LS2 only runs right EXACTLY every third ignition cycle

[patooyee]

If I go out to my 2006 Envoy (also E40), unplug the TCM, jumper the CAN HI/LOW wires at the TCM connector so the ECM can talk to the DLC, and do a read-entire, I end up with nothing but a file with an auto trans ECM OS and no TCM. Not reading the TCM or removing the TCM after the fact or removing the TCM segments from the tune file does not change anything about the auto-trans-specific code in the ECM and how the throttle works and the info it's expecting to get from the TCM.

Thanks so much for educating me on all of this. I find it really interesting. I am still curious what the purpose of the remove controller option is though. I assume it has SOME purpose or it wouldn't be there.

Also, for my own future reference, attached is the original stock tune for a 2006 Ecotec motor I plan to use in a future buggy. Like my buddy, at one point I had the entire donor vehicle and did a read entire. I see now that it also has an auto trans. How are you cross referencing compatible applications with manual transmissions? It will also be using an old-school computerless auto transmission.

2006 Cobalt SS 24 stock tune.hpt

[blindsquirrel]

You'd have to track down a 2006 2.4L manual car, get the VIN from it, then SPS your existing ECM with that manual trans VIN (or buy one used pre-programmed to a supplied VIN). '06 2.4 is an E67 so you can't take the easy route of using a VIN from a 2.0 manual car (P12), which has tune files/VINs available all over the place.

However, there is a cheat... 2006 HHR 2.4L. VIN for one of those, same E67, built with a manual, is 3GNDA23P46S608485. Should not be any differences from the Cobalt engine hardware for a swap like you're doing.

[blindsquirrel]

Do look into why that 2.4L HHR has an 8th VIN of 'P' though, I looked a little bit and didn't find an explanation. Sometimes different platforms use different 8th VINs for the same engine RPO.

[gtstorey]

Don’t know about the reason for remove TCM setting but there are things that HPT has in it that doesn’t do much of anything or what you expect it to do. There are times that they are just getting tables defined as quickly as they can and they don’t always know exactly what they do or what use it is. Names can be misleading, units shown wrong, etc. if you deal with less common ECM’s, you will see more of this.

[patooyee]

Don?t know about the reason for remove TCM setting but there are things that HPT has in it that doesn?t do much of anything or what you expect it to do. There are times that they are just getting tables defined as quickly as they can and they don?t always know exactly what they do or what use it is. Names can be misleading, units shown wrong, etc. if you deal with less common ECM?s, you will see more of this.

I understand what you're saying, but this isn't a setting that is just mixed in randomly with others. It's a button on a screen that has no other purposes that they had to have put there with intention. It is the only actionable item on an otherwise info-only screen.

[patooyee]

You'd have to track down a 2006 2.4L manual car, get the VIN from it, then SPS your existing ECM with that manual trans VIN (or buy one used pre-programmed to a supplied VIN). '06 2.4 is an E67 so you can't take the easy route of using a VIN from a 2.0 manual car (P12), which has tune files/VINs available all over the place.

However, there is a cheat... 2006 HHR 2.4L. VIN for one of those, same E67, built with a manual, is 3GNDA23P46S608485. Should not be any differences from the Cobalt engine hardware for a swap like you're doing.

Thanks. Again, how are you able to come up with that HHR vin so easily / quickly?

TBH, the quirks involved with the GM ECM / OS combined with some other mods I had planned to do with the 2.4L made me think that maybe using Microsquirt would be better in this application. (This thread makes me think that even more.) In fact, I bought a Microsquirt system to tinker with JIC. So I'm not going to belabor this topic with the 2.4L side-topic much at this point. Still cool info though, thanks.

[edcmat-l1]

I understand what you're saying, but this isn't a setting that is just mixed in randomly with others. It's a button on a screen that has no other purposes that they had to have put there with intention. It is the only actionable item on an otherwise info-only screen.

That button is put there to detach sections of calibration for the purpose of licensing and flashing.

[blindsquirrel]

Thanks. Again, how are you able to come up with that HHR vin so easily / quickly?

Wikipedia, for Cobalt and related platforms info, then the HPT repository, then running VINs through a site like gmpartsdirect.com to check the applicable ECM service number compatibility. I'm sure that somewhere on this planet there are/were plenty of Cobalt 2.4L manual trans cars but they aren't in the repository to quickly grab a VIN from.