1990 100Q
So I have checked the idle switch and the idle stabilizer valve but circuits work and the valve hums. When the idle valve is disconnected the idle becomes erratic and not very smooth. With everything hooked up the car will occasionally realize that it will not low idle and it will stay at high idle. If I feather the throttle while decelerating it can idle but otherwise it will just die. The vacuum hoses have all been checked and engine vacuum is good. I recently redid the injector seals and inserts with no difference. Is there any adjustment inside the fuel distributor, like the air plate or anything I might try looking at? I have gone to the extent of even having my battery and alternator tested and they are ok. When I can get it to idle it is fairly smooth. I am at wits end!

 

The ISV gets signal from a temp sensor ... the one wire kind ... check the temp sensor and the wire

 

Thanks I will try and check that. I can no longer feather the throttle down and have it idle. It will only high idle or I must have my foot on the accelerator pedal or else it will die.

 

Update: I can't seem to get any kind of signal from the O2 sensor or the O2 sensor heater circuit, and unplugging the the Control Pressure Actuator "the little plug on the front of the fuel distributor" dropped the idle from the 1200 to the 650 and the car wasn't stalling. Oh well more troubleshooting.

 

sounds like you might have a bad o2 sensor. if that is new try to replace the gray box on the fuel dist. sounds like you might be on the right path. as far as the fuel dist adjustment.you really should'nt mess with the co mix. unless someone else has knocked out the plug. the flow plate should be about 1/8th of an inch below the lip of the bowl. happy hunting