Winter hilarity caused by erratic (high) idle speed 1990 RRC auto
Richard Savage
intermittently rise to around the 1800 mark . This can last for the
whole of my journey to and from work ~ 17 miles and is fine on the
dual carriageway but unnecessarily exciting in crawling traffic or ice
covered lanes. I'm presume it's not going to do the auto box a lot
of good either
Any thoughts? Air leaks have been suggested but I know not how or
where to look for them. An engine re-start _seems_ to reset the idle
speed but not always for very long.
TIA
Richard
William Black
Air going from very dry to very wet as your engine thaws out the snow on
the bonnet?
--
William Black
"Any number under six"
The answer given by Englishman Richard Peeke when asked by the Duke of
Medina Sidonia how many Spanish sword and buckler men he could beat
single handed with a quarterstaff.
Richard Savage
>
> Air going from very dry to very wet as your engine thaws out the snow on
> the bonnet?
>
> --
> William Black
>
Thanks WIlliam,
No, it seems unrelated to the moisture content.
Richard
Tom Woods
I assume the RR has an IAC to control the idle?
The one on my car keeps doing similar things leaving me with an idle
of 2000-3000. If i then manage to stop and open the bonnet and hit it
it goes back to normal, or it does it on its own - sometimes quicker
if I turn the ignition on and off a few times.
Second hand ones are cheap on ebay if you want to try a swap.
Lee_D
news:180aa78e-f9ce-4c9e...@h9g2000yqa.googlegroups.com...
I had the problem on an '83 V8 RRC Manual. Im my case the Advance retard
unit had a perforation in the er..erm.. diaphram in the unit allowing air to
be sucked through and screwing up the timing. The engine pulsed but revs
seemed to sit lowest around 1100 rpm and upwards.. Equally as fun at
junctions and the lights as everyon assumed I was up for a race.
May be completely unrelated but similar so though it worth throwing in the
the idea pot.
Lee D
Badger
"Lee_D" <newsgrou...@NOSPAMlrproject.com> wrote in message
news:4b33ba6a$0$2488$db0f...@news.zen.co.uk...
And if you get to the bottom of it, please tell us!
I have a regular customer who has had over 15 hours of free labour on his
disco 3.9 now, because I won't bill him if I can't effect a cure. His does
something similar, occasionally racing up the revs but it will come back to
normal idle as soon as you come to a halt and then select N or P on the
autobox, then it is fine until it next goes over 20mph then the cycle starts
again. If you stop then restart within say 2 minutes it does what it
should - fires straight up and runs to 1400rpm then settles almost
immediately back to idle, yet if you let it sit for more than 5 minutes it
will not fire without giving it a little throttle and holding the revs up
manually for a few seconds until it clears its throat!
So far, it has had:-
2 x idle speed stepper motors, both new.
a 3rd stepper motor for diagnostic purposes, taken from a good running
vehicle.
Ecu replaced, no different so original refitted.
Base idle settings checked & adjusted.
AFM replaced with known good unit.
Throttle position tx replaced.
Temp sensors (water and fuel) replaced.
Wiring inputs (and voltages) from autobox neutral switch and road speed
sensor all checked ok.
Harness con-checks carried out ok.
Fuel pressure checked ok.
New plugs, leads, arm, cap and vaccum advance capsule.
New ignition amp and coil.
This is the first time I've ever been beaten by a rover V8.......... and
it's pissing me off severely!
Badger.
Dave Liquorice
> This is the first time I've ever been beaten by a rover V8.......... and
> it's pissing me off severely!
Software bug in the ECU?
--
Cheers
Dave.
Oily
"Badger" wrote.............
>
> This is the first time I've ever been beaten by a rover V8.........
Admit it, you've been driving a 2 1/4 diseisel. :-)
JacobH
What are them there sensor things in the exhaust? Heard tell they make
them do funny things when they're not right.
--
JacobH
Bah Bumhug
Wisdom and experience come with age, they say, but I do wish I could
remember the darn question
Badger
"JacobH" <Geoff_Ha...@IEE.ORGasm> wrote in message
news:NpmdnYG_Nrordq7W...@brightview.co.uk...
Lambda probes - they tend to either work ok or wander off one way or the
other (rich or lean), but they don't give erratic indications as a rule, and
they have no control over rpm.
Badger.
DerekW
"Richard Savage" <r...@nildram.co.uk> wrote in message
news:0db844f3-b735-4fc4...@c3g2000yqd.googlegroups.com...
In my case on an 89 Vogue SE it was a faulty plug on the sensor that was
about 7 years ago so I can't honestly remember which of the temp senders was
giving an erratic reading and causing the ECU to read the engine as cold so
go into the fast idle mode
your choice but one of the pair on the top of the engine. They are cheap as
chips
from your local Prince of the Sudden Lack of Light dealer
Derek
G8KBV
brian...@btinternet.com says...
Hi.
Have you looked at the Pico Scope tutorial site?
http://www.picoauto.com/automotive-library.html
Lots of interesting info, in the "Real-Life Diagnostics" section.
And as to Lambda sensors... Scroll down to...
"Best of the Rest".
You don't need a specific make or model of automotive osciloscope to
make measurements, just one that will do the job (without itself
suffering) and the right info so as to diagnose the problems.
As I said above, lots of good info on that site. Hope something helps.
Regards.
Dave B.
Richard Savage
B********d thing has stopped doing it (for the present) which is just
as good now that the roads resemble ice rinks again.
As far as I can tell the IAC (Ignition Advance Control?) is fine.
When I aquired this RR the advance was faulty - pierced diaphragm -
but this had no noticeable effect on the running of the engine! I
will have another look at it though.
Possibly a bug in the ECU which may explain why power cycling
sometimes cures the fault.
No lamba probes in my CAT-free heap.
Temp probes on the top are a good route to try (nice and cheap)
I must confess that it has always run cool.
Cheers
Richard