I am working on a 04 2500HD 6.0 When scanning this truck, It shows getting 100% throttle opening, IAT at 75, and ECT at 198;but the truck will not go into open loop. The O2's never level out and the truck feels very weak. Where do I need to go first to figure out why the O2's will not level out? Thanks in advance for any help!

 

A lot of the trucks have a PE delay for x number of seconds in the pcm. That's probably what your seeing. A good tuner will disable this so it goes into PE/ open loop right away when conditions are meet.

 

what is the pe enable tps set at?
also set the map conditions low to ensure it kicks in
set enrichment rate to max
you can log the fuel modifier in the PID to make sure its entering PE

 

scanning? what are you using? truck stock? tune been messed with prior to this problem? if it isn't going in to pe/OL, it has no power cuz it's DANGEROUSLY lean. ability to put the tune up here to look at? scans?

 

I would down load a stock bin from Horist site and compair for any changes.
or
Look over Engine> Fuel control> Genral, and closed loop.
If you have positive fuel trim they will add fuel during O.L, also what is your enrichment rate set at under Engine>Fuel Control> Power Enrichment> enrichment rate?

Do you have a log you could post, or send to me at calliedusty@sbcglobal.net ???
I'm no tunning wiz, but there are a few here mybe they can help a bit more than I can

 

Just for the record all you fast typing SOB's.... No one had replied when I started typing....lol

 

I've seen other STOCK 6.0 2500HD tunes that have the Delay before entering PE set to ridiculously high numbers, 60 seconds if I remember correctly. I am almost absolutely certain that is the case in this situation. In EFI Live, it is parameter B3608, should be set to 0.

 

PE Enable Torque needs to be 0%

 

Just checked an 05 and an 03 stock LQ4 tune, both had PE delay at 60 seconds... Guaranteed that is the situation.

 

I'll agree with justin. This is a known problem and was a issue on my Mom's personal 03'. We noticed it right away and realized that the PE was setup to come on after a min!!! Change the PE settings to resemble something sane and noticed a nice power increase.