jc22

I just bought my first 951 and it seems to have a problem with the idle. When the engine is cold (if you see where I live, cold is a relative term)it stumbles and acts like it is going to stall. When I touch the throttle, the revs actually drop a little like it is REALLY going to stall. Feels like a fuel mixture thing to me.

The PO said he thought it was a bad injector that gums up when it isn't driven much. However, once you get the revs up it doesn't stumble at all. When the engine gets up to temp. it idles fine.

I did a search here and found that it could be a bad temp. sensor on the engine telling the computer the engine is warm therefore not richening up the mixture when cold. Is that a possible cause?? What about this stabilization valve thing I've heard about?? Any ideas, thoughts, or experiences would be appreciated. Thanks in advance.

Songz

Any Mods to the Car? Sounds like improper fuel Map to me.

Anyway, this may sound stupid but its worth a try: Next time the idling problem comes out again, try opening the hood, see if it gets better...

Cheers

jc22

No mods other than some kind of cat-back that I know about. I was told from the seller who appears to be trustworthy (PCA member and racer) that the only things done recently were-- new clutch, new timing belt/water pump, all new seals on engine, and some kind of boost regulator.

Somebody has to have an idea about this right??

BTW, I have had the hood open during startup (battery was dead) and it happened all the same. Are the injectors always that loud?!?!

Songz

Just some my opinion (I am no expert);

How many miles on the Injectors? The loud sound you're hearing could be shot lifters.

there are a couple of things you can try:
1. Buy some fuel addictives that can help clean up injectors.. see if the idling gets better.
2. Checking all hoses and Idling stabilizer. Something could be wrong there.

....

Good Luck!

turbo944

Very much so....do check those hoses!! Found the one that runs from my manual boost controller to the intercooler to throttle body pipe had broken when my idling suddenly was way down early this week. That hose losing that connection made it idle really badly just after startup (been "chilly" here for far too long...) and once warmed up it also seemed to idle okay. Also ran great above idle without any problems. Still idles a little fast, looks like someone tried to put sticky stuff in my idle adjust screw...another thing to play with this weekend if the temp gets up decently.

Cheers!

MHT

check the throttle bore, clean it with a rag and some carb. cleaner, also check that the throttle switch clicks at idle. Make sure that base idle speed and mixture are correct, check idle speed by bridging terminals B and C in the diagnostic connector in the left rear corner of eng. compartment. Idle speed will be close enough when there is no difference in speed between bridged and not. To set mixture you really need an emissions analyzer, but you may be able to get it close by ear. Disconnect the O2 sensor and turn the screw in the air flow sensor until you get smoothest idle. Good luck Mark T.