Hello- wild situation with a 4l80E need opinions

[Six_Shooter]

That would be doable I think. One more question, could I possibly order a new ecm from the parts store say for a 94 with matching engine/trans? This is a farm truck so not critical that I keep oem parts. I think this would do away with the clean cycle and operate the 614htz solenoid.

When you order ECMs from the parts store they don't come with the MEMCAL or PROM, so you would still need to source that and/or program your own EEPROM to be successful.

That being said, some of us have horded ECMs and might have something that might work for you.

I will have to look into this a bit more, but I don't see why the 7060 ECM won't work for you. I tune a friend's stable of cars and 4L80Es seem to end up in all of them and haven't had any issues like you are experiencing, though he tends to use earlier 4L80s with the one piece cases but both front lube and center lube, depending on what he can get his hands on. AFAIK, the internal controls haven't really changed between the update in 1994 and the two piece cases.

[1project2many]

Just want to nip a possible point of confusion for anyone new to the GM ignition...

You have your REF and EST wire colours backwards. Purple/White is the REF wire, and send the RPM reference pulses, AKA "DRP" (Distributor Reference Pulse) to the ECM and the white wire is the return from the ECM to the ICM that controls the actual timing.

You are correct, sir. Thank you for the correction.

[Plehne]

When you order ECMs from the parts store they don't come with the MEMCAL or PROM, so you would still need to source that and/or program your own EEPROM to be successful.

That being said, some of us have horded ECMs and might have something that might work for you.

I will have to look into this a bit more, but I don't see why the 7060 ECM won't work for you. I tune a friend's stable of cars and 4L80Es seem to end up in all of them and haven't had any issues like you are experiencing, though he tends to use earlier 4L80s with the one piece cases but both front lube and center lube, depending on what he can get his hands on. AFAIK, the internal controls haven't really changed between the update in 1994 and the two piece cases.

I really appreciate it. I ended up talkin with a guy about my situation and back in the woods he had a 93 4l80 so the trans shop is getting the truck back and I think he wants to try and fix it but might end up bartering the fresh late 4l80 in exchange for rebuilding the correct trans for that truck. I will keep you posted. I haven’t completely ruled out a smoked ECM. Question though if I remember correctly I was getting the same wave form on all 4 wires from the ICM. But getting a RPM with no drop outs have you ever looked at the wave forms from that?

[1project2many]

I'm unsure what you're asking. This picture shows waves similar to what the GM REF and EST will show if scoped while the engine is running. The top signal is from the pickup coil to the ignition module. The two bottom signals represent REF and EST.



If you are seeing a different signal on EST or REF then you may be seeing noise from the ignition system or another component.