Boosted Lanch = Truck falls on its face

farm boy · Apr 16, 2013

On a closed course...

I was building boost to do a burnout / launch. Built boost for a few seconds, not sure on the boost number. I let off the brake and mat the skinny pedal.

Truck does a 1 foot burnout then just looses all power like a dead pedal. Rpm's drop off.

I lift wondering what the hell is wrong with it. Truck never died. I mashed the pedal again (not to the floor) and it took off like its supposed to.

Not the first time this has happened. I don't drive like this often, just showing a friend what my truck would do which is apparently just embarrass me...

What do I need to check or look at to fix this?

I dont want to constantly be doing boosted launches while diagnosing my truck.

No access to AE. I do have a scan gauge though. What do I need to watch? Truck has good HPOP pressure and DC%.

On a side note. My cruise has been screwing up lately, not wanting to turn off when I hit the brake or cancel button. Related?

Could this be an issue with my pedal assembly?

Thanks in advance,
Clayton O.

golfer · Apr 16, 2013

IPR nut loose?

or....your torque converter took a chit.

jngreen · Apr 16, 2013

It almost sounds like it tried to lock the converter when you had little traction, and then it caught traction about the same time it locked. Try a 4x4 launch and see if it does it.

David N · Apr 16, 2013

Sounds like the converter did something funny.

I tried pulling last saturday night in 4x4 hi, just to see what happened. Pretty much exactly what you described is what happened. lol Built up, started to move at about 20 psi and then put the pedal to the floor. Then nothing. It bogged the motor really bad.

farm boy · Apr 16, 2013

golfer said:
IPR nut loose?

or....your torque converter took a chit.

Truck runs and shifts good in every other way. :shrug: Pulls really hard through all the gears and runs like a bat outa hell when laying into it out on the street. Ill check the IPR nut just in case.

jngreen said:
It almost sounds like it tried to lock the converter when you had little traction, and then it caught traction about the same time it locked. Try a 4x4 launch and see if it does it.

This is a possibility.

David N said:
Sounds like the converter did something funny.

I tried pulling last saturday night in 4x4 hi, just to see what happened. Pretty much exactly what you described is what happened. lol Built up, started to move at about 20 psi and then put the pedal to the floor. Then nothing. It bogged the motor really bad.

Yep, sounds like the exact same scenario. Let me know what you end up doing about it.

Ill try doing a boosted launch in 4hi sometime this week.

ToMang07 · Apr 16, 2013

farm boy said:
Truck runs and shifts good in every other way. :shrug: Pulls really hard through all the gears and runs like a bat outa hell when laying into it out on the street. Ill check the IPR nut just in case.

This is a possibility.

Yep, sounds like the exact same scenario. Let me know what you end up doing about it.

Ill try doing a boosted launch in 4hi sometime this week.

Given I have a mostly stock truck...but I've done a few boosted launches in 4x4 and never had it stall out on me.

farm boy · Apr 17, 2013

ToMang07 said:
Given I have a mostly stock truck...but I've done a few boosted launches in 4x4 and never had it stall out on me.

Ever since I put the flat bed on a few years ago, I haven't done a boosted launch since the truck never sees the track anymore. That was with an old trans/converter setup though.

This recent trans / converter must not like it.

Wonder if anything can be tweaked in my tunes to not make it do this lockup during a launch business?

Dieselboy. · Apr 18, 2013

You can adjust lockup. But in a sense at wot I prefer lockup as soon as possible while still being ok on the trans.
Usually 2nd at around 10-12mph at wot. I'm not exactly sure how the factory vs my pcs is but I'm sure you can set lockup per gear via mph