1993 Bonnie SE cranks but won't run...

[Plemmons]

I swapped the ICM out last night for a brand new one and nothing changed. Still ran fine for almost exactly a minute and then sucked a bunch of air and died. This is such a profound change, too. It's like she runs great and then all of a sudden starts sucking air through a straw, haha. It is also an immediate change; there's no gradual air coming in and slowly starting to miss, it's like a valve kicks open and lets twice the air through the throttle body as it should. I can keep the car running by feathering the accelerator pedal, but that's it. I'm thinking of troubleshooting the TPS and IAC valve on my next day off, assuming that those two are the other sensors I see in the throttle body. If any of you know any obvious signs that either of these sensors are bad, please let me know!
Thanks!

[Mechanical Mike]

Any updates?

Your scan showed 10.7 volts at the battery. A battery that's too weak to turn the engine over should still show over 12 volts. I seem to recall that some PCM/ECM's will shut down if the voltage is too low. Do you have another battery you can try?

[Plemmons]

Thanks for the reply... I did replace the battery shortly after beginning my troubleshooting. It's a brand new autocraft gold that's only 2 months old and is throwing about 12.6v. Now, before I mended the engine bay wiring for the ICM and crank position sensor, I did have to replace the PCM fuse on the passenger side because it had blown. I can't explain the huge rush of air that's killing the engine after about a minute, but after mending the wiring and replacing the ICM, I can't help but wonder about the PCM. I know a lot of people replace the PCM thinking it's the problem. I did try a new one before I found the burned wiring and the ICM tested bad, with no change. Now that the car will actually run, I can't help but want to try it again. As of now, I've replaced the crank position sensor, cam position sensor, MAF sensor and oxygen sensor. I'm running out of sensors to replace, haha.

[RJolly87]

I just had a random thought. When does the evap purge open up? I think it would start to happen about that time. If you unplug the power from it, I wonder if it would still happen? Maybe a cracked or broken evap canister or something?

[Plemmons]

I'll unplug it tomorrow after work and let you know what happens... That's a great thought and I didn't even think about the evap canister at all. I'll try that and let you guys know what happens with what i do tomorrow evening!

[Mechanical Mike]

I wonder if your small vacuum leak has become large vacuum leak. Connecting a vacuum gauge could rule out this & the evap canister.

[Plemmons]

That's what I thought might have happened, too. But wouldn't it run poorly from the very moment it fired up? The vacuum leak is around a couple of the fuel injectors; I need to get new o-rings for them, and probably just replace them altogether. The only reason I noticed this was a small burst of smoke from around a couple injectors when it was backfiring and wouldn't start at all.

[Plemmons]

Gentlemen-

Disconnecting the evap purge solenoid produced no change at all... However, I FINALLY found the problem. I believe I may have crossed a wire when I mended all this wiring in the engine bay, specifically, the wiring for the oxygen sensor. I disconnected the O2 sensor at the harness and she runs until I turn the switch off. Just drove it a few miles home for the first time in nearly 3 months and she never even stumbled. I can't imagine how an oxygen sensor could be responsible for a no-run situation, I've always seen them make a vehicle run poorly. I'm going to get back to the drawing board and see if I can get that oxygen sensor to perform properly: it is only a few months old and shouldn't be the problem.

MANY thanks to all who collaborated in this post. I can't thank you enough and just being able to look out my window and see my bonneville in the driveway instead of a random parking lot is a great feeling. I look forward to logging in here and doing what I can to help fellow bonneville owners in the future.

Thank you all once more. Today is a good day!

-Plemmons