Please help me out HUGE problem

[baggedexploder]

Ok ive been having lots of trouble with my 93'. It would not let me pull trouble codes, and it is running like heck. TYoday I made a trip to the junkyard and picked up another ECM same year, just for a 4x4 (mines 2wd). Anyways same problem, runs horrible, and when I try to read the trouble codes with the check engine light it does not finish the test. Infact it stops just before or after the first digit of the first trouble code

 

[MrShorty]

That could be a tough one.

I would double and triple check the set-up and make sure the jumper wire isn't coming loose in the middle of the test. I might even hook up an analog voltmeter to STO and try that as an output instead of the CEL.

Then I would go through the wiring and check for loose connections: a break in EEC power or ground or in the self-test wiring.

 

[baggedexploder]

thanks shorty i have been checking wires all day, just took the upper intake off to see the wiring better, is it possible that the 02 sensor wires could be backwards? one harness is red (passenger) the driver side is black is this correct?

 

[MrShorty]

I don't know which harness goes to which O2 sensor (my '92 only has one O2 sensor), but I have heard of cases where people got them installed backwards. I would say it is possible that that is why the engine runs bad, but it wouldn't explain why you can't pull codes.

 

[baggedexploder]

definitely, well I would really like to take your advive on using an analog voltmeter, but truth is, im broke after buying the computer and all i have is a digital one from harbor freight.... It is a strange problem, it runs fine when I first start it, then after a few min it pretty much shuts down bank one. That definitely sounds like an O2 or PCM problem to me, but it is all new and the sensors give me the correct millivolt reading when hot....

 

[fixxxer]

Check for loose mounting screws or hairline cracks in your coil-pack. Heat and vibration can cause post-warmup symptoms like you are describing

 

[MrShorty]

What do you mean by "it...shuts down bank one"?