higher - I sort of attributed that to issues with the IACV.
Lester Burnham
news:51fdeee...@davenoise.co.uk...
>I wouldn't place my faith on some software solution. It sounds to me like
> a good old physical problem. Like as you said an air etc leak. Assuming
> the ICV is operating correctly.
I suspect you're right about where the problem is. The only thing I was
thinking about, software wise, was that it may give me some clues as to
what's going on when it does this.
The past couple of instances, there's not been the time to unplug the IACV,
either I've been driving in places difficult to stop, and / or the revs have
gone up to high, I was more worried about driving them down somehow.
As I mentioned in my reply to Tony, I think there might have been a minor
problem with the IACV at one point - the blipping of the throttle when the
idle was high, driving it even higher - which now doesn't happen.
In terms of an air leak, is spraying carb cleaner around vacuum lines a
reasonably safe approach?
Rob
ingested causing other problems - its a savage solvent.
Oil is a good substitute or WD40.
Dave Plowman (News)
Lester Burnham <lester.o...@gmail.com> wrote:
> >I wouldn't place my faith on some software solution. It sounds to me like
> > a good old physical problem. Like as you said an air etc leak. Assuming
> > the ICV is operating correctly.
> I suspect you're right about where the problem is. The only thing I was
> thinking about, software wise, was that it may give me some clues as to
> what's going on when it does this.
Diagnostic software can only help where it has the data to diagnose. The
ICV, for example, doesn't supply any such data.
--
*When companies ship Styrofoam, what do they pack it in? *
Lester Burnham
> In article <H5S_p.147315$w86....@newsfe22.ams2>,
> Lester Burnham <lester.o...@gmail.com> wrote:
>> >I wouldn't place my faith on some software solution. It sounds to me
>> >like
>> > a good old physical problem. Like as you said an air etc leak. Assuming
>> > the ICV is operating correctly.
>
>> I suspect you're right about where the problem is. The only thing I was
>> thinking about, software wise, was that it may give me some clues as to
>> what's going on when it does this.
>
> Diagnostic software can only help where it has the data to diagnose. The
> ICV, for example, doesn't supply any such data.
FPWM.
This car's ECU can at least detect when it's disconnected, though - whether
that's purely electrical (don't think so based on the symptoms) or perhaps
affect on long term idle trim - with the IACV disconnected, the check engine
light came on after 2 cycles of the engine running - reverse for plugging it
back in.
Previously cars, where I've had to tinker, and at times unplug, the IACV,
and there's been no warning lights.
I think where I'm coming from with the diagnostic software, is it seems to
have a dashboard showing a fair few parameters - I was just hoping when it
exhibits the behaviour, something looks different (not necessarily fault
code producing, mind) to normal - and I think it allows some logging as well
as real-time display.
From where I'm sat, the idle going up can only be a few things, really:
sticking throttle / cable - should be physically visible, under the bonnet,
and wouldn't account for the idle now slowly, but steadily increasing; IACV
doing it - either because it's faulty, or because the ECU is telling it to;
fuelling being increased for some reason (iffy TPS, or CTS) - but would have
thought there should be error codes for that; induction leak - again would
have thought there should be error codes for that.
Given the lack of error codes, one thing that's been haunting me about this,
is somebody posting to a forum about the idle speed on a Mini (I assume the
current one, not the original one), and it being raised because the ECU was
seeing some issue with the alternator's output, and increasing idle to
compensate. In that scenario, would you either expect there to be fault
codes stored, or some other warning lights (battery?). I keep coming back to
think about this, because I'm wondering whether there would be any other
obvious symptoms, or software / codes evidence.
tony sayer
>is somebody posting to a forum about the idle speed on a Mini (I assume the
>current one, not the original one), and it being raised because the ECU was
>seeing some issue with the alternator's output,
Yeabut how would the ECU know what -load- was on the alternator?..
> and increasing idle to
>compensate. In that scenario, would you either expect there to be fault
>codes stored, or some other warning lights (battery?). I keep coming back to
>think about this, because I'm wondering whether there would be any other
>obvious symptoms, or software / codes evidence.
>
>
Err umm .. Firmware upgrade;-!...
--
Tony Sayer
Chris Whelan
[...]
> Yeabut how would the ECU know what -load- was on the alternator?..
It wouldn't need to:
Engine running?
System voltage low?
Up the idle rpm a bit until voltage is OK.
Chris
--
Remove prejudice to reply.
Lester Burnham
news:j1hn2t$6f3$1...@dont-email.me...
> On Fri, 05 Aug 2011 19:50:55 +0100, tony sayer wrote:
>
> [...]
>
>> Yeabut how would the ECU know what -load- was on the alternator?..
>
> It wouldn't need to:
>
> Engine running?
> System voltage low?
> Up the idle rpm a bit until voltage is OK.
Exactly - that's what I'm wondering about. And I do wonder whether anything
would get flagged as an error.
Would account for the symptoms - increasing idle, as the increased idle
seems to have got worse.
What I'm not sure about - because, largely, car electrics are still a bit of
a mystery to me - is whether heat - perhaps especially high under-bonnet
heat - could be a factor influencing how much the alternator was playing up.
I'm also wondering whether the OBD dongle and software, might at least give
me some indications, reporting stuff in real-time, both when the engine is
behaving normally, and when playing up.
Lester Burnham
I got a chance to plug in my newly acquired USB thingmy (ELM interface -
£13.95 from ebay, with some software - easyobd, I think it's called). Have
to say, it's been worth every penny.
So I took my laptop and interface out to the car, connected it all up
started the car. Idle was perhaps normal for cold, but didn't seem to drop,
in fact slowly rose and started to race at 3k and climbing.
I had the software connected, and could see quite a lot of parameters, and
inspect the output / readings of quite a few sensors. The coolant and air
temperature readings all seemed very plausible and valid (coolant temp
raising as you'd expect). Wasn't sure what to expect with some of the other
sensors (02 for example, and there was 2 readings - the first showed an
indication of running rich / lean - as did another reading on fuel trim).
There was readings for engine load (calculated), battery volts (presumably
however the ECU measures that) and "Absolute Throttle Position".
When it was playing up - ie revs climbing and racing - nothing looked
unusual, other than the revs - coolant temperature was rising as you'd
expect. "Battery volts" didn't show any particularl change (on all readings
and logs, seems to be somewhere between 13.9v and around 14.2v).
The one thing that struck me as slightly odd, from the very off (ie engine
start at truly cold - not been started for about 3 days) was that the
"Absolute Throttle Position" was ranging from somewhere above 7.0% to
9.something% - I wasn't sure what to make of that - either the variance, or
it being above 0%, given my foot was well away from the throttle pedal. When
the engine started to race, there wasn't any notable change in this value.
Blipping the throttle, at this point, just pushed the revs higher. So I
disconnected the IACV. Absolute Throttle Position value went to 0%, and then
there was a code pending - no active code, mind, nor any MIL.
Monitored it like that for a while, and it largely behaved like it had done
in other instances of disconnecting the IACV (ie just electrically by
removing the plug). Looking at other measurements, the engine ran richer at
this point (ie with the IACV unplugged).
After a bit, I wondered what would happen if I plugged it in again - would
the engine start to race, or would it just settle. So I did - idle dropped
to somewhere in the normal region (a little over 900). And stayed like that.
And Absolute Throttle Position remained at 0%. Engine behaved perfectly,
even in response to blipping the throttle.
Thinking that I'd only termporarily "tricked" the ECU into thinking
everything was OK, I saved the current log of readings. And turned of the
car. I started it again, switched on the software to watch all the
parameters (it would be pretty much well warm by this point), again idle in
normal(ish) range (a little over 900 - I perhaps would have expected around
the 850 mark, but 900 and a bit is considerably more normal than 1500 rising
to 2k and beyond), absolute throttle position still 0%, calculated engine
load perhaps lower than previously.
Not wanting this to be a fluke, I saved the current log of readings, then
turned off. Gave it a few seconds, then turned it on again, and started
monitoring - exactly the same - pretty normal idling (low 900s), absolute
throttle position still 0% and unchanging unless I moved the throttle pedal,
everything looking normal, no problems, no pending codes, everything looked
(as far as I could see) normal.
A few hours later, I drove the car for a fair while, some local movements,
then a reasonable run of around 30 minutes. Everything seemed to behave as
normal - no high idle, no issues at all that I could see. After being parked
up for a couple of hours, made a return journey of about 30 minutes - same
again, everything seemed normal and fine.
So concluding from that, I could only think that some learning of the idle
was needed by the ECU (after all, I'd reset it a few times by either
removing the ECU fuse, or by doing so with my code reader) which makes me
wonder, could it possibly be a required step to plug in the IACV (or a new
one) after letting the car idle a bit, and then idle trim is established?
That's how it looked from monitoring it, and it's behaviour for the rest of
the day. Any comments or feedback on that theory welcome - either way.
Problem is, that sounds a little strange to me, and I've had instances where
I thought it had all gone away / been fixed, only for it to return with a
vengance some days later.
Still, at least I have something of a trick that seems to keep it running
fine for a while, if it happens again.
Thanks for your patience, if you're still reading this!
Dave Plowman (News)
Lester Burnham <lester.o...@gmail.com> wrote:
> I had the software connected, and could see quite a lot of parameters,
> and inspect the output / readings of quite a few sensors. The coolant
> and air temperature readings all seemed very plausible and valid
> (coolant temp raising as you'd expect). Wasn't sure what to expect with
> some of the other sensors (02 for example, and there was 2 readings -
> the first showed an indication of running rich / lean - as did another
> reading on fuel trim).
You can't get an indication of anything other than the correct mixture
with the engine hot. That's all a narrow band lambda sensor can tell you.
And the mixture will be rich while the engine is warming up.
--
*Time is what keeps everything from happening at once.
Lester Burnham
> In article <ifC%p.117404$OV1....@newsfe29.ams2>,
> Lester Burnham <lester.o...@gmail.com> wrote:
>> I had the software connected, and could see quite a lot of parameters,
>> and inspect the output / readings of quite a few sensors. The coolant
>> and air temperature readings all seemed very plausible and valid
>> (coolant temp raising as you'd expect). Wasn't sure what to expect with
>> some of the other sensors (02 for example, and there was 2 readings -
>> the first showed an indication of running rich / lean - as did another
>> reading on fuel trim).
>
> You can't get an indication of anything other than the correct mixture
> with the engine hot. That's all a narrow band lambda sensor can tell you.
> And the mixture will be rich while the engine is warming up.
Well there was 2 different metrics - one of them was "Short Term Fuel Trim
Bank 1" which seemed to flip / flip between being lean and rich most of the
time - 'cept when the IACV was disconnected, then it seemed to show
consistently rich (the first O2 sensor seemed to largely be congruent with
this reading, too). When it was plugged back in again, it went back to being
largely lean, with the occasional flip / flop to rich.
I don't know how accurate the gizmo and / or software is, but it was just a
curious thing, really, unplugging the IACV definitely seemed to have a
bearing on it running rich. That said, other than being something to note of
interest, I don't think that particular finding adds much to either the
problem diagnosis, or resolution of it - but as it related to the IACV being
(electically and physically) present, I wasn't sure if it had any bearing.
tony sayer
entlworld.com> scribeth thus
>On Fri, 05 Aug 2011 19:50:55 +0100, tony sayer wrote:
>
>[...]
>
>> Yeabut how would the ECU know what -load- was on the alternator?..
>
>It wouldn't need to:
>
>Engine running?
>System voltage low?
>Up the idle rpm a bit until voltage is OK.
>
>Chris
>
Well measuring the volts might not be the most accurate method to
determine the load on the alternator the amps would be the way to go but
either way I somehow have doubts this is causing the problem
concerned;!.,..
--
Tony Sayer
tony sayer
>was needed by the ECU (after all, I'd reset it a few times by either
>removing the ECU fuse, or by doing so with my code reader) which makes me
>wonder, could it possibly be a required step to plug in the IACV (or a new
>one) after letting the car idle a bit, and then idle trim is established?
>
>That's how it looked from monitoring it, and it's behaviour for the rest of
>the day. Any comments or feedback on that theory welcome - either way.
>
>Problem is, that sounds a little strange to me, and I've had instances where
>I thought it had all gone away / been fixed, only for it to return with a
>vengance some days later.
>
>Still, at least I have something of a trick that seems to keep it running
>fine for a while, if it happens again.
>
>Thanks for your patience, if you're still reading this!
>
>
Its quite possible that you might have a duff joint somewhere around
that un plugging and re plugging the IACV lead may well be disturbing
which will be OK for a day or two or three or more. Such is the way of
modern electric's..
I have read about this ECU learning but it seems that the ECU might be
learning the wrong things..
Anyways I expect that a garage doing the same job might be finding this
just as awkward to fix except that its often very useful to have spares
around to swap out just in case you might have a duff new one, and I've
seen that in other applications more than the once;!...
Keep us all informed of progress!...
--
Tony Sayer
Chris Whelan
As I said, the system wouldn't *need* to know the "load" on the
alternator; it just wants to know that the battery is not discharging.
Pretty much all ECU's get voltage feedback anyway, so it's a trivial bit
of software to give added security.
Providing a feedback to the ECU giving the current in the charging system
would be expensive and pointless.
I also doubt that it's anything to do with the OP's problems, especially
as it's unclear as to whether has car has such a system.
Dave Plowman (News)
Chris Whelan <cawh...@prejudicentlworld.com> wrote:
> > Well measuring the volts might not be the most accurate method to
> > determine the load on the alternator the amps would be the way to go
> > but either way I somehow have doubts this is causing the problem
> > concerned;!.,..
> As I said, the system wouldn't *need* to know the "load" on the
> alternator; it just wants to know that the battery is not discharging.
> Pretty much all ECU's get voltage feedback anyway, so it's a trivial bit
> of software to give added security.
Given every ECU is connected to the car electrical system, it's fair to
say it will know the voltage. ;-)
Most ECUs will alter the injector opening time to compensate for a varying
12 volt supply.
> Providing a feedback to the ECU giving the current in the charging
> system would be expensive and pointless.
As IMHO is having the ECU control the alternator. It's quite capable of
doing so itself. As they have been doing since first introduced.
> I also doubt that it's anything to do with the OP's problems, especially
> as it's unclear as to whether has car has such a system.
--
*Before they invented drawing boards, what did they go back to?
Chris Whelan
[...]
> Given every ECU is connected to the car electrical system, it's fair to
> say it will know the voltage. ;-)
The fact that it is supplied by the car's system doesn't automatically
mean that it will "know" the voltage in the sense of being able to detect
what the actual voltage is.
> Most ECUs will alter the injector opening time to compensate for a
> varying 12 volt supply.
Indeed. By virtue of the trivial piece of s/w I mentioned.
>> Providing a feedback to the ECU giving the current in the charging
>> system would be expensive and pointless.
>
> As IMHO is having the ECU control the alternator. It's quite capable of
> doing so itself. As they have been doing since first introduced.
Are you saying that systems that have better control of battery charge by
using the ECU are not a good thing? If so, I'm afraid I disagree strongly.
Systems like Ford's Smart Charge have significantly improved battery
life, and likewise reduced the chances of being stranded with a flat
battery. Again, there is very little cost. Existing sensors are used for
things like temperature monitoring. There is one extra wire to the
alternator. The rest is done in software.
The actual regulation is still done in the alternator; you can remove the
single extra wire to the alternator and it will still charge.
What's not to like ;-)
Dave Plowman (News)
Chris Whelan <cawh...@prejudicentlworld.com> wrote:
> Are you saying that systems that have better control of battery charge
> by using the ECU are not a good thing?
Pointless. Except to tie you into Ford spare parts.
> If so, I'm afraid I disagree
> strongly.
> Systems like Ford's Smart Charge have significantly improved battery
> life, and likewise reduced the chances of being stranded with a flat
> battery.
The batteries on both my cars are over 7 years old. The one on the SD1 -=
which sometimes isn't used - has gone flat a few times too. It's a no name
far east one from the local accessory shop. The BMW one Bosch.
> Again, there is very little cost. Existing sensors are used for
> things like temperature monitoring. There is one extra wire to the
> alternator. The rest is done in software.
And as we all know software means perfect? ;-)
> The actual regulation is still done in the alternator; you can remove
> the single extra wire to the alternator and it will still charge.
All rather OTT for a simple lead acid battery.
--
*Strip mining prevents forest fires.
Chris Whelan
> In article <tSQ%p.108184$T85....@newsfe19.ams2>,
> Chris Whelan <cawh...@prejudicentlworld.com> wrote:
>> Are you saying that systems that have better control of battery charge
>> by using the ECU are not a good thing?
>
> Pointless. Except to tie you into Ford spare parts.
How does it do that? Many non-OEM alternators are available for my
Focus...
>> If so, I'm afraid I disagree strongly.
>
>> Systems like Ford's Smart Charge have significantly improved battery
>> life, and likewise reduced the chances of being stranded with a flat
>> battery.
>
> The batteries on both my cars are over 7 years old. The one on the SD1
> -= which sometimes isn't used - has gone flat a few times too. It's a no
> name far east one from the local accessory shop. The BMW one Bosch.
The battery on my last Focus was 10 years old, and still starting the car
in all conditions.
>> Again, there is very little cost. Existing sensors are used for things
>> like temperature monitoring. There is one extra wire to the alternator.
>> The rest is done in software.
>
> And as we all know software means perfect? ;-)
?
>> The actual regulation is still done in the alternator; you can remove
>> the single extra wire to the alternator and it will still charge.
>
> All rather OTT for a simple lead acid battery.
Absolutely not. Smart Charge is one of Ford's better ideas.
tony sayer
>On Mon, 08 Aug 2011 11:19:23 +0100, tony sayer wrote:
>
>> In article <j1hn2t$6f3$1...@dont-email.me>, Chris Whelan <cawhelan@prejudic
>> entlworld.com> scribeth thus
>>>On Fri, 05 Aug 2011 19:50:55 +0100, tony sayer wrote:
>>>
>>>[...]
>>>
>>>> Yeabut how would the ECU know what -load- was on the alternator?..
>>>
>>>It wouldn't need to:
>>>
>>>Engine running?
>>>System voltage low?
>>>Up the idle rpm a bit until voltage is OK.
>>>
>>>Chris
>>>
>>>
>> Well measuring the volts might not be the most accurate method to
>> determine the load on the alternator the amps would be the way to go but
>> either way I somehow have doubts this is causing the problem
>> concerned;!.,..
>
>As I said, the system wouldn't *need* to know the "load" on the
>alternator; it just wants to know that the battery is not discharging.
Well to do that it needs to know what is flowing where a simple single
point voltage measurement isn't really going to do that..
>Pretty much all ECU's get voltage feedback anyway, so it's a trivial bit
>of software to give added security.
>
>Providing a feedback to the ECU giving the current in the charging system
>would be expensive and pointless.
>
>I also doubt that it's anything to do with the OP's problems, especially
>as it's unclear as to whether has car has such a system.
No, agreed on that;!...
>
>Chris
>
--
Tony Sayer
Chris Whelan
[...]
>>As I said, the system wouldn't *need* to know the "load" on the
>>alternator; it just wants to know that the battery is not discharging.
>
> Well to do that it needs to know what is flowing where a simple single
> point voltage measurement isn't really going to do that..
How do you think that the state of charge of a battery can be determined
by the current flowing?
To use the infamous "tank of water" analogy, you couldn't determine how
much water was in the tank by measuring the flow rate out of it. (Unless
you knew the original volume, and calculated it, which is something else
altogether of course.)
Dave Plowman (News)
Chris Whelan <cawh...@prejudicentlworld.com> wrote:
> > Well to do that it needs to know what is flowing where a simple single
> > point voltage measurement isn't really going to do that..
> How do you think that the state of charge of a battery can be determined
> by the current flowing?
Assuming you know the external load, you can determine the battery state
by the current it draws while charging. Because the correct charger for
lead acid is constant voltage which varies the current as the battery
voltage changes while it charges.
--
*I couldn't repair your brakes, so I made your horn louder *
Chris Whelan
> In article <Dm50q.109130$29.4...@newsfe08.ams2>,
> Chris Whelan <cawh...@prejudicentlworld.com> wrote:
>> > Well to do that it needs to know what is flowing where a simple
>> > single point voltage measurement isn't really going to do that..
>
>> How do you think that the state of charge of a battery can be
>> determined by the current flowing?
>
> Assuming you know the external load, you can determine the battery state
> by the current it draws while charging. Because the correct charger for
> lead acid is constant voltage which varies the current as the battery
> voltage changes while it charges.
You can. For the purposes under discussion (raising idle speed to
maintain alternator output when the battery state is low), why would you?
Dave Plowman (News)
Chris Whelan <cawh...@prejudicentlworld.com> wrote:
> On Tue, 09 Aug 2011 10:07:42 +0100, Dave Plowman (News) wrote:
> > In article <Dm50q.109130$29.4...@newsfe08.ams2>,
> > Chris Whelan <cawh...@prejudicentlworld.com> wrote:
> >> > Well to do that it needs to know what is flowing where a simple
> >> > single point voltage measurement isn't really going to do that..
> >
> >> How do you think that the state of charge of a battery can be
> >> determined by the current flowing?
> >
> > Assuming you know the external load, you can determine the battery
> > state by the current it draws while charging. Because the correct
> > charger for lead acid is constant voltage which varies the current as
> > the battery voltage changes while it charges.
> You can. For the purposes under discussion (raising idle speed to
> maintain alternator output when the battery state is low), why would you?
Why would you want to raise the idle speed if the battery was low? Better
to fit a correctly specced alternator. It's not like as though modern cars
have a slow idle - quite the reverse.
--
*Strip mining prevents forest fires.
Dave Plowman da...@davenoise.co.uk London SW
Chris Whelan
[...]
> Why would you want to raise the idle speed if the battery was low?
> Better to fit a correctly specced alternator. It's not like as though
> modern cars have a slow idle - quite the reverse.
*I* wouldn't want to; if you'd read up-thread, you would see that's what
BMW do with the Mini...
tony sayer
<cawh...@prejudicentlworld.com> scribeth thus
In fact this isn't that simple to do that accurately is it?. You'd need
to know where a lot of currents are going to make it anywhere near
sensible i.e. what's coming off the alternator what's going to or coming
from the battery what's going into the cars electrical system..
It would seem that all you need to do in effect is to voltage and
current limit the alternator output. That is perhaps all thats really
required.
Unless you might need to know what the alternator is "pulling" off the
crankshaft in order to regulate the engine load, but then again if your
doing that you'd need to know what the water pump is doing 'tho that
seems like a constant load .. the steering pump and brake servos etc
hardly seems worth the bother..
The load pulled by a aircon pump is a significant one so some means of
measuring what thats taking is perhaps in order, how you'd do that is
interesting perhaps if the Aircon is ON then you'd add in "x" amount of
fuel mix extra for an assumed constant load..
--
Tony Sayer
Dave Plowman (News)
> [...]
I'd guess this is more to do with the engine start/stop system. Rather
than a general benefit.
--
*If you're not part of the solution, you're part of the precipitate *
Chris Whelan
[...]
>> *I* wouldn't want to; if you'd read up-thread, you would see that's
>> what BMW do with the Mini...
>
> I'd guess this is more to do with the engine start/stop system. Rather
> than a general benefit.
Thinking about it, if you have to raise the idle when running in order to
keep the battery charged for all the restarts, you're not going to be
saving a great deal of fuel.
Dave Plowman (News)
Chris Whelan <cawh...@prejudicentlworld.com> wrote:
> >> *I* wouldn't want to; if you'd read up-thread, you would see that's
> >> what BMW do with the Mini...
> >
> > I'd guess this is more to do with the engine start/stop system. Rather
> > than a general benefit.
> Thinking about it, if you have to raise the idle when running in order
> to keep the battery charged for all the restarts, you're not going to
> be saving a great deal of fuel.
Indeed.
--
*Can fat people go skinny-dipping?
Lester Burnham
it's happening (ie engine fully warm, revs racing at, say, 2k, when it
should be idling), disconnecting the IACV (electrically, by means of the
multi-plug) and reconnecting it cures the problem for, at a rough guess, a
couple of days. I've since done this procedure about 2 or 3 times, recently,
and it does defnitely cure the issue for a while, at least.
I've not had any further opportuinity to monitor what's happening when it
does occur (I bought a cheapo ELM 327 USB dongle for that purpose, but
haven't really had opportunity to use it, when I've encountered the
problem - either because of time, or location). I suspect I'd probably see
what I initially saw / logged - absolute throttle position at idle around
9%, after doing the Ali-shuffle with the IACV plug, probably staying at 0%
at idle.
Reading the thread about a Fiesta having an idle problem, here, makes me
wonder about ECU adaptation and the TPS. I enquired at my local dealers, and
a TPS seems very reasonably priced, so I've ordered one, and hope to fit it
in the next day or two.
Dave Plowman (News)
Lester Burnham <lester.o...@gmail.com> wrote:
> Reading the thread about a Fiesta having an idle problem, here, makes me
> wonder about ECU adaptation and the TPS. I enquired at my local
> dealers, and a TPS seems very reasonably priced, so I've ordered one,
> and hope to fit it in the next day or two.
If it is a potentiometer type TPS, they are quite easily checked. Best
with a scope to see any noise on the track while it operates, but a DVM
can show up problems. They normally wear most at the closed end.
Other way is to wire it up as a volume control between say a CD player and
amp. Any problems with the track will be easily heard as it is moved.
--
*Stable Relationships Are For Horses.
Lester Burnham
£23-24 for the OEM part from a dealers, I think even the aftermarket costs,
or costs of the OEM part from the far east were more expensive).
Changing it was reasonably straighforward - although I would say that access
to the retaining bolts are awkward for both this and the IACV (removed to
make it easier to remove the TPS) - both rearward facing, and between the
rear of the engine and the bulkhead at the back of the engine bay.
One thing I noticed from the part I took off (identical to the new one, so I
suspect it's never been changed previously), is that the default position
for the inside of the TPS (ie where it comes to rest) once removed, seemed a
fair bit different from the brand new one. Whether it was prone to sticking,
or there was any roughness in the track causing it to not fully return to
the same position as the brand new one, I'm not sure.
With everything connected up, the car started fine and idled completely as
you'd expect (although not really proving anything). I let the car fully
warm up, but didn't have chance to drive it (on account of needing to stay
at the house when I had chance to do the job). I've not had chance to drive
it, yet, but when I've managed a few days driving in it, I should have a
good feeling as to whether it's made any bearing on the problem.
Lester Burnham
My previous reply, where I'd fitted a new (OEM) TPS, seems to have done the
trick. I've not driven that much in the weeks, since, but have done a fair
few local journeys, and 3 or 4 commuting round trips (60-ish miles each way)
and had no reoccurence.
Before changing the TPS, I would have definitely had an incident of it. So
whether it was a combination of heat / warm engine and a TPS playing up at
closed throttle position, or a warm engine / engine-bay causing the TPS to
give odd readings at closed throttle, I'm not sure, but so far (fingers
crossed) a new one has done the trick.
I've not yet had chance to plug my laptop and ELM dongle in, yet, but I'll
be interested to see if there's a notable difference to when I'd logged
metrics when it was playing up.
I'm sure I'm not alone in hoping I don't have to post any further replies
about the problem returning!
Chris Whelan
[...]
> I'm sure I'm not alone in hoping I don't have to post any further
> replies about the problem returning!
usenet is most useful for.
It certainly not been the worst thread on u.r.c.m by a long way...