Lean at WOT???

[Paulster2]

Only two things it could be IMHO and both pertain to fuel.
1) Injector size
2) Fuel pump not keeping up

You need to check to see what your injectors are doing and make sure you haven't maxed them out (I doubt you have). Secondly, check to make sure you have the fuel pressure you need at WOT. You can check this by attaching a fuel pressure gauge at the Schraeder valve and placing it in a position OUTSIDE OF THE CAB where you can see it while driving. Check to see if you start losing fuel pressure at WOT. If so, I bet it's your pump.

Just some suggestions, but do as much diagnostics as you can do before you start replacing parts. Gunna save you a bunch of money in the long run.

[sprayedenali]

Only two things it could be IMHO and both pertain to fuel.
1) Injector size
2) Fuel pump not keeping up

You need to check to see what your injectors are doing and make sure you haven't maxed them out (I doubt you have). Secondly, check to make sure you have the fuel pressure you need at WOT. You can check this by attaching a fuel pressure gauge at the Schraeder valve and placing it in a position OUTSIDE OF THE CAB where you can see it while driving. Check to see if you start losing fuel pressure at WOT. If so, I bet it's your pump.

Just some suggestions, but do as much diagnostics as you can do before you start replacing parts. Gunna save you a bunch of money in the long run.

a friend of mine has a stock fuel pump and 28lb (maybe 32, cant remember) injectors supporting well over 500whp FWIW...

[chvy=power]

hook the fuel pressure gauge up and run it up to the windshield and shut the hood till it latches but not all the way. that way you can see the fuel pressure at WOT while your goin down the road. And if your running that lean be careful at high rpm its not good on the motor

[iowackers]

Finally went for a ride today with the fuel pressure gauge. 50 psi at idle. Very responsive with throttle movement. WOT was 58 psi. Truck still feels weak and at 5000rpm it dropped out and went really lean again (19.2 AFR) No codes. I have gotten 1 or 2 O2 codes in the last couple years, but that is all. Any ideas? Check injector duty cycle next?

[pl4yboy]

Finally went for a ride today with the fuel pressure gauge. 50 psi at idle. Very responsive with throttle movement. WOT was 58 psi. Truck still feels weak and at 5000rpm it dropped out and went really lean again (19.2 AFR) No codes. I have gotten 1 or 2 O2 codes in the last couple years, but that is all. Any ideas? Check injector duty cycle next?

Yes. IDC next. It may not show a clogged one though.

[Paulster2]

Do you have a tune on it? Was just thinking there might be a flaw in the tuning when you hit WOT. Especially since you are showing your fuel pressure to remain good at WOT.

[iowackers]

I have no way to check IDC currently. I am contemplating buying HP Tuners. Will HP show this?

[iowackers]

Yes I have a tune from Nelson. He recommended I check the fuel pressure before he disects the tune any deeper. I have been in contact with him. There customer service is AWESOME!!

[farmtruc]

a friend of mine has a stock fuel pump and 28lb (maybe 32, cant remember) injectors supporting well over 500whp FWIW...

statements like that are so misleading, a cam and headers will max out the stock setup on 6L's.
we do fbodys all the time here, a big cam and headers maxes out the stock 28lb injectors.

doesn't sound like a safe setup, at well over 500hp...

To the OP, if there's anyway to get logging going, send it on over, that'll help quite a bit.
Typically, with a cam like that in a that engine, with longtubes, we can keep a/f ratio in check.
Maybe the injectors are a little dirty/slow and you need bigger ones, or maybe we just need to add more fuel to the engine.
If it is out of injector, trying to add more fuel from a retune isn't going to work.

lmk,
allen