Hey all, my tuner and I are stumped. Here is the the rundown, 99 cobra with a terminator swap. I have the 99 PCM. 2.93 upper, 4lb lower, 60lbs injectors, K&N FIPK. The issue that we have run into is that when we are on the dyno the bank 2(driver side) o2 sensor starts going super lean at 2300rpm and maxes out at 2500rpm. This only happens when in closed loop mode. We thought it would be an intake leak but if we turn off closed loop mode and go through the entire rpm band it never leans out at all. Which it should if there was a leak. Now we have swapped fuel injectors from left to right, put new o2 sensors in, put known good o2 sensors it, compared it with a wide band, I've checked voltages down the entire o2 harness, and ruled out exhaust leaks. I really hope that it isn't a PCM issue. The car runs and drives great if its forced into open loop, no misses, great power smooth and everything. When we put it in closed loop the car has a terrible miss and bank 2 goes crazy lean (19.5:1) but again, this only happens at 2300rpm and gets worse. At idle and up to 2300rpm everything stays right together and acts right. OH! and it only happens under load. If we leave the car in neutral we can rev it to the moon and it never goes lean.
So, short story long, lean at 2300 only in closed loop and only under load and only on bank 2. Bank 1 works perfectly.
I know I haven't made a lot of sense with this, hopefully someone can understand my crazy writing. Please help.
So, short story long, lean at 2300 only in closed loop and only under load and only on bank 2. Bank 1 works perfectly.
I know I haven't made a lot of sense with this, hopefully someone can understand my crazy writing. Please help.
