2007 Sierra dead after tune....

littleblazer

Original poster
Member
Jul 6, 2014
9,265
Followed the link and traced wires all morning, also ohmed out the throttle body at closed and open, no short. Rechecked the pcm wires, no viable broken or frayed wires so I don't know
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
Did you check the pedal sensor? If you have a local u-pull yard, maybe pick up a pedal sensor and throttle body and swap them as they may be related to the problem when going WOT.
 

littleblazer

Original poster
Member
Jul 6, 2014
9,265
I couldn't get the plug removed from the pedal sensor. But I traced the wires at the under hood module I guess? And there were no shorts. I have a couple more things to check tomorrow.
 

littleblazer

Original poster
Member
Jul 6, 2014
9,265
The dealer won't touch the truck because it has a tune. Is that some B.S.?
 

Sparky

Member
Dec 4, 2011
12,927
Uh, what does that matter, the throttle killed the PCM anyway...

Did you tell them it has a tune or were they able to figure that out?
 

littleblazer

Original poster
Member
Jul 6, 2014
9,265
Sparky said:
Uh, what does that matter, the throttle killed the PCM anyway...

Did you tell them it has a tune or were they able to figure that out?
The first words out of my dad's mouth were tune, and they didn't want to hear it. But what does that matter you know?
 

littleblazer

Original poster
Member
Jul 6, 2014
9,265
A friend is a friend of the gm tech for the nj turnpike fleet. Going to talk to him...
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
Or just go to another dealer and don't mention the tune. Unless they dig deep, they won't know and won't matter.

Since you mention "dad". does he go WOT once in a while or does he drive it like an old man? If it's the latter, then the condition could have existed before the tune, then you floored it and BAM.
 
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littleblazer

Original poster
Member
Jul 6, 2014
9,265
Let's put it this way, the truck is a work truck, he wants to be done quick, it is floored every chance he gets, trust me when I say he drives it hard, and he takes most people off the line because they never expect it. But at the very least, it's floored twice a day 6 days a week for the last 143k.
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
Maybe that's why it's having problems at WOT :biggrin:
 

littleblazer

Original poster
Member
Jul 6, 2014
9,265
Never used to. [emoji6] Funny thing is even with 9000lbs behind it, it will still beat the trailblazer in a straight line and around the turns, that truck is tight. But it's been well maintained and almost never driven in the winter. No frame rust. But yea it had a hard life, but it's loved. [emoji2]
 

littleblazer

Original poster
Member
Jul 6, 2014
9,265
Update: the truck can be beaten on with the factory flash. So that should rule out frayed wires and anything like that.

So it's something that's changing with the tune...
 

littleblazer

Original poster
Member
Jul 6, 2014
9,265
Update2: Since driving around with the truck, we've noticed something at night that we never noticed before, the truck is rarely driven at night. Under hard acceleration the alternator stops charging, voltage according to torque drops to battery level, about 11.7. This is weird, anyone ever expirence this before?
 

Mounce

Member
Mar 29, 2014
13,667
Tuscaloosa, AL
I've heard of alts protecting themselves by stopping charging when they get above a certain rpm. Don't know if that's what's going on with you or not though.
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
I have, on a dying alternator.
 

littleblazer

Original poster
Member
Jul 6, 2014
9,265
Alright, I'm going to look for the receipt this weekend, I don't even think the thing is a year old.
 

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