I am told I need a new PCM

[gtstorey]

I've had as good luck with walmart batteries as with anything else.

[tRidiot]

Well, I am screwed. I went to a few salvage yards and managed to pull an ECM, from a 5.3L Yukon, so it would need a 6.0 tune, but now I cannot find my MPVI2+. That tiny little box has gone missing sometime in the intervening 2 years. I found the stickers and the registration and sync paper on my desk, the lanyard and a big black rubber band with HP Tuners on it, so I know I opened it up, I probably connected it in my truck at some point 2 years ago just to see if it worked, but never programmed anything, as the 2 credits I bought are still assigned to my HP Tuners account and unused.

But the actual programmer itself, totally AWOL. Not on my desk, nor anywhere in the mess or clutter or boxes that are my office, not anywhere I can find in my garage, kitchen junk drawers, nothing.

So now, I guess unless I buy another MPVI3, or something, I'm out of luck trying to program this ECM myself.

What happens if you try to put in an ECM with a 5.3L tune into a vehicle with a 6.0L motor? Will it not run at ALL (as in not even start or idle properly), will it actually physically damage something, or will it run like total shite, or just run somewhat poorly? I'm not about to try it just to find out, I am just wondering, is that an option?

[2xLS1]

Ship me the PCM and I'll get it set up correctly for what you have. Just pay for return shipping.

[tRidiot]

Ship me the PCM and I'll get it set up correctly for what you have. Just pay for return shipping.

That is incredibly generous of you! I would be more than grateful for that! I can throw you a few bones... I'll PM you. Thanks!

Maybe my MPVI2+ will show up someday in my digging around and I will be able to tinker in the future. At the moment, my truck has been out of commission for something like a month, so if I can just get it running I will be on cloud 9 - for a little while, at least!

Thanks! PM inbound...

[SiriusC1024]

Yeah that is awesome, 2xLS1.

[2xLS1]

I have his original stock file from his vehicle when I programmed it in 2012 so it will be easy to straighten out his issues.

[tRidiot]

W00T! I'm hoping this fixes all my problems and things will just RUN. I'm not looking for huge performance gains here or anything, I just need to keep this truck limping along a few more years. Since spending $8k+ on a rebuilt motor and trans 2 years ago, I need to keep it going. Got too many other things that need paying off before I can even think of buying another vehicle just for me.

2xLS1 is the man.

[weinerschizel]

Haven't read all the way through. I flashed a PCM with a new tune was dirt cheap as the P01 and P59 PCMs are a dime a dozen. You have to build a cable (YouTube it) and use PCM hammer. Do it on the bench (not in vehicle), you download your good PCM and flash it to the new PCM. You cannot do this without buying a bunch of credits and jumping through hoops with HP Tuners. Otherwise, I think GM OEM software can do it but would be extravagantly expensive. This was thread where I did all that... If I was at home I could flash it for you but I'm on the road.

https://www.tahoeyukonforum.com/thre...4#post-1809190

I'd check the wiring harness before I go to all this trouble though. Mechanics can be really lazy about that at times. Make FOR sure the harness is good or you could be right back doing the same thing.

Additionally, you should have a separate box just to control that throttle. the TAC? I cannot recall exactly what it's called. That's how my 1999 Corvette is setup. It's possible the Throttle Controller box is messed up.

ELECTRONICTHROTTLECONTROL-1-2882038650.jpg

And scan your PCM for codes. If you are tuning you should know how to do this no? At least have the parts store scan it.

Also, don't baseline like that you want to compare at least to your original tune (old 5.3L engine) as truck came with for your drivetrain / chasses. That LQ9 tune will not be and could lead to little gremlins like this. You need to compare to your original config that came with the original motor / chassis. If you don't have that anymore you may like to download an LM7 (I assume that's your original motor) factory tune and compare the throttle settings to what you have.

I built up a LQ9 and swapped out my LM7... My baseline tune is still the LM7 tune. I have a LQ9 config which I pick and pull things from from time to time but I didn't just rebaseline with the LQ9 as the tune isn't just for the motor. It's setup for your trans, driveline and chassis as well.