MAF Sensor question (I know it's not exciting)
I swapped an 02 4.8 and 4l60e trans into my 91. After pulling my hair out over other issues, the truck still runs rich and is a slug from a dead stop. The diagnostic codes say the front O2 sensors are not responding. My scan tool says the O2 sensors read 450mv and fluctuate very little if at all. (truck stays in open loop) The O2 sensors have been verified to be the case ground style. All four O2 sensor wires test good (12v, ground, low feed etc). The O2's are not heating up. Fuel trims are non-existent according to the scan tool. Upon checking the MAF sensor, I found all wires test good as well, except the sensor wire (black) shows to be receiving 13+ volts. Can anyone tell me why this wire would get such high voltage and what the exact pin out is for the MAF sensor. I have come up with nothing. My thoughts are that since the MAF is not reading correctly (at idle, 7-8 grams per sec), the O2's are not operating correctly. The MAF sensor was just replaced when I thought the old one was bad. PLEASE, ANY HELP IS GREATLY APPRECIATED!!! As always, thanks.
