another idle surg problem
 

Hello All,

I have an 83 SC. When cold start up the car warms up and finds its proper 900 rpm idle. IT runs and drives fine. Then if I stop, and then a few minutes latter, start it back up, it will not idle. It will surge from stall to 1300 rpms and will continue to do this until I run it for awhile apparently until I get it hot again. Then it is OK again.

I have searched and found many many threads but I really cant seem to match my problem. Many threads suggest adjusting the mixture screw...but I do not know where it is. Can someone point me in the right direction???

Thanks!!!!!!
mg

SURGE?

It's not recommended to adjust the mixture without a gas analyzer - should be a pretty minimal charge at you porsche mechanic. Too lean can damage the engine severely.

If it runs fine until/unless you stop it and restart, it may not be mixture.

Well the mixture screw really shouldn't be screwed with.....pardon the pun....without a gas analyzer hooked up. See the thread where the guy tried to richen it up and ended up doing the opposite and cooking the motor.

The adjustment requires a long allen wrench and is accessed under the air box. Your problem sounds like a classic "lean idle hunt".....typical of a CHT problem.

Mine is doing the same thing.

It starts great (idle is high) but after I drive for a bit, then re-start it. It hunts and then dies. It will re-start greatbut continue to hunt (I have to keep my foot on the gas and idle high in order to keep it running)

I was thinking fuel filter?

Usually a hunting is the result of a mixture that is too rich. Anyone not familiar or comfortable w/ the procedure should get someone w/ a gas analyzer to set the mixture. They should also have control pressures checked to see if it is a WUR problem or simply an incorrect mix setting.

As an alternative you can search Souk and his field test for setting mixture.