So I went to start tuning the ecu and...

[Greg E]

Keyan, getting back to your issue with the trims, what's the history of your fuel injectors? Did you purchase them new or at least get them flow tested before installing them?

How old are your narrowbands?

[Keyan]

they are newish sensors. the front bank is an OEM replacement and the rear bank is a bosch universal kit (with the water tight crimps).

it is only my low fuel trims that are weird.

My trims look like this, currently:
Front Low 12.5+ .......Rear Low -12.1
Front Mid 9.57+ ........Rear Mid 1.17+
Front High 1.95+ .......Rear High 1.95+


history of the fuel injectors is nothing crazy, bought them new and have been using them for 50,000 or so miles. PTE.

narrowbands are only about 2 years old, only 60,000 miles or so on them.

i have an fuellab reguator, this one specifically 3SX Custom Fuel Kits - Fuel Pressure Regulator FPR Kits*-*Mitsubishi 3000GT*/*Dodge Stealth Parts. with the fuel pressure set to stock 44 wi@ 0vac. I also am running a simple walbro 255, that is very old. but it seems to be running fine.

[Keyan]

also here is a log from my drive home from work (20 min drive)

https://docs.google.com/file/d/0BxXv...it?usp=sharing

you can see around row 6131 that the ecu tried to adjust the trims by pulling the front bank leaner (from 12.5+ to 11.9+), which forced the rear bank leaner than that (from 12.1- to 12.5-). and then quickly reverted what it did.

[Chris@Rvengeperformance]

I'm not saying this is your problem, but you could certainly eliminate one possibility switching to these

Bosch 13807 Oxygen Sensor, OE Type Fitment : Amazon.com : Automotive

Bosch 13808 Oxygen Sensor, OE Type Fitment : Amazon.com : Automotive

[Chris@Rvengeperformance]

ok I double checked a log. My front and rear lows are a little different, but nothing like you see:

Front Low Trim -4.6056
Rear Low Trim 0.6891

The mids are exactly the same: -4.2134

I am running the o2 sensor above with my 1050s scaled to 1003. I had planned to up to 1035 to get the trims down a little bit closer to zero.

[Greg E]

Keyan. Are you absolutely 100% sure that your front manifold isn't cracked?

[striker2]

I took a log today and noticed something similar to the OP. my front low LTFT is stuck at 12.5 while the rear is at 7.4. O2 sensors have about 10k on them so I dont think thats the problem. I have noticed some back fires out the exhaust during shifts lately and can smell the car running rich. I know that when I rebuilt the engine the front manifold was cracked but I had it welded up. Im suspecting that it cracked again and its causing the rich condition, (which in turn is causing the back fires when the extra fuel hits the oxygen from the crack) along with the stuck low LTFT on that bank.

Keyan, have you had a chance to check your front manifold for cracks? Ill try to check out mine in the next day or so.

[Keyan]

its not cracked, but ill be replacing it soon with a gctech one soon anyway.

ill let you guys know when i yank it this week.

[J-Groove]

Scott, Iceman back in the day on 3Si, had a very similar situation with his AEM setup. I can't remember what the cause was. But he is active on the Facebook boards. Scott Humpert.

Shoot him a message on there.

-John