Somebody help,

I have a 1989 chevy camaro iroc-z auto with an L98 350. Now when start it up it pulses up to about 1200-1500 rpm three four times and then shuts down. I repeat that process about 4-5 times and then it will turn on sometimes it takes more tries. Then while I'm driving the Service Engine Soon light comes on. So I checked the trouble codes and it shot me a 12 for diagnostic and then a 34 which read this in my Haynes manual as:

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Trouble Code / Circuit or System / Probable Cause
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34 / MAF / Poor electrical connection, open or short in circuit; defective MAF sensor; defective ECM
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Do you guys think it is indeed actually the MAF sensor? Or could it be the ECM (Computer)? I have money to fix one of these things at a time, what should I replace first? How can I pin down or more closely determine which it is? Is there another way for me to trouble shoot this? I'm leaning towards checking all the connections cleaning all the harnesses and clamps and if it still continues replacing the MAF first. Help me out here guys any expertise here would be greatly welcomed.

Thanks
ronin1274

 

This may or may not help you, but I just fought a problem simular to this. The problem was the ECM/ESC ground wire on the back of the left (drivers side) cylinder head. The crimped on terminal was corroded and not giving the computer a good enough ground for it to operate. I removed the terminal, crimped/soldered a new one on, problem solved. Easy to check and one more possible problem to eliminate. Also check your MAF relay and conncetions.

Also pull your ESC wire and see if your engine runs better. This drops all sensors and the computer off line and you are running on the distributor, coil, and not much else. I found my problem while attempting to use a timing light and saw that the ignition was cutting out on me when the computer was running the engine, but in limp home mode it I wasn't losing spark.

Good luck.

 

How do I pull the ESC/ECM wire to try running it computer/sensor free?? Where exactly is that ground wire on the back of the driver cylinder head by the way??

 

The ESC wire is on the right side of the car in the harness. A tan wire with a weather pack connector. Disconnect it then try starting the car.

As I said, the ground is on the back of the left (drivers side) cylinder head under the wire harness. Start looking/feeling around and you will easily find it.