Help me diagnose this splutter...
GT
and it eventually went away on its own. Its come back now and I would like
to at least figure out what is causing it, if not fix it. The problem:
Its independent of gear (done it in 3rd, 4th 5th). I don't tend to rev over
about 4000 most of the time as its a nice torquey engine. Problem occurs
under load, usually at around 2000 revs. It is repeatable - the 270 degree
slip road onto the M8 at the top of Livingston is about a 50mph corner, 5th
gear. As I come out of it I speed up to er... 70 (ho humm!) and it will
splutter most times there. It also does it in 3rd coming out of the silly
little roundabouts they stick along in-town dual carriageway 40mph
stretches. Its a cough/splutter, lack of power, followed by 'beep beep'
motor control failure - go to dealer. As I feel the splutter starting, if I
back off on the accellerator and just speed up more gradually all is well.
If I drop a cog and increase the revs, all is fine.
I have ruled out dirty fuel as its been through several fill ups.
I have rules out engine temperature as it doesn't make any difference.
I have ruled out spark plugs and electrics because the revs are low, so the
demand is not so much - wouldn't this cause problems at higher revs when
there are more sparks per minute?
I have rules out air flow for the same reason - the engine isn't getting
through as much air as when the revs are higher.
This (in my mind) leaves the knocc sensor, or something else.
Any ideas / suggestions?
GT
Catman
> 156 2002, 2.0 JTS petrol. I (the car)had a splutter/cough a year or so ago
> and it eventually went away on its own. Its come back now and I would like
> to at least figure out what is causing it, if not fix it. The problem:
>
> Its independent of gear (done it in 3rd, 4th 5th). I don't tend to rev over
> about 4000 most of the time as its a nice torquey engine. Problem occurs
> under load, usually at around 2000 revs. It is repeatable - the 270 degree
> slip road onto the M8 at the top of Livingston is about a 50mph corner, 5th
> gear. As I come out of it I speed up to er... 70 (ho humm!) and it will
> splutter most times there. It also does it in 3rd coming out of the silly
> little roundabouts they stick along in-town dual carriageway 40mph
> stretches. Its a cough/splutter, lack of power, followed by 'beep beep'
> motor control failure - go to dealer. As I feel the splutter starting, if I
> back off on the accellerator and just speed up more gradually all is well.
> If I drop a cog and increase the revs, all is fine.
>
> I have ruled out dirty fuel as its been through several fill ups.
> I have rules out engine temperature as it doesn't make any difference.
> I have ruled out spark plugs and electrics because the revs are low, so the
> demand is not so much - wouldn't this cause problems at higher revs when
> there are more sparks per minute?
*maybe*
> I have rules out air flow for the same reason - the engine isn't getting
> through as much air as when the revs are higher.
>
> This (in my mind) leaves the knocc sensor, or something else.
>
> Any ideas / suggestions?
>
Is it drive by wire? If so, I'd bet on the throttle pot.
Failing that I'd be giving the AFM a stern look.
--
Catman MIB#14 SKoGA#6 TEAR#4 BOTAFOF#38 Apostle#21 COSOC#3
Tyger, Tyger Burning Bright (Remove rust to reply)
116 Giulietta 3.0l Sprint 1.7 GTV TS GT 3.2 V6
Triumph Sprint ST 1050: It's blue, see.
#www.cuore-sportivo.co.uk
GT
news:ih99na$6uk$1...@news.eternal-september.org...
Yup, I believe there is a small computer between my right foot and the
engine, instead of a cable!
I looked at the MAF (?) sensor in the air intake when I was replacing the
thermostat the other week. I had never seen a MAF before and was thoroughly
un-impressed!. I covered the top of the air intake with a cloth to avoid any
nasties getting in there, and it all looked clean as a whistle when I put
the hose back on. All has been fine for a few weeks since the thermostat
replacement, so I don't think its anything that I've introduced, but
obviously I can't say for sure!
Catman
<snip symptoms>
>>>
>>
>> Is it drive by wire? If so, I'd bet on the throttle pot.
>> Failing that I'd be giving the AFM a stern look.
>
> Yup, I believe there is a small computer between my right foot and the
> engine, instead of a cable!
Mine has a cable, alright. It's just that it carries a signal (well a
resistance really, but not sure if you can really carry a resistance) to
the ECU.
> I looked at the MAF (?) sensor in the air intake when I was replacing the
> thermostat the other week. I had never seen a MAF before and was thoroughly
> un-impressed!. I covered the top of the air intake with a cloth to avoid any
> nasties getting in there, and it all looked clean as a whistle when I put
> the hose back on. All has been fine for a few weeks since the thermostat
> replacement, so I don't think its anything that I've introduced, but
> obviously I can't say for sure!
Well the MAF on the TS was a known issue. Even if they looked OK, when
the wire got dirty, it was game over.
OTOH if it *was* the MAF, you'd maybe get issues more. I'm definiteley
leaning to the variable resistor on the throttle pedal being worn.
Zathras
<cat...@cuore-sportivo.co.uk> wrote:
>On 20/01/2011 12:57, GT wrote:
><snip symptoms>
>>>>
>>>
>>> Is it drive by wire? If so, I'd bet on the throttle pot.
>>> Failing that I'd be giving the AFM a stern look.
>>
>> Yup, I believe there is a small computer between my right foot and the
>> engine, instead of a cable!
>
>Mine has a cable, alright. It's just that it carries a signal (well a
>resistance really, but not sure if you can really carry a resistance) to
>the ECU.
>
>> I looked at the MAF (?) sensor in the air intake when I was replacing the
>> thermostat the other week. I had never seen a MAF before and was thoroughly
>> un-impressed!. I covered the top of the air intake with a cloth to avoid any
>> nasties getting in there, and it all looked clean as a whistle when I put
>> the hose back on. All has been fine for a few weeks since the thermostat
>> replacement, so I don't think its anything that I've introduced, but
>> obviously I can't say for sure!
>
>Well the MAF on the TS was a known issue. Even if they looked OK, when
>the wire got dirty, it was game over.
>
>OTOH if it *was* the MAF, you'd maybe get issues more. I'm definiteley
>leaning to the variable resistor on the throttle pedal being worn.
The MAF on my diesel Alfa failed and gave EXACTLY the same symptoms as
the OP describes. FWIW.
--
Z
Scotland
Alfa Romeo 156 2.4JTD Veloce Leather (sold)
'Oil' be seeing you..
(Email must have the word 'Alfa' in the
subject line to get through auto-filtering)
Zathras
> I had never seen a MAF before and was thoroughly
>un-impressed!.
Google for it. It's just a hot wire that's cooled by the passing mass
of air. There'll be a control box but I'd expect all you would see is
a tube and a bit of wire. It's been discussed here before.
GT
news:pupij696170kqhohc...@4ax.com...
> On Thu, 20 Jan 2011 12:57:58 -0000, "GT" <a@b.c> wrote:
>
>> I had never seen a MAF before and was thoroughly
>>un-impressed!.
>
> Google for it. It's just a hot wire that's cooled by the passing mass
> of air. There'll be a control box but I'd expect all you would see is
> a tube and a bit of wire. It's been discussed here before.
Yes - I've seen lots of talk about them here, I was just complete
unimpressed with the actual part - just as you describe - a little bit of
wire poking through the side of the air intake!
GT
news:4d383152$0$23481$c3e8da3$536f...@news.astraweb.com...
Reading around a little and there a few suggestions online that its safe to
unplug the MAF and try the car without it. That doesn't seem right to me -
sensors are there for a reason, surely? If the 'brain' can't sense how much
air is flowing, then how can it manage fuel/air mixes properly?
Dave Savage
"GT" <a@b.c> wrote >
> Reading around a little and there a few suggestions online that its safe
> to unplug the MAF and try the car without it. That doesn't seem right to
> me - sensors are there for a reason, surely? If the 'brain' can't sense
> how much air is flowing, then how can it manage fuel/air mixes properly?
>
No doubt someone will be along shortly to offer the technical explanation,
but I've seen it said many times : "disconnect the MAF and see what effect
this has". Apparently this does no harm (obviously you eventually need to
re-connect the old / replacement MAF).
Dave S... :>))
Dave Savage
>
> Well the MAF on the TS was a known issue. Even if they looked OK, when the
> wire got dirty, it was game over.
>
I can confirm this - now on my 3rd MAF (car is 12 years old, 84k miles).
Apparently the MAF's are / were manufactured by Bosch - serve us right for
putting Johnny Hun components in an Alfa !
A possibly apocryphal tale : I heard a while back that Merc had a big
problems with Bosch MAF's in their tonka toys (I don't know Merc model
numbers) - owners were bringing their Chelsea (or would it be Munich)
tractors back to the dealers in droves with MAF issues.
Dave S.... :>))
156 TS 2.0 SP3 '98 (on 3rd MAF)
Zathras
>If the 'brain' can't sense how much
>air is flowing, then how can it manage fuel/air mixes properly?
Best guess/drop back to default values/limp home mode.
I'm not sure how dissing one would help with the diagnosis though.
Unless there is a fault code, swapping out with a known good one seems
the only reliable way to tell unless you've got specialist MAF test
kit..if such a thing is available.
TonyB
"Dave Savage" <ne...@REMOVEsavamac.co.uk> wrote in message
news:4d39c56b$0$12166$fa0f...@news.zen.co.uk...
A voltage is passed through the wire which causes it to heat up. As you
try to go faster the air flow increases and the wire cools, changing its
resistance.
This allows the ECU to deliver more fuel. I guess disconnection will simply
increase the fuel flow.
TonyB
GT
I got a cable and diag software. I found 2 fault codes: P0300 - "Misfires
detected (generic) and P0303 - "Cylinder 3 ifnition failures".
"The emissions Monitoring system has detected misfires, an Air/Fuel micture
problem or other indicators of emissions exceeding the permissible level.
Check the plugs, ignition and fuel systems, and the ending mechanical
condition, and that the oild level is not too high, or oil change overdue.
Defects contribute also to O2 sensor degradeation and premature catalytic
converter efficiency loss.
The reason for this fault is that the EDU has received very high signal from
the sensor. The fault is not is not detected now, but it is stored in
memory. Clear fault codes, and observe for future appearance of the same
fault. Dashboard warning light was activated for this fault."
Sounds like the spark plug or wiring is failing on cylinder 3. I checked out
the throttle sensor and whatever I did to the pedal, the software reported a
valid position - I couldn't get the graph to flicker or jump at all.
Any thoughts to add?
So: My handbrake cable has snapped, cylinder 3 is knackered, the exhaust has
shed its outer skin and can't have long left, the air-con gave up the ghost
last year, I've spotted a few bubbles in the paint round the edges.
Otherwise, all is good in alfa land!
Zathras
>the air-con gave up the ghost last year,
My compressor was grumbling rather loudly when mine got sold at just
over 8 year old.
>I've spotted a few bubbles in the paint round the edges.
I had that too..I wasn't hugely impressed by it either. Also, bubbling
under unmarked paintwork away from edges and many seams slowly growing
cancerous lumps. My local Indy owner (who seems to specialise in old
cheap rubbish) ridiculed me over it!
Catman
<fires up babel fish>
That's a bit bloody useless really, isn't it.
'You've got a misfire, mate' is really what it boils down to.
Having said that, if it's flagging emissions exceeding the permisable
level, would it be reasonable to assume that it's because the fuel / air
is not igniting. If there was no fuel, then surely you'd get no
emissions and then no excessive emissions?
That being the case, I'd look at the plugs and such, but....
> Any thoughts to add?
>
> So: My handbrake cable has snapped, cylinder 3 is knackered, the exhaust has
> shed its outer skin and can't have long left, the air-con gave up the ghost
> last year, I've spotted a few bubbles in the paint round the edges.
> Otherwise, all is good in alfa land!
Super. It's probably hit money pit land, I'm afraid.
--
Catman MIB#14 SKoGA#6 TEAR#4 BOTAFOF#38 Apostle#21 COSOC#3
Tyger, Tyger Burning Bright (Remove rust to reply)
116 Giulietta 3.0l Sprint 1.7 147 TS GT 3.2 V6
Dave Savage
> On Wed, 10 Aug 2011 10:48:39 +0100, "GT" <a@b.c> wrote:
>
>>the air-con gave up the ghost last year,
>
> My compressor was grumbling rather loudly when mine got sold at just
> over 8 year old.
>
My air con is decidedly feeble (not cold enuf) despite re-gassing earlier
this year (by Kwik Fit so I hae me doots re the quality of the job). I'm
not a fridge engineer / factory-trained Alfa mechanic (it's rumoured these
exist), so ..... if the compressor (whatever that is) is unwell, how much
are we talking to get it fixed / replaced ?
Excuse my mechanical ignorance, I'm just the driver.
Dave S... (waiting to see if the riots extend to Surrey tonight)
GT
Yes. Another 700 miles and I'll hit the magic 100,000. I'm despirate to
reach it on the original exhaust. It would be nice if all the cylinders were
still going too!! Its been misfiring like this for a few years, gradually
getting worse, but its not a major problem from a driving point of view. My
money is on something in the spark or even the injector department. If the
injector isn't working properly, perhaps its dumping too much fuel on one
cycle and not enough in the next. Unlikely I suppose..
Catman
<snip>
>>
>> Super. It's probably hit money pit land, I'm afraid.
>
> Yes. Another 700 miles and I'll hit the magic 100,000.
Hmm. I've had considerably more out of mine, but maybe I was nicer to
them ;)
>I'm despirate to
> reach it on the original exhaust. It would be nice if all the cylinders were
> still going too!! Its been misfiring like this for a few years, gradually
> getting worse, but its not a major problem from a driving point of view. My
> money is on something in the spark or even the injector department. If the
> injector isn't working properly, perhaps its dumping too much fuel on one
> cycle and not enough in the next. Unlikely I suppose..
Very unlikely IMHO. If it's isolated to one cylinder then it really has
to be spark or something physical, though I'm not sure under what
circumstances valve or rings would not have an effect all the time IYSWIM.
R C Nesbit
> I got a cable and diag software. I found 2 fault codes: P0300 - "Misfires
> detected (generic) and P0303 - "Cylinder 3 ifnition failures".
These are the same fault codes we get on Lesley's 147 2.0TS
Code comes on, car is hard to start, rough idle and needs more revs to get
moving.
Clear the code and everything is fine, but error returns very quickly (10 -
15 miles)
This was with the generic software with the cable.
I downloaded the AlfaDiag software and it now also reveals P0141
"O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)"
Garage recons it is a burned valve on #2 cylinder
--
Rob Pearson
156 1.9jtd sportwagon (now)
164 V6 Lusso (gone)
147 2.0TS lusso (Hers)
Catman
> Gt spoke:
>> I got a cable and diag software. I found 2 fault codes: P0300 - "Misfires
>> detected (generic) and P0303 - "Cylinder 3 ifnition failures".
>
> These are the same fault codes we get on Lesley's 147 2.0TS
>
> Code comes on, car is hard to start, rough idle and needs more revs to get
> moving.
> Clear the code and everything is fine, but error returns very quickly (10 -
> 15 miles)
> This was with the generic software with the cable.
> I downloaded the AlfaDiag software and it now also reveals P0141
> "O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)"
>
Is this the lambda sensor? I thought it only had one.
> Garage recons it is a burned valve on #2 cylinder
>
Wasn't that the same garage that confused the cylinders on their
compression test, though?
--
Catman MIB#14 SKoGA#6 TEAR#4 BOTAFOF#38 Apostle#21 COSOC#3
Tyger, Tyger Burning Bright (Remove rust to reply)
116 Giulietta 3.0l Sprint 1.7 147 TS GT 3.2 V6
GT
> On 11/08/2011 08:51, R C Nesbit wrote:
>> Gt spoke:
>>> I got a cable and diag software. I found 2 fault codes: P0300 -
>>> "Misfires
>>> detected (generic) and P0303 - "Cylinder 3 ifnition failures".
>>
>> These are the same fault codes we get on Lesley's 147 2.0TS
>>
>> Code comes on, car is hard to start, rough idle and needs more revs to
>> get
>> moving.
>> Clear the code and everything is fine, but error returns very quickly
>> (10 -
>> 15 miles)
>> This was with the generic software with the cable.
>> I downloaded the AlfaDiag software and it now also reveals P0141
>> "O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)"
>>
>
> Is this the lambda sensor? I thought it only had one.
I used the FiatECUScan software (as its free) on my 2.0JTS and there are
many Lambda parameters that suggest there are at least 2 lambda sensors,
maybe 4:
Lambda 1 signal (pre-cat)
Lambda signal 2 (pre-cat)
Lambda signal 1 (after-cat)
Lambda signal 2 (after-cat)
Lambda sensor 1 integrator
Lambda sensor 2 integrator
Lambda 1 status (pre-cat)
Lambda 1 status (after-cat)
Lambda 2 status (pre-cat)
Lambda 2 status (after-cat)
Catman
Interesting
I think the JTS is a bit more complex, though.
Zathras
<ne...@REMOVEsavamac.co.uk> wrote:
>if the compressor (whatever that is) is unwell, how much
>are we talking to get it fixed / replaced ?
First Google guess ( I don't know these guys)
To this, you will need to add fitting and filling costs. At another
guess, I wouldn't be surprised if that pair added 250UKP to the
purchase price. A refill and leak test alone will be 50-100UKP (ish)
depending on supplier.
If you can see the compressor under the bonnet and it looks a simple
job to replace then the labour might well be less. The 156 tends not
to be that easy to work on and the engine bay can be a bit cluttered
however.
GT
Still not done anything about this yet, but another point to report that
might point to something specific: I've been experimenting over the last few
days and it appears to behave perfectly (faster) when the engine is cold -
only starts to splutter under heavy engine load and after the temp guage
starts to move - maybe over 60deg.