Turbo 4.8l Lean spike issues

[czipar27]

First off, i am working with a turbo 4.8l silverado bigger pump and injectors from fuel injector connection (cant remember the specs currently) but all the data came with and is correctly entered into the tune.
engine is 100% stock except for colder spark plugs.
running MAF only OL tune with 6-7psi
everything looks great and runs great threw a quick pull, but after an extended period of time (while in boost) i see a lean spike that holds until i let up on the throttle. fuel psi is good via a manual gauge holding steady the whole time. i am stumped.
what could be the cause of this? it will do it consistantly on long pulls (in boost)
PS it is staying in PE
tune and logs attached.

All help is great,
Thanks
Turbo_v1.7.9.2.hpt
hill lean spike 2.hpl
uphill pull Lean spike.hpl

[5FDP]

I would ditch the MAF sensor and run speed density on that setup, less problems for sure.

You have no way of seeing boost with a 1 bar map and stock VE table.

[czipar27]

Since the truck is a daily driver, I'm trying to utilize the maf. I appreciate your input.
I would really like to solve this issue.

[turbochevytruck]

upgrade to 2 bar COS. You are goin to hurt something playing with the 1 bar map

[5FDP]

You can daily drive a speed density setup the same way you did when it was stock. You can still run a closed loop system with ease.

You are limited by the MAF sensor (won't take much boost to max it) and running MAF only a turbo setup with no way to measure boost and not having a VE table setup for boost isn't helping. It still trys to use the VE table even if MAF only mode for transient fueling.

[czipar27]

I understand what you are getting at, but I'm not having any transit issues. I do not see why this won't work tuning maf only. I am not maxing the maf out with 7psi and as I said I do not plan to run any higher boost.
What about this is playing with fire when the truck isn't using the ve table anyhow?

[czipar27]

Fixed,
The ecu was seeing a large diffrence between the MAF and Dynamic causing it to revert back and use the VE table for fueling. Multiply VE by 1.3 and Boom. fixed.
Truck is running great on MAF only.

[5FDP]

But in reality it's not fixed, you still can't measure boost with how you have it set up. All you did was fudge some numbers and lie to the computer.

It would be wise to switch how you are tuning it but hey it's not my engine.

[czipar27]

Actually I do have a 2 bar sensor in the truck and I can monitor boost with it. It's rather simple.

[5FDP]

You should be running a 2 BAR operating system so you can correctly use the VE table, among the other features it offers.