LS3 - 408 Popping - 6L80e not shifting ....

[6600DURAMAX]

Having two separate issues

1. Have a Blueprint LS3 - 408 - makes 595HP engine almost 400 at the wheels - running a PSI Harness and a 6L80e trans - full length headers into dual 3'' stainless exhaust with "X" pipe and 3'' BORLA ATAK mufflers. Engine has about 500 miles or so - oil changed since break in also installed new plugs and Scott's Performance wires.

Question that I have - when accelerating at roughly low to mid throttle input the engine wants to pop through the exhaust - this is especially noticeable right before it shifts. Been to the tuner twice and he states it is not running lean and that it is impossible to tune it out 100%

I'm at a lost here - thoughts suggestions.


2. Have a 6L80e behind a LS3 - 408 - the transmission has a Yank Pro Truck 3200converter in it and is being controlled by a PSI Harness

Question - if I am driving the truck normally - the trans shifts normally ( all the way into 6th gear). However if I accelerate hard, do a burnout, ect..... the trans will not shift all the way into 6th - seems to shift to 5th and just stay there. If I stop and shut the truck off, restart it and take off all seems to be normal ??
The other day the trans wouldn't shift out of 2nd gear( I think it was in 2nd) ....... drove for a mile or so - shut it off.... restarted it... all seemed fine and shifted all the way to 6th

Ideas on the cause of this ??

Any help on either of these issues ???

[6600DURAMAX]

everyone loves pics ....

[Willie Makeit]

I would find a new tuner

[RustyPile]

Originally Posted by Willie Makeit

I would find a new tuner

That's also my suggestion.......

[6600DURAMAX]

I don't disagree with you guys - its odd however as I've known this tuner to be super reliable per a bunch of people

Anyone know a tuner in the Northwest Indiana area ??

LS3/ 6L80e with a PSI Harness

[6600DURAMAX]

Here is a plug I pulled

[Accelo]

Maybe this will help, some transmission tuning information.
https://www.youtube.com/watch?v=8PCjGINa100

Full throttle in 6th gear? I don't know your gear rations, but the speed has to be very high. Will the Blazer do 160mph?

You have an absolutely gorgeous Blazer.

[6600DURAMAX]

I'll try to clarify the transmission question - I'll watch the video, appreciate it

If I am driving the truck normally - the trans shifts normally ( all the way into 6th gear).

However if I accelerate hard from a stop ( 1st gear maybe 75% throttle) the trans will not shift all the way into 6th - seems to shift to 5th and just stay there. If I stop and shut the truck off, restart it and take off all seems to be normal ??

The other day the trans wouldn't shift out of 2nd gear( I think it was in 2nd) ....... drove for a mile or so - shut it off.... restarted it... all seemed fine and shifted all the way to 6th

[LS short box]

No help with the 6th gear issue but if you duplicate the 2nd gear issue with your tuner in the vehicle with his laptop plugged he should be able to see? the issue.