Engine stalling whilst driving - help!

[notax]

Engine seems to be running perfectly (standard 400) and generally idles at a steady 1000rpm. However, in last couple of days keeps stalling when I'm slowing from high speed as soon as I dip the clutch. I've cleaned the stepper motor and she's just had a 12k service. Any ideas?

[Griffter]

On mine it was the stepper not reacting quickly enough. Cured it by adjusting the throttle bypass air bleed screw, with air pipe to the stepper clamped off, so the engine idled at about 800-850rpm when warm. That way even if you dip the clutch with the stepper closed, enough air gets past the throttle to keep the engine running.

[notax]

Thanks. I'll give it a try.

[GreenV8S]

See if the inside of the throttle body is clean, maybe somebody has 'corrected' the base idle to compensate for a gunked up throttle instead of cleaning it properly.

[paul garabette]

notax said:

I'll give it a try.

How did you get on, notax. I am watching this thread with interest. I also get the occasional stalling when stopping, and the explanation seems to fit.

Is the "throttle bypass screw thingy" the allen key operated screw accessed from above just next to and rearward of where the air intake/airflow meter hose joins the plenum? Mine is stuck solid despite overnight WD40 soaking Any ideas? I'm resisting giving it some major allen key snapping force in case I do some damage.

Paul.

[notax]

Hi Paul. No news yet - car is working perfectly today, but will be heading to the garage later this week. Also needs new shocks, starter motor and brakes - expensive few weeks ahead... I'll post up the results of the garage's investigations and success (or lack of) in dealing with it!

[jsr]

Mine also dies every now and then when coming to a stop. I currently have rubbish full economy (13mpg) and it really struggled with recent emissions test. I have suspected lambda sensors. I've now got a fault code reader and sure enough, have a lambda sensor out of range fault.

Just need a bit of dry weather to fit the new sensors. Hoping it will cure the stalling problem too

[over_the_hill]

I had a similar problem and like jsr had poor economy (although not as bad as 13mpg)
and failed the emission test.
This was the Lambda sensors. Under normal running the engine can keep itself going
even though the Lambda is giving a duff reading and causing the mix to be too rich
(hence poor economy), but when you come to a halt and are just idling the rich
mix is just too much for it.

[notax]

Pleased to say that poor economy is one of the few things I'm not suffering from! Car runs really well most of the time - in fact was most powerful standard 400 Surrey Rolling Road has ever tested!