Bank 1 and 2 fuel trims don't match

[Luke77]

The bank 1 LTFT is often about 10% higher than bank 2. Generally it is ocuring at idle and cruising with little throttle. I have been trying to fix this issue before diving into tuning the engine. Is this normal and if not what could cause it?

I have already:
-swapped the O2 sensors side to side, no change.
-swapped the injectors side to side, no change.
-smoke tested the exhaust for leaks, none found.
-smoke tested for vacuum leaks, none found.
-swapped coils, plug wires, and spark plugs side to side, no change.
-verified that the O2 sensors were wired to the correct bank

Engine Specs:
LQ4 with 243 heads and a LS1 hotcam with 1.5 additional LSA.

1.23.20Unchanged.hpl1.23.20.hpt

[5FDP]

I would just start tuning it. You've done just about everything for figuring that out. The tune needs a lot of help when you get into the rpm range, it's going lean on you.

Double check your fuel pressure while you're at it. At idle and under load while driving.

[cobra30689]

In for the info. My 2002 LS1 Camaro does this. Checked high and low for vacuum leaks, intake gaskets are new due to replacing knock sensors. Haven't swapped sensors, but have a feeling that isn't it.

[Gyver-it]

I would look at a mechanical issue since it appears you've eliminated everything else. Maybe try a compression test and a leak down test.

[Luke77]

I have began tuning the VE tables and the issue doesnt seem to be showing up near as bad. It also isnt going lean higher in the RPMs, I think the tune was just quite a bit off. If any of the problems show back up ill look into yalls suggestions and let you know the results. Thanks for the help!

[Luke77]

So the tune is a lot closer to where it needs to be and the issue is definitely still there as can be seen in the log. Is it anything I should be concerned about? I was tuning using my wideband in Bank 2. The log is back in closed loop and shows Bank 2 fuel trims being way closer to 0 than Bank 1.

Test Run.hpl

[Build49]

So the tune is a lot closer to where it needs to be and the issue is definitely still there as can be seen in the log. Is it anything I should be concerned about? I was tuning using my wideband in Bank 2. The log is back in closed loop and shows Bank 2 fuel trims being way closer to 0 than Bank 1.

Test Run.hpl

Flange Gasket Leak.jpg

I see this is an old post but I had a similar problem and this may help others. My fuel trims were good initially (new Cobra Replica build, new engine) but after about 300 km they were out of sync by about 20%. I found a piece of gasket had dislogged from the header collector connection and air was able to be drawn in next to the O2 sensor. I will redo the gaskets with a better quality exhaust gasket material and get back to the MAF calibration. With a Chev Performance LSA crate engine and E87 ECM, the base tune needs calibration with the current intake and exhaust.