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[superspy]

or is it just a case of when its fubar its fubar?

my car keeps randomly cutting out when i back off the throttle and dip the clutch (ie, coming up to a junction) but its completely intermittent, one day it will do it constantly, then the next day nothing at all.

also, could my excessively rich nitrous mixture be caking it up with fuel and thats whats causing it to fail?

obviously at this point im only assuming that it is indeed the ICV causing the problem.

cheers

kyle

[Noswizard]

Unfortunately that could be a number of potential problems and unfortunately they're all outside my range of expertise.

I hope one of the other guys will be able to assist you on that one Kyle.
_________________
Trev (The WIZARD of NOS)

[superspy]

no probs, thanks for answering anyway, i'm only going with ICV at this point as a gut instinct because i've seen many cars do the same sort of thing and that was the problem (mainly fords interestingly) but also because it did it the other day, i took the connections off, blew them, plugged them back in again and it worked, lol

[MikeT]

Kyle, I'm chasing a similar fault on my Granny and it isn't just the ICV that will cause return-to-idle stalling. The commonest alternative is an air leak - sometimes caused by not renewing the ICV gasket after a clean!

Yes, it will benefit from a clean, just as the TB does while you're at it.

There are three tests I can think of. 1.Resistance between two contacts of ICV. 2.Operation of the solenoid and 3.voltage from the harness.

Oh, and don't use WD40, use carb cleaner and ensure it's thoroughly dry before refitting.

[superspy]

thanks for that mike, i'll do some investigating tomorrow (on my day off, lol), hopefully it wil start this morning.

[DebsTF]

Aside from the usual culprits (coil packs, HT leads), it could be something as simple as the IACV Stepper Motor needing to be reset.

To do this:

1) Start the engine and warm up to a normal working temperature.
2) Turn off the ignition.
3) Turn on ignition to stage II but don't start the engine.
4) Press the accelerator all the way down and fully release five times.
5) Wait for at least 15 seconds and then turn off the ignition.

It could, however, be a fault in either the GREEN manifold inlet temperature sensor, the camshaft position sensor, or the crankshaft position sensor.

Try the stepper motor reset procedure. If this doesn't work you will need to get hold of an OBD II compliant fault code reader to see whether there are any fault codes stored in the ECU. Better still would be to plug the car into a T4 Testbook since this will show up any faults in the various sensors.

[superspy]

ok, il give the stepper motor reset a try, failing that, does anybody within a short distance of doncaster have a T4 testbook? lol

also, could any of this be caused by the garage that did my head gasket? or is it more of a wear and tear thing?

[daveg360]

ICV problems are rife - Alfa, Renault, Vauxhalls etc etc. I think they're mostly Bosch units. Can you pull away without using the accelerator? Has the car got AC? does it respond to the demand of the AC quickly or to the revs dip?
As Debs says - get it on a EOBD reader. They're pretty cheap on ebay and there's free software around. You need an ELM323 or greater (ELM327 includes CAN).

[superspy]

yeah i can pull away without the accelerator, this is what im saying, the problem is completely intermittent.

even stranger, i did the routine for resetting the stepper motor, and when i fired the car up again, it nearly cut out almost instantly, and again, every time i revved it and backed off, the revs would fall very low again (the only thing i noticed different was that the revs wouldnt bounce above 1k rpm, they would just come back up and settle straight away). then i cut the engine, restarted, and everything was fine. i thought this might be a fluke, so i tried again, reset the stepper motor again, and sure enough, when i fired it up, it was eratic again, cut the engine, restarted and all was fine. weird.

[DebsTF]

I guess you need o find an ex MGR dealer then Kyle and get hooked up to a T4 Testbook.

[superspy]

great stuff, well it hasnt got to a point where its every day or anything, so i can live with it and try the cheaper options for now. funnily enough its been absolutely fine now, no problems what so ever.

[superspy]

for anyone that is interested, i have done 3 things to my car today.

1. oil change
2. refitted my induction kit properly after the garage that did the head managed to **** it up, covering half of my air intake with my RADIATOR!
3. refitted my coilpack/HT lead plastic cover.

funnily enough it seems to have a nicer idle, and the revs dont bounce when it settles anymore.

im thinking perhaps the warm air thru the induction system, combined with the ht leads potentially earthing out on the bonnet could have caused the problems, but we'll see if they re-occur over the next few days.