mcfarlnd

iTrader: (15)

i have been trouble shooting a problem with my ltft for about a month. i am getting a +8 to +15 in b1 while bank 2 hangs out around +1- -5. the wierd part is this only happens from 65-70mph at 1800-2000 rpm in od with the tc locked. if i drop her into third while maintaining this speed it goes away and trims drop to +-2.

heres what i have done so far with no joy

cold air intake checked
new w/b o2 sensor
reprogrammed w/b
new percys manifold gakets(deadsoft aluminum)
swapped o2s (problem stayed in bank 1)
swapped plug wires
checked plugs and gaps
fixed ground on the back of the block(the one on top of block next to cam sensor)
seafoam
swapped injectors
checked pushrods
rechecked the torque on the header bolts(again)

got any suggestions besides a 500 shot of juice to blow this fugger up?

thunder550

iTrader: (70)

Maybe an exhaust leak on bank 1?

Wheatley

iTrader: (12)

Bank1 exhaust leak,check close

mcfarlnd

iTrader: (15)

the only place it could leak is at the gasket at the head (replaced) and the o2 sensor. (ive checked a million times and even sealed it in for extra insurance) both are good. the headers i have place the bank 1 sensor in the #1 primary and bank 2 in the #8 primary before the collector.

thunder550

iTrader: (70)

How far before the collector? It's possible to have a leak slightly downstream of the sensor cause lean readings.

Grumpy5.3

iTrader: (14)

what kind of headers do you have?

mcfarlnd

iTrader: (15)

a good foot or so before the collector. the w/b is directly behind the collector on the same side and it is reading 13s.

aem brute force

i have a log from this morning and ill post it up when i get a chance. im on a work computer.

KySilverado

iTrader: (7)

Possibly a single injector dumping more fuel? Doesn't make sense at a certain spot in rpm range and tcc condition.

My second guess would be heat. NB o2's read different at different temps. Possibly at that rpm range that o2 is getting cold, low exhaust flow, compared to the other. Wrap that collector maybe.

It is not unusual to see one bank vs other with different fuel trims. Don't know if that much.

mcfarlnd

iTrader: (15)

added the log to the main post. dc justin runs the same headers and he doesnt have this problem so, i dont think its the heat. it is kinda doing it in other spots now but, not as much as 55mph and up

BlackGMC

iTrader: (31)

After making a histogram that has LTFT Bank1 and LTFT Bank2 seperated, it looks like you might have a vacuum leak on one side... Notice the difference between the sides... Leaky intake perhaps or a leak around the injectors.... I would log the trims at idle and spray the crap out of it with some carb cleaner and see if the trims change..... Looking at the histogram the problem is across the board, not just at a certain MPH...

VE Bank1 LTFT


VE Bank2 LTFT



MAF Bank1 LTFT


MAF Bank2 LTFT