Bank 1 vs. Bank 2 differences?

[VetteNut]

In the absence of vacuum leaks, using flow-matched/balanced injectors, plugs/wires good, no misfires detected (Tech II Scans), etc., what could cause:

From scans:

O2 sensor readings to be way off from bank to bank. In some cases, bank 2 reads 0 while bank 1 is reading about 900mv, but not all the time.

Injector pulse width is off with differences between 1 to 2 points (Bank 2 higher than bank 1).

LTFT's are 0 to -8 on Bank 1 and as high as 25 on Bank 2.

SFTF's also showing even larger descrepancies between banks.

Besides a lame Bank 2 O2 sensor, any suggestions on where to focus attention to resolve this?

Car is a Corvette with a 427, LSX/90mm LS2, AFR 225 heads, cam, Supercharger with 72lb (Low Impedence) injectors.

[Throttle]

join the club with widebands in both banks its the same my bank 2 is different.i have 0 LTFT's on B1 and 5.5 on bank 2 .flowmatched injectors and i took the intake off today and fixed all leaks.helped a little.

[chrisj6]

First you are going to have to replace that o2 sensor, if not both just to rule that out. Just swap sides with the sensors and see if the problem follows. If you have no leaks and have flowmatched injectors, then that is ruled out and you have to look at the o2's. You are going to have at least a .5 difference, one bank is ALWAYS leaner, no matter what by a tiny amount.

Chris

[VetteNut]

It was in fact the O2. Unfortunately with 1 7/8" headers it was a PITA but that cleared up a number of problems. Still a cheap fix for lots of bad things.

Thanks...