I have a '91 Montero that seems to be eating up ECM's. First one went and replacement lasted several years. Then one went back in November. Now one appears to have gone <3000 miles later. The parts store gave me another one for free this time and I came home and installed it. It turned on and off several times and everything was great. Now it won't start again. It turns over fine, and ran perfectly to run a couple errands, but I am currently stuck now. Things that have been replaced in the past year: Fuel pump, fuel filter, and ignition coil. Having read another thread and hoping that I wouldn't have to sheepishly crawl back to the store for another ECM and wait another two days for it to come in, I tried a new ICM, and that doesn't appear to be the problem. SO, since it fired up and ran perfect after replacing the old ECM and now won't start, I think that's the culprit, but I'm open to suggestions. The bigger question to me right now is what is causing this consistent and increasingly shorter failure? Thanks in advance

 

Seems like you have a wiring harness issue, possibly a short somewhere. I suggest inspecting it very closely.

 

Thank you for the advice. Any particular place that happens to be a weak point in the harness? I would imagine trying to peel through every wire is going to be a RPITA...

 

check your mass and tps

 

Is there a PCB or layout diagram for the ECM? There doesn't appear to be any major damage (popped leads) but one part of the ECM looks like it got some heat. It doesn't appear to have shorted across any of the other terminals (see first pic, located top left of second pic) There is an IC that appears to have been the original problem in the reman'd ECM as it appears to have been repaired previously (though haphazardly, third pic) but it too looks okay.







Thanks again!

 

Oh ****! That's done.

 

That's kinda what I was afraid of, but I had hope. Any idea what that component is in charge of? That ought to help pinpoint the location of the problem in the harness.