peanut

the car drives perfectly at all times cold or hot.

It is only at idle that there is a rich idle mixture issue. I have removed and stripped the AFM adjusted the wiper track and added a wire bypass to the wiper arm as per Clarkes garage guide . The AFM tests ok but I have not yet tested the signal to the ECU which is next on the list . I have also tested the TPS which is also fine and replaced the engine temp sensor in fact everything that the OP has done

rusnak

^ You mean you checked the idle position switch with a mulitmeter?

rusnak

I should add "Don't whack the **** out of the injectors like a caveman. They are delicate like a flower."

How is that different from driving the car, but with a lot less voltage?

peanut

no not just a resistance test but simulated voltage operation and shutting off the bypass pipe with a clamp and also running the car at idle with the electrical connector disconnected . Correct ICV operation is to cold starting on later cars

The engine temperature sensor registers the cold water temperature in the engine so the ECU supplies a voltage to the ICV coil which opens up and allows air to bypass around the AFM . The increased air causes the ECU to increase pulsing of the injectors for a few seconds to balance the fuel mixture thereby giving a rich cold start mixture .

rusnak

There is an CHT sensor, an oil temperature sensor, which does nothing per se, and an air temperature sensor in the AFM, which I assume you checked when you tested the wiper track output?

Amber Gramps

I think he called the CHT something else.

I just started pulling out my spark plugs after 10 years. and they look fantastic. Kind of a deep red color...

I still think peanut's issue is a fuel injector that sticks and continues to flow more fuel than it should.

LOL....didn't read your post.... My buddy Gonzo uses an ultrasonic vibration tank like jewels use. My stock injectors were within 1% of each other I think.

rusnak

10 years? Shame on you haha! Porsche says I have to change the plugs on the Cayman at 40K miles. I *just* figured out how to remove the wheels without the anti-theft key, so it's new tires then plugs. I'm thinking the coil packs should be changed while I'm in there but I'll have a look at them first.

I agree with the stuck injector as a possibility. I just changed mine when I changed the fuel lines.

Amber Gramps

They may have 30K miles on them....and I was telling one of my local Asian gang members that some of the plugs are tricky and he said try changing 12 of them (964)...LOL...my car has had a grand total of 12 plugs in it's entire life

peanut

I think you were partially right Gramps. It turned out to be the FPR diaphram letting fuel into the vacuum system and ultimately the inlet of course.
A new FPR seems to have cured the problem although it still seems to be running a little rich at idle causing a slowly fluctuating idle , hence the guess that a leaky injector could be at fault.
At least its holding fuel pressure in the rail now and starting on the button again.

rusnak

Turn the engine off. Does fuel pressure drop? Oh, and don't forget. Your fuel injectors are like a delicate flake of snow.

peanut

refer to post #9

car starting and running fine now . Problem was an intermittent leaking FPR leaking into the vacuum system (causing a rich idle cold start mixture) NOT leaking fuel pressure via the fuel pressure return line.

How is your diagnostic /repair method of whacking things working out ?

rusnak

^ You did not post your operating fuel pressure, nor systemic fuel pressure. That is how you test the fpr and for a leaky injector. Re-read your post # 24.

peanut

I do not need to..... I have already stated that the fuel pressure and system are functioning fine and the issue was a FPR which has been replaced.
Its not clear what you mean by 'systemic' fuel pressure ? perhaps you are referring to residual fuel pressure which is the measurement of how much the fuel pressure drops over time after the ignition is switched off as specified in the Porsche manual

I cannot for the life of me work out why you are still persuing this .....

rusnak

^ OK whatever. Your posts are all over the place. You stated in Post #24 that:

"although it still seems to be running a little rich at idle causing a slowly fluctuating idle , hence the guess that a leaky injector could be at fault.
At least its holding fuel pressure in the rail now and starting on the button again."

Now you're being so dramatic and stating that all is fine.

Forget it. I guess you like drama.