Greetings all, I had a thread about a month ago about my MAF putting out low numbers when trying to tune the car after hot cam install. I got a new AC Delco MAF and got the exact same numbers...this makes 3 MAF's that give low numbers. I called a guy with a 94 like mine and put my MAF on his car and got the correct numbers, so I know it's not the sensor. I then checked the ohm resistance on all three wires (ground, fuse, ECM) and got zero resistance. Another electrical issue is the computer won't turn the fans on and it has done this since I got the car 5 years ago..long before the rebuild. I've installed a fan over-ride switch, but the only way the computer will turn the fans on is if the SES light is on. Do you guys think I might have a corrupted computer? All of my body grounds are good, all the voltages to the MAF are correct, and everything else is working fine. I'm pulling my hair out... any advice or thoughts would be greatly appreciated!

 

So you had no resistance between the wires on your maf to the PCM? One is the 5 volt refernce (5v at all times w/key on), one is an ecm simulated ground, and one is the signal voltage sent to the pcm. What did your signal voltage read at the MAF? should be something like 1 volt at idle and 5 volts at WOT.

You also need to make sure of the voltages at the ECM. You should see 5 volts with the key on for the reference voltage pin, see a voltage DROP of 0.1 or less for the ground, and see the same voltage at the signal pin as you do the signal output from the sensor.

If something is different then you have a wiring issue. And to accurately test the sensor ground at the ECM put the negative lead on the ecm pin and the positive to the battery or battery voltage. You should read battery voltage any variance of .2 Volt or more= bad ecm.

 

The voltages going to the MAF from the fuse block is 11.89 (yellow wire), the signal voltage from the ecm is 4.89 (pink wire). When I say I got zero resistance in the wires, I was making sure that I didn't pinch or short out a wire during the removal/installation of the engine. When you say put the negative lead on the ecm pin, do you mean disconnecting the harness from the ecm and testing the pin on the ecm? Or at the sensor?

 

what year camaro?

 

alll right after tripple checking i see its like a 94, lol. check ground wire to see how it ohms out.

 

Yes, it's a 94. The MAF ground ohm was zero from the connector to the negative on the battery...