Hello,
My 1997 MPI mini currently increases the engine idle revs as the engine warms up. I first noticed the issue when driving the car, ever so often, the revs would increase when you depress the clutch to change gear. After experiencing this for a few times, I took the air idle control value (AICV) apart and cleaned it up. This seemed to make no difference and the car ended up going back into the garage for a few months due to other commitments.
Keen to get the car back on the road, I bought a new AICV with the lower elbow bracket and installed it along with a new lambda sensor, as this was advised at my last MOT. This didn't seem to make any difference and the car would then start and idle at 1200rpm and start increasing as the engine got warmer and continue up to 4/5000 RPM, at which point I'd switch the engine off. I have now replaced the throttle position sensor, water temp sensor, inlet/exhaust manifold gasket and checked that the injectors are not leaking and that there are no air leaks on the system and none of these changes seem to have resolved the issue.
The only time I can get the car to idle correctly is, once the car is warm and revs are increasing, to stick my thumb over the air pipe that takes air from the butterfly housing on the manifold to the AICV. This then brings the car back down to 900rpm and the car will sit there until you remove your thumb. To me this means that the AICV is stuck open and the ECU is not telling it to shut once the car has warmed up.
I'm now struggling as I do not know how the ECU tells the AICV to shut. I would appreciate any insight someone can give me on how to resolve this issue.
Thanks
