new CIS question

[John Watson]

my 74S has a big problem idleing. the car won't idle, and hasn't for a long time. the car won't idle with the hand throttle all the way down, I have to keep it partially up all the time., I used to have a K&N filter on it and am wondering if all the oil on the filter has clogged everything up in my air metering circuit. I found that the air valve and throttle butterfly were VERY dirty and cleaned them, but no help. Does anyone have any ideas that may help.

John Watson
74 911S

[HarryD]

My guesses are:

Air leaks: Spray some WD40 or carb cleaner around all the joints in the induction system
Idle set too low: Ajdust idle
Fuel Pressures are not correct: Check hot and cold pressures and adjust/replace parts as needed.
Mixture set incorrectly: Get mixture set correctly.

It is possible that the air plate is not moving properly as well but if the car runs and you can use your accellerator pedal then the plate should be ok. On the other hand if you were rough witht he plte when you cleanded it, you may have bent something.

[fred cook]

Check the gasket on the oil filler cap. If the cap is not sealing, it will cause a major vacuum leak! An easy way to check is to take the cap off with the engine running and hold a folded up plastic trash bag firmly against the opening. If the idle goes up, then you found the problem and all you need to do is replace the sealing gasket in the oil cap. If the idle doesn't change then all you have invested is some time, cost =$0.00. Good luck!