Porschenut_Lee

From my searches, this AFM voltage is really low. Look almost dead center of screen shots where it says "MAF" Any thoughts? Is my flapper not opening all the way?

Also getting a 50% knock rate still, and it looks my timing is retarded as a result. Would the fault code for the #2 knock sensor give an indication that maybe just the sensor is bad?

Porschenut_Lee

Anyone have any thoughts on the effects or issues that this may cause or those which may be causing it? After the ignition overhaul my power is up substantially. I just happened to notice that this voltage seemed low.

Goughary

Are you thinking its low at idle and ok at 3200? Or both low.

Does the car have a single belt pulley conversion?

Porschenut_Lee

My understanding is that the voltage should start over 1.0v at idle and increase up to as much as 5v with RPM. Should be a linear increase as the flapper opens.

If anyone else has UDT / PDT I would be interested to see what you guys are getting for values.

-nick

993 has a maf, not sure if late 928 models do also. Is it possible that the UDT is in a 993/maf mode? AFM voltage at idle will be around 1.3V. Assuming engine is warm and ambient temp is ~60F. Holding 3k rpm with no load, you'll see about 2V out of the afm. You're correct, it is a linear 0-5V as the flap opens. It will peg at 5V around 5k rpm at WOT.

Idle spark advance is wonky too. Stock chip will give 0 degrees, aftermarket chips will be around 4 degrees advance. The -4 is indicating retard. Injector pulse widths look normal, the "load" value.

I would say that the meter is in a 993 mode.

Porschenut_Lee

Thanks Nick, I'll have to check my settings and run it again. I just took for granted that even though it says MAF.....it is giving me AFM values for the 964. I have the old version software. Wonder if it is worth an upgrade for the new user interface.