Bank 1 LFTS 25%, Bank 2 LFTF -3.9%

[Minglor]

(typo in title, not sure how i did that, "LTFT" is the correct word)
trying to get my swap running.

mods are lq4 block with stock pistons
243 heads
stock intake mani and TB (DBW, pedal, tac module, TB, PCM all match from same vehicle)
headers
TSP 228r cam
BTR .660 springs
7.375 pushrods
ls7 lifters
New primary O2's (rear o2, and all other emissions turned off)

harness is a modified stock harness to run standalone.

LTFT.PNG

heres my LTFTs, at idle. AFR goes super lean and is intalled on the passenger side a few inches behind the O2.

any ideas?

[5FDP]

I know thats just a screen shot, but both o2 mv are stuck at 447. I'm not saying they arent swtiching, but I'd look there for sure. If they don't swing back and forth from 100 to 900ish mv, then you have a problem there.

[AutoWiz]

it's been my experience that usually differences between bank 1 and bank 2 are not tune related as there is not much in the tuning software that lets you make changes on individual banks. maybe a vacuum leak at a intake or header gasket, or a fuel injector unplugged or not spraying, or something that could cause a really lean condition only on the LH head. that is where you should be looking.

[CRTD]

+25 LTFT = vacuum leak if only at idle, lean fuel injector or exhaust leak near O2 if all the time. 1st things to check.

[badco01ta]

also to add to items to check is potential bad sensor, bad plug at sensor or burnt wires. as with a bad sensor it defaults in the computer to add max fueling to maintain a safe working enviroment

[Jay@HAP]

As mentioned the 02's "look" like they are stuck lean in that screen shot. Also if that wideband PID is accurate it is actually lean.

[Minglor]

Heres a log from yesterday with those wacky fuel trims, and you can see the o2 mV readings do opposite things. with this log, the passenger bank was very lean, confirmed with a plug pull, and the driver bank was rich as discovered by pulling a plug

stock tune with injector mod, closed loop o2 off, fuel trim learn off.hpl

so i reset the LTFT, and then turned off closed loop and turned off fuel trim learn. heres the log i got. AFR is much more reasonable.

stock tune with injector mod, closed loop o2 off, fuel trim learn off.hpl

with that in mind, im thinking my o2 wiring is wrong when my harness was reworked to run as a standalone. it would appear the bank1 and bank2 are flip flopped, am i correct in this thinking?

[Minglor]

Got this issue sorted. the o2 in the passenger side was in the PCM location for B1S1. and the o2 in the driver side was in the location for B2S1. this is backwards.

so for any one else with this issue.
Pin 26 and 66, switch with 29 and 69. these are the pin location on the blue PCM connector for a 2004 lq4 harness.

[AutoWiz]

That would definitely create different fueling on each bank.

[chevypower101]

mines the same way bank 2 is lean like 3.9 when other one is like 1.6 my intake manifold is the case on mine and if yours is still oem gasket good chance its leaking