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Discussion Starter · #1 ·
I have a 13 GMC Sierra 3500hd SRW. It has some missing parts and a 150hp single tune in it. I bought it 2 years ago with the upgrades from a dealer. It has been running like a champ until my TCM went out a couple months ago but got one overnighted to me from Dan's Diesel Performance with the Enhanced Tuning in it. When I REALLY get on my truck it will stumble for a millisecond at high RPM but then it will shudder and almost miss fire. The only way to explain it is.... its like having a spark plug wire off a gas motor..

No CEL or errors. I took it to a shop and he tested the injectors and they all were perfect. Checked the fuel rail pressures and they were great. He commanded 21000 psi and it handled it.

The other day I was driving to work and I was really getting on it and it stumbled a couple of times and then shuttered. I pulled off the road and hooked up my ODB2 reader to it with Torque Pro. I could see all data BUT the injectors. It would just shutter and not change. I cycled the key and the truck smoothed out and then the injectors balance rates were reading again.

I got told there was something wrong with the ECM and i would need a new one, with the factory GM flash in it and then get a re-tune for the missing parts. Does that sound about right? I pulled the fuse block off, cleaned the connectors under it, put Grease on the pins and reinstalled it.. still have the issue. I did a Global reset with the batteries and still have the same issue. Still no CEL. Has anyone ever had this problem or heard of anyone having this issue? Thank you in advance.
 

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Never heard of this situation before. Might call someone like John Kennedy, 715-255-9433 . He's one of the best that I know of. I suppose you called Dan's and asked them about it? Just my guess, but it sounds more like a wiring/circuit/sensor situation than ECM to me. Sure would be nice to have a scope on the engine when this happens. Amazing what can be observed with great tools.
 

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Discussion Starter · #3 ·
Never heard of this situation before. Might call someone like John Kennedy, 715-255-9433 . He's one of the best that I know of. I suppose you called Dan's and asked them about it? Just my guess, but it sounds more like a wiring/circuit/sensor situation than ECM to me. Sure would be nice to have a scope on the engine when this happens. Amazing what can be observed with great tools.
Hello. I talked with Dan's and they said they haven't heard of anything like this. I got it back from GM and what they are stating is that the "enhanced tuning tcm" is actually messing with the lockout and staying engaged when it isn't supposed to and vice versa. GM also told me that when that happens it tricks the computer into unloading or loading the injectors with more/less fuel than what is commanded. So I called Dan's and they want me to send the tcm back and they will put a stock file in it but my truck will be down for about a week since I live in Washington state and they are in Illinois.
 
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