stein944

Idle speed drops to < 400 and engine stalls whem warm. Starts and runs OK until warm. The problem turned up suddenly one day. The car is in generally good condition (< 100 000 km), no other issues.
I have replaced the DME and visual inspection does not reveal major issues with the throttle position sensor.
Is there a simple way of testing the idle control valve in situ?
Thankful for advice!
Stein

floatingkiwi

AFM connected/no pin corrosion? It should run like a dog if the ecu has no AFM signal but will run. Or somehow running very rich will also do this.

Noahs944

I dunno if this would cause your problems but there is a module for spark that's relatively cheap to replace and might cause this.

stein944

Thank you!
I applied el. contact spray on connectors and it seemed to attenuate the problem - engine does not stop. But the idle speed is still low at 600 RPM.
I have not found instructions for modifying 944 S2 idle speed anywhere.
Stein

floatingkiwi

Yeah you can't it's done by the ecu. The idle control valve may be at fault (or an air leak). My race car would idle low and I found it was insanely rich.

stein944

It seems the Idle control valve is OK - it least it produces clicks when served 12V from the battery.
The explanation that the engine is running rich seems reasonable to me.
How do I fix that? What is the culprit?

floatingkiwi

well mine was a fiddled with afm for racing (so I ended up opening the idle mixture/CO2 screw on the AFM). Really need to dyno to know for sure.