1991 exp maf-fuel issue won't stabilize

[tireman406]

I work at an auto shop. Yesterday morning on my way to work my cel came on and went off and came on... scanned and it pointed to maf. Removed it cleaned it replaced it. Started it up drove fine no cel. Later in the day i pulled it up on our lift for a little under car tlc with degreaser and our preasure washer. After finishing my cleaning job lowered vehicle back down and fired it up. It will not rev, push in on the gas pedal and the motor starts to rev and drop rev and drop. After a minute or so it will stabilize on its own but the next time you hit the gas it does it again. Tried recleaning the maf and it didnt change. With the motor running unhooking the maf doesnt change the idle at all. Called our parts house had a new maf sent over. Plugged it in no change as far as running. Replaced old maf.

Does anyone know if you can check the wiring between the maf and the pcm to insure the signal from the maf is being sent to the pcm? I know that in the past when i have unplugged my maf the vehicle will just die. It is running like it did when i got water up through my airbox onto my maf and had to wait until it dried out for the vehicle to return to normal running conditions. I also cleaned out the iac and tps from the insidde of the intake and am wondering if maybe a piece residue could be causing this issue.


Ok long thread short do you have any ideas as to what i could try next? I am going to test the maf in the morning to ensure it has 12v, ground, pcm ground, and voltage fluctuation while running. I also went back under the vehicle and made sure all wires were connected.

Thank you in advance if you have any ideas.

 

[tireman406]

Quick update. Tested maf with a multimeter today and all the wires checked out. I did yet again unplug the maf while it was running and still no change in the way the vehicle ran which i think it should change. Also while the vehicle was running i unplugged the air sensor connected to the upper right hand side of the plenum and the vehicle tried to die. Plugged it back in as fast as i could and it kept running crappy as i may be. I next unplugged the tps and no change in running. During each of these steps i try the throttle manually to see if the engine will actually rev and hold as it is supposed to. But no luck. I am super frusterated at this point and would greatly appreciate some help!

 

[tireman406]

Ok well no one ever responded but I did finally figure out this wet poor run condition. Turns out if your cam shaft sensor is missing it's rubber grommet where the wire plugs in the .it will create a hell of a poor run condition. Always just thought my ex was allergic to water (which is terrible for an off road vehicle) but if anyone else has this off issue check the cam sensor plug for water short issues.

 

[kirkallen143]

Don't you mean your crankshaft position sensor? I figured since you were cleaning/pressure washing from under the ex., and yours is a '91 which has no cam sensor, so called synchronizer. Thanks for the most greatful information and diagnosis.

Kirk

 

[Centaurious]

I wondered why you were so focused on the MAF when you created the problem during a cleaning of the engine. Used to be it was water in the distributor cap after washing the engine bay.
You can't find the answer if you can't state what the problem is.