dkcaims

Anyone know the proper volts reading from AFM to DME at idle?

Last ditch effort before it goes back to my tech for diagnosis.
Mine reads 1.41 volts at idle, but if it should be .60 to .80 for example, that might be the cause for my rich mixture.

Thanks

Makmov

where are you measuring it?

Should be 5ish volts @ pin 3

250-260 m V across the potentinometer 4.60 V wide open.

dkcaims

Agreed !
Forgot where I found this and I'm not even sure these values are even for a 964...

1. FULL-SWEEP - with the key to ON but engine not running, have a an assistant slowly open and close the flapper door on the AFM fully. The voltage should be 0.25v when it's fully closed, 4.60v when fully open. Should rise and fall smoothly with no sudden jumps or dropouts.

2. IDLE - at 900rpm you should be seeing 0.79-0.85v.

2. 3rd gear - at 3000rpm steady-state should show about 2.3-2.5v. Gentle 1/4-throttle acceleration from here should show 3.0-3.5v.

My car measured directly at the AFM and DME plug. Has the full range measured with the ignition on and not running = .25v to 4.6v.
The concern though is whether the value at idle, approx 850rpm, is where it should be.
Correct me is I'm wrong, but the DME will pulse the injectors based upon a number of things. One of which is the volts reading from the AFM. The more volts, the more fuel.

Makmov

That's the way I read that, so if you have a high voltage reading at idle I would think the DME thinks the AFM is open further than it really is.

dkcaims

Taking the car in to my tech this afternoon... Hopefully he can figure this out.

Makmov

oh dear lol

dkcaims

My tech can't get to it until Aug 6th.
Suggested I try Steve Rowe of Rowe Performance.
Seems to have a stellar reputation !

Makmov

Did you ever check the fuel load contact?

dkcaims

You mean the microswitch at the throttle body? Yes, within spec.

Makmov

resonance plate?

Tank valve?

does it have any codes?

dkcaims

I'll let Steve figure it out... I'll let you know.