E38 Truck cant figure out lean spot..

[thunderbolt]

I am working on a 2008 Truck for a friend which is not running right and i cant figure out why
It has some really rough spots, especially during rapid throttle changes. The O2's falls on their face and the truck hesitates really bad.

The truck originally had a 5.3 but a 4.8 is swapped in. All tables are copied from a 4.8 file so it should be right.
I have messed around with PE and burst knock to get it to react better, but very little results from this.

I have not touched the "VE" or the MAF tables because in theory it should work as stock.

Hopefully someone have some ideas?

The tune and a short log attached:
Rune silverado 2008_NY_shift2burst knock.hpt
Ny test4.hpl

[thunderbolt]

One more log. As you can see, when I mash the throttle it falls right on its face and slowly accelerates. O2's show almost 0.
I know a wideband should be used, but the engine is stock so it should not be such a big issue with the tune...

Ny test3.hpl

Could it be the transmission abuse mode that is kicking in? I cannot find the PID for logging that...

[kevin87turbot]

See if this does the trick. S0metimes the VVE tables will get you when you do a swap like this. They either need to be calibrated or disabled.

Rune silverado 2008_NY_modified.hpt

[thunderbolt]

I tried to run it in MAF only like your tune earlier today and it did not work really well so I suppose I will have to tune both the VVE and the MAF but I just cant understand why.
I have not tried to mess with the tip in limiting so I will try that. I also see that you enabled Injector Gain. I am not familiar with that table, what does that do?
Thanks !!

[thunderbolt]

This is strange - the truck runs well in pure MAF and it runs well in pure SD but together it has the hesitation. I am guessing something is not right with dynamic airflow predictions because the issue is just with rapid throttle changes - not if I slowly change throttle levels. Problem is - I have checked these settings with several other stock files and they are identical so I am really stumped here....

[lukearmstrong1990]

disable injector desoot mode (right down the bottom Engine>fuel>general)
disable both switches and max tables for fast torque exit
disable burst knock (knock retard will correct it if its real)

if you wish to run SD no MAF max out the dynamic enable RPM so it doesn't go looking for a MAF during rapid throttle application (engine>airflow>dynamic)

[thunderbolt]

Thanks. I will try this tomorrow. I really do not want to run just SD because this is just a 100% stock engine for street use.

[thunderbolt]

No luck with this. Truck still has a really bad hesitation when I change the throttle rapidly.

I did one log with the MAF failed and one with the MAF enabled and you can clearly see the difference under acceleration.
With the MAF it falls on its face and the O2's read zero but in SD mode they go rich immediately and no hesitation.

I just cant figure this out

[wasyl]

leave MAF calibration stock and just play with VVE, had same issue when swaping stock 5.3 to other car. For unknow reason PCM is not able to work propperly in SD/MAF mode, but in only MAF or only SD mode runs ok. i'm gonig with SD only because if You get any vacuum leak that is hard to trace or MAF is failing but no codes this my happen and You'll never be able to set it right. in SD mode vacuum leak is not and issue for propper fueling, only in getting propper idle and getting a bit of dirt thru that leak.

best regards

[sevinn]

Zero out your prediction coefficients.

[lt1z350]

Possible mechanical issue. Check for vacuum leaks leak post maf check pcv stuck open pulling to much air. Being an engine swap it leaves you open to stuff like that. Also did you use the same maf as the other any other sensors look at everything. On my 6l80e swap i had found this 09 harness had the pins backward for the maf so it bbq the temp sensor in it. So on the swap look for things you might think are ok. Might find a leak and too much un metered air.
Also what’s the combo n/a cam turbo blower anything other then stock?