I have a '92 Cutlass that I've just completed swapping in an L67 and 4T65e-HD. The engine and transmission are both from a 2004 Impala SS, and I also have (or had...) a PCM from another 04 Impala SS. I have an AVT-852 cable/adapter and RoadRunner (Moates branded TunerCATS). I can't get the car to run using the Impala PCM. I also have PCM's from a 1998 Lumina LTZ (which I was initially led to believe would be the best PCM to use), and a 2000 Grand Prix GTP. *Both* of those start and run the engine (after disabling VATS). The LTZ has a N/A 3.4L, the GTP has the same S/C 3.8L, and both have differences in the transmission that prevent me from using either of them for actual driving. Something about the 2003+ transmissions having fewer/different pressure switches. I've tried so many different configurations and bricked two PCM's (WinFlash occasionally crashes during writes), and can not get this thing running properly.
First thing I tried to do was read the bin from the 04 Impala SS PCM, disable VATS, and flash it back. After a few attempts to find the right value to disable VATS, WinFlash crashed and bricked that PCM. So I tried writing the SS bin to the LS PCM, again trying all possible values to disable VATS, eventually bricking that one as well. In any case with either of those two PCM's (pre-brick), the engine cranks, fires *one* cylinder, and then dies. I then found in Mitchell wiring diagram that the 04 Impala SS has one additional power wire labeled IGNITION, at C2-24 which is hot in ON and START. This is in addition to the C1-19 IGNITION WAKE UP that's present on both cars. C2-24 is not used in earlier years and empty in my wiring harness (which came out of a 98 LTZ). The Impala also has PCM CRANK PWR, a purple wire on C2-23 which is hot in START only, also an unused pin in my harness. I thought I had found the culprit in C2-24, unfortunately I didn't get a chance to test hooking up that new pin to B+ before bricking the SS and LS PCMs.
I'm not sure if writing one bin to a different PCM even works, but by this point I'm trying anything I can. So I flash the 04 Impala SS bin to the 98 LTZ PCM. Again, the engine cranks, fires one cylinder, dies. I hook up C2-24 to B+ and try again. It cranks, starts up and runs for a few seconds, and then dies. Which seems like a VATS issue, so I try all three values for VATS in RoadRunner, 0/1/2, and then all three values again with VATS Injector Disable Time changed from 4 seconds to 0. Changing injector disable time was the only way to disable VATS in the 00 GTP PCM, which I learned from a post on this forum. No matter what, the engine either fires once with C2-24 disconnected, or it runs for a few seconds and dies with C2-24 connected.
I'll attach my bins here, if anybody wants to poke around in them. Stock unmodified bins from all four of my PCM's, and Mod2 is the last version of the bin I flashed to the LTZ PCM.
Am I wasting time trying to get this LTZ PCM with Impala bin to work? Is there something else I might be missing? If any more information is required, let me know!
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