wont idle

keith325 · 07-06-2005, 02:44 PM

1982 911
Found a vacuum leak on one of the fuel injectors so I installed new o-rings and even replaced the hard plastic sleeve that goes aroud injector. Car still runs great but will not idle. Going to check if I can find more vacuum leaks. Is there anything else that could be causing this? This started as a gradual problem with a surge RPM at idle then it started surging worse until finally it will not idle at all.

Thanks,
Keith

ianc · 07-06-2005, 02:51 PM

Keep checking thoroughly for vacuum leaks and fix all you find. When you are confident you've fixed them all, the problem may sort itself.

If not, someone may have monkeyed with the mixture to compensate for the extra air being introduced by the leaks, so you may need to fiddle with the mixture to get it back in spec. Mixture should be set on an exhaust gas analyzer.

Basic tuneup stuff such as plugs, fuel and air filters, timing, and valve adjustment should be looked at as well. Good luck,

ianc

echrisconnor · echrisconnor's Garage

Fixing vacuum leaks will lower your idle. New leaks raises the idle. You likely had your idle set to accomodate for a leak. Now that it's gone, you need to re-adjust. Just open your idle adjust screw until you have enough bypass air to idle properly.

c

Paulporsche · 07-06-2005, 03:19 PM

Both Ian and Chris are right, although they are describing 2 different things. If your mixture is right, then you may simply need to raise your idle speed. If your mixture is too rich, then you will need to reset (or have reset) your mixture. This is best done w/ a gas analyzer, although if the idle is still fluctuating, your mixture is probably too rich.

ianc · 07-06-2005, 04:15 PM

Yeah, I kind of assumed that he wasn't able to get it to idle by turning the idle screw...

ianc

keith325 · 07-07-2005, 04:56 AM

Thanks for the input fellas. I havent adjusted anything on this engine. However the fuel injectors were not replaced during the rebuild so the mechanic might have adjusted to compensate for the leak. It actually seems worse now that I repaired that one severely leaking injector seal. I might have to take this thing somewhere for the air/fuel mixture calabration.

Paulporsche · 07-07-2005, 05:06 AM

Keith,
That's probably safest. If you search, you will find many of us adjust our own mixtures using a variety of methods. If you are unsure of this, then take the car to someone w/ an analyzer and see how they do it. It won't be too costly and you will then have a baseline. JW recommends a 3.5% CO setting for these cars.