'96 C1500 4.3/4L60E - Misfire after Trans Swap

[AboveTheLogic]

Mechanic friend of mine says I have it right ^

Will still check the manual when it arrives.

 

[Erik the Awful]

Alright, I can accept I was wrong, but I don't understand why you'd have three pre-cat O2 sensors.

 

[AboveTheLogic]

well I guess the value here is since the code is on 2,1 the problem is affecting the odd cylinder bank, so I think that’s ignition or one of the spider injectors

I bought new ACDelco cap, rotor, plugs, and wires to put in this weekend. Was already on my to do list.

 

[AboveTheLogic]

You must be registered for see images attach

The chiltons manual I bought doesn’t have a diagram for a 1996, but here’s the diagram for a 1995 which confirms I’m focusing on the correct sensor unless it changed from 1995 to 1996. 1996 was when OBD2 was introduced.

 

[df2x4]

If you don't already have them, the factory GM service manuals can be downloaded in searchable PDF form here for free. The '96 manuals are on page nine, post number 84 by OB1214. This link should take you right to the post.

https://www.gmt400.com/threads/88-98-service-manuals.43575/post-1246113

 

[AboveTheLogic]

Thank you! I did not have those, but I do now.

 

[AboveTheLogic]

After reading through that manual, I understand P0151 is a lean condition. Not likely corrected by the cap/rotor/plugs/wires I bought.

Manual says it could be a short in the wiring - which is possible given how I just had to disconnect and reconnect everything - or a faulty injector.

I’ll be running the voltage tests it says, and go from there.

I also found all the J-39021 tester stuff on eBay for like, $145. So I ordered that. I guess I can resell it later. Yep. I guess that’s better than throwing parts at it.

 

[Schurkey]

I understand P0151 is a lean condition. Not likely corrected by the cap/rotor/plugs/wires I bought.

"Lean" O2 sensor signal can be caused by misfire.

Misfire can be caused by ignition. (Or fuel, or compression, or...)

I also found all the J-39021 tester stuff on eBay for like, $145. So I ordered that.

Do you have the wire harness adapters for the various engines?

It's a neat system, but there's FAR too many adapter harnesses needed, and it still doesn't work on some vehicles.

 

[AboveTheLogic]

I’m trying to wrap my head around how an ignition problem can cause a lean condition. If spark isn’t happening as it should, I would think unburned fuel would enter the exhaust and cause a rich condition. Maybe the PCM would then pull back fuel delivery to compensate, but that’s a bit of a cart before the horse scenario there.

The eBay junk I bought is the injector coil balancer tester, selector switch box, and the 4.3 harness. I was surprised at how relatively cheap it all was. I plan to keep this truck for a number of years so I like having the diagnostic tools available.