I am almost done wiring up the new PMAS MAF in my 92 GT. The thing that strikes me as odd is that on the wire for the MAF return I am seeing 5v KOEO. Is this normal? We have already tested continuity on pin 9 of the EEC to verify it is the right wire. Any help would be greatly appreciated.
You always measure between pins on the MAF, not pin to ground. The MAF circuit uses a differential ampliflier circuit which uses the difference in voltage between the two outputs to determine what the signal is.
Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer. Be sure to measure the sensor output by measuring across the pins and not between the pins and ground.
The figures below are approximate outputs with a stock system. Your results with aftermaket parts may be different.
At idle = approximately .6 volt
20 MPH = approximately 1.10 volt
40 MPH = approximately 1.70 volt
60 MPH = approximately 2.10 volt
You guys are lifesavers. The voltage was perfect when measured across pins. Seeing +5v on the maf return just made no logical sense to us and I do have an electrical problem somewhere in the wiring that is causing battery drain when the car is off. I just wanted to be sure I didn't accidentally stumble across the problem wire. Thanks for the help guys.