Rubikean

Hello all,
First time posting, first time running any gm rig. I am in the final stages of converting my 2008 jk unlimited wrangler to an l96 with 6l80. Its running and driving! Now I'm hunting down the gremlins. I'm hoping to get a little help with the final issues.
The engine came from a 2015 Silverado 2500 with 12 miles on it. It came with all of the accessories, pedal, and e38 ecm. I bought the ac delco o2's front and rear from rock auto brand new and installed them when I had the exhaust fab'ed up.
I have a p0171, p0174 lean condition sometimes with p0300. I am running Efi Live and have several recorded sessions with the dtc. The ltft's are running +24, maf reading about 6 g/ps at idle. The o2 data looks a little odd, but truthfully, I'm pretty ignorant on this. I expected to find a serious intake leak, but was unable to find it using smoke. I was also unable to effect the engine at all with propane, water, and carb cleaner. I also smoke tested the exhaust, but found no leaks.
I have also changed out my k&n air filter with a spectrum filter as well as cleaned my brand new maf sensor. All with no noticeable change. I also have replaced th fuel pump since I got the engine running because of a leaking seal. The only thing that has changed the data is unplugging the maf at which causes the fuel trims to come back to the low single digits.
I can post a couple Efi recording if that would help. I'm not sure how to proceed. I don't have the tools to do a fuel volume test as I've never had to do it before. Is that the next step? Can anyone suggest a path forward? I just don't want to throw parts at the problem without reason. And unfortunately I'm out of insight and knowledge.

Thanks for reading and any suggestions you might have.

-Chris

Edit- moved from gen IV internal engine

2xLS1

iTrader: (25)

Is the diameter of the pipe the MAF sensor is in bigger than the pipe it was in in the 15 2500 Silverado?

Rubikean

I don't think so, I am using a CAI style intake with a maf that is different from the stock one. It is a 3.5" to 4.5" tube I believe. I got it with the conversion kit from Motech in Las Vegas. I have talked to their programmer who check the tune they sent me and said it was correct.

2xLS1

iTrader: (25)

If you are 100% sure the fuel pressure is correct measured with a FP gauge at the fuel rail then the fact that with the MAF unplugged the trims are normal then every thing points to a MAF calibration issue.

Rubikean

Thank you for your input. This is all stuff I am learning as I go.
I just ordered a pressure and volume test kit to verify the fuel delivery and find the injector specs. I'll post up the results tomorrow after the test stuff gets here.
Thanks again!
-Chris