Slow response 1st gear...Issues?

[mike diesel]

Been dealing with this for about a year. It did it on the stock motor and it still does it with the built motor, did it with my old trans and still does it with my new trans. It all started the day after I put my dual cp3's on. 100% confident it is not tuning related because I have tried 2 or 3 tunes that all never did it before that all now do it.

Here's the alleged issue...

Normal driving, everything is fine...Non boosted dead stop foot to the floor the truck will accelerate at what feels like a very sluggish rate as if it is not fueling, pulls through the rpm range, shifts at 3700rpm and 18+ psi boost, hits 2nd gear and as if a light switch was turned on the power hits instantly and the tires blow off.

It never did this before...foot to the floor, it would take off and blow the tires off mid 1st gear, shift 2nd and keep going.

Installed dual cp3 April of 2014. Drove for a day on my smaller single cp3 tune, all good. Flashed the new bigger tune in and it ran awesome. No problems. Parked the truck for 3 days, hoped in that Friday to head to the track, and that's when I noticed it.

The maf is scaled aggressive because that's the only way to make it somewhat better. I've even tried a new maf with no change. Scale the maf back and it is far worse and more unresponsive.

If i 4x4 boost launch, the issue doesn't appear to show itself.

What can I look for that may remedy this? There is no codes and the logs look good. I pawned it off but now it's starting to annoy me again.

Here you can see it. Floored in 1st at a 10 mph roll.

https://youtu.be/8GNdTeCF-Do

Dead stop floored, clicks second and blows the tires off.

http://youtu.be/62XJtAmX6E8

4x4 launch...all good.

https://youtu.be/83OQCgBFzvo

 

[mike diesel]

Last year trying to figure this out i checked wiring and seemed like i found power was being backed onto the ignition 1 circuit if i remember correct. Found multiple wires that had been chafed through and repaired them with no change. Pulled my fuse box and found d a rat had made home under there and chewed about half a dozen wires and completely chewed through 2 of them. Fixed those as well and noticed zero change.

Would a bum cp3 controller cause an issue like this? I haven't had an opportunity to try a different one. Maf seems to be working perfect, rail pressure sensor works fine, bar sensor, map sensor both work fine as well.

Valley cp3 is my stock original one with a fairly new lbz regulator in it, 2nd cp3 is a rebuilt pump with a brand new regulator in it. Had it tested about 2 months ago and it tested perfect.

 

[LbzDMax07]

So it ran ok with dual fuelers while still on single cp3 tuning?

 

[mike diesel]

Turbo back then was a 72/83/.90. Turbo was not swapped.

And since then I have swapped from the stock stall precision ml converter to a 1055 and now to a 1053. Turbo has gone to an 80/83/.90 and now a 72/87/1.0, all with zero change.

 

[mike diesel]

So it ran ok with dual fuelers while still on single cp3 tuning?

I drove it maybe 10 miles that way before new tune was flashed. Drove around for a day on new tunes running great like it always did. Parked for 3 days, fired it up and that's when I noticed it. I flashed old tunes back in to see if it was a tuning issue with no change. That is why I'm positive it is not tuning related. And since then I have had probably 5 revisions flashed in with no change.

 

[LbzDMax07]

It sounded like a tuning issue but if you flashed back then I don't believe it is now.

 

[mike diesel]

It sounded like a tuning issue but if you flashed back then I don't believe it is now.

I flashed all the way back to my vvt days. Doesn't matter what tune it is, still does it.

I don't have a clue what to do, everything seems to check out good.

 

[quinton]

Does it do the same thing if you are in second gear and punch it or any other than 1st?

 

[mike diesel]

Does it do the same thing if you are in second gear and punch it or any other than 1st?

No, only first gear as far as I can tell.

 

[WolfLMM]

That's odd, but boy does that thing run out nice:thumb:

 

[Ridin'GMC]

Did you have the tune checked out if there is a torque management limiting it in 1st gear?

 

[mike diesel]

Did you have the tune checked out if there is a torque management limiting it in 1st gear?

Yes he's checked. And the fact it does it on tunes that I know never did it..

 

[PureHybrid]

Sounds like you should log desired rail and all that bs

 

[Forever]

I have nothing to add or help you with your issue, but those videos made me jelly. :angel:

 

[Wake]

I have a 2004.5 lly and my truck acts exactly how you described also. If I stop and then floor it I go nowhere my truck seems to just take its time until all of a sudden then it runs hard. This only happens from a stop, if I am in any other gear than first and get on it power is instantly there.

I have read a lot under torque management and dead pedal.... I don't have a lot of knowledge about these trucks but I thought I would share. If you find anything hit me up I would like to know also.

 

[DIESELMAFIAPER.LB7]

Turbo lag...... mine does it to

 

[Wake]

I don't believe it is turbo lag it feels like it is holding back. I feel that I am limited somehow if I'm just barely rolling and get on it I can't seem to keep the tires planted but if it's just from a dead stop I have no power

 

[Ridin'GMC]

Did it do the same issue in both 2 & 4wd on a boosted launch?

 

[coker6303]

Looks like lag to me... "spools like stock". Lol

Dirty too. May be throwing too much fuel too quick with no real load in first gear. Justt thinking out loud.

 

[minerigger]

4600 ft and a big single...I'd say lag. This is why my 366 came off. I didn't like that part of it