Quote Originally Posted by dave w View Post
My schematics are for a 2002 Express Van 5.7 Liter. I've used the schematics to build new Stand-Alone harness for both the Vortec 5.7 and Vortec 7.4 (1996 - 1999).

The sensor part # information below is from RockAuto: Same sensor part numbers, same wiring. There might be more than one source in the '0411 for 12 volts and sensor reference. There is only one place the sensor signal can be wired to. Check the sensor connector wiring, by unplugging the connector from the sensor ... Key On / Engine Off measure the pin voltages on the unplugged connectors.

The MAF will send a signal Key On / Engine Off if you have air flowing through it, like a blast of compressed air. Caution, do not BLAST compressed air next to the MAF, about 6" away from the MAF is safe.

dave w

2002 Express Van 5.7
CKP – SMP PC123
CMP - BECK/ARNLEY 1800750


1998 C2500 7.4
CKP – SMP PC123
CMP - BECK/ARNLEY 1800750
I can get it to fire up with the MAF unplugged. So I dont think CMP/CPK sensors are bad or mispinned. I'll check voltage later tonight when it cools off. I'll also visually inspect the maf to see if its dirty. I find it hard to believe the MAF is dead as it worked 8 hours earlier