gnasty1521

iTrader: (7)

Today I pulled out to go to the gym, and my truck was driving a little crazy, but thought little of it. I was letting the gas gauge dip down so I could figure out how many gallons there was for the tank (it's not the stock tank, or fuel setup), and my transmission was acting up.

Here are the symptoms.

1. Low gas (less than 1/8th tank), traction control / stabilitrak ON. When I hit it, during the 1-2 shift, the traction control would engage and bog the truck seriously. Sometimes it would cut the truck completely off as well.

2. Low gas still, traction control / stabilitrak OFF. When I hit it, during every shift, it sounds like it is bouncing off the rev limiter, but it is under 6000rpm's...

On a try, before I call Circle D, or Nelson's, I fill it up with gas...

1. Gas full, traction control / stabilitrak OFF. When I hit it, it shifts perfectly 1-2, then 2-3 had the rev-limiter thing.

2. Gas full, traction control / stabilitrak ON. When I hit it, it shifts flawlessly through 1-2, and 2-3. Turned it all back off, and everything was fine...

Am I crazy, or did filling it up with gas fix a transmission issue?

Anyone got any thoughts, or had this happen to them before?

Mods are in SIG...

KY_BOB

iTrader: (2)

Possible that it was leaning out due to bubbles in the fuel from sucking some air along with the fuel? Just a wild a$$ guess.

KY_BOB

iTrader: (2)

My other hobby is scuba diving. The science would apply here. Gasses are compressible, liquids and solids aren't. If it were to have enough bubbles in it, they could compress to the point that the pump couldn't maintain the set fuel pressure (on a non-return fuel system, such as a '04-11 Chevy).

Again, I don't know your fuel system, just a thought.

gnasty1521

iTrader: (7)

A viable one... I have no clue why the guy before me wouldn't want the full 26 gallons... On E (Low fuel level light on, and indicated) I got 21 gallons in.

KY_BOB

iTrader: (2)

Just second guessing GM, as we have done in another thread, maybe they want to make sure that they never have to let you hit the "onstar" button and say "I'm out of fuel".

It's plain as day that they are over-conservative. I have licensed my HPTuner to my truck. I've yet to make a change to it but I have looked at the tune. The high octane table on my truck, which is based on E85, is more mild than what I ran on my boosted Avalanche.

I'm not familiar enough with the newer tunes to play with it myself, yet. I think I'm going to get Allen Nelson to email me a tune as a starting point. It cost about the same but I can tweak little things, like shift points, if I want and I have my stock tune saved. It can be flashed back in if it has to go to the dealer for warranty work.

gnasty1521

iTrader: (7)

That's the thing. It is tuned by Nelson Performance. I am wondering if it got too lean, but then why the traction control light on the 1-2 shift? And when I turn it off, why does it sound like it is hitting the rev limiter? Just crazy.

2007chevy5.3l

iTrader: (21)

Id have him look over the trans tune some...

gnasty1521

iTrader: (7)

This almost leads me to believe that if the truck senses a lean situation, it avoids damage by turning on traction control, not just tire slip. These things are very computer oriented. I will update tomorrow to see if it was a fluke that the gas fixed it. I may take a trip to San Antonio to try to dial in the trans tune again though either way.

Atomic

iTrader: (42)

There is no sensor to sense a lean condition, unless they put factory widebands on these trucks (not too unreasonable, the turbo cobalts have them).

ig109

Man that truck you bought sounds like it has had WAY too much work done to it...

Why in the hell would you change the tank and fuel system on these things. I could see the whole pump upgrade thing but come on..