batmanntexas

iTrader: (1)

Hello All! Okay, I just moved from Albuquerque, NM (5500ft) to Sanford, NC (350ft). I keep getting P0171 and P0174 codes. They show up about every third/fourth day of running the engine, and they usually pop when the car is in steady state cruise. I have an UltraGauge scanner that I have set to monitor STFT's and LTFT's. The STFT's are usually between 0-5. The LTFT's, however, are around 15-20. I'm guessing the LTFT's are telling me that the computer is adding 15-20% more fuel to compensate, thereby triggering the P0171, P0174 codes. Correct??

The car is scheduled to go to a local shop for a data logging session on the dyno on Tuesday. I just can't sleep well wondering if I might have other issues?

The car has the following mods: Custom tune, Whipple, 3.75" pulley, LS9 camshaft, 1-7/8" LT's, full 3" exhaust, AlkyControl Methanol kit running smallest nozzle @100% Methanol (tune is not calibrated for the methanol, just running it for safety).

I have already checked for vacuum leaks as well. Thanks for any help,

Scott

batmanntexas

iTrader: (1)

Bueller??

Pro Stock John

iTrader: (34)

Long term fuel trims sound high to me, they are supposed to buffer the short trim changes but if your long trims are always kinda high it sounds like some tuning might be needed.

I don't know those codes off top of my head what are they?

batmanntexas

iTrader: (1)

@Pro Stock John: Thanks for the reply. Yep the data logging session confirmed that the computer was adding approximately 20-25% more fuel to the programmed tune to compensate. Got the tune re-calibrated, now the LTFT's are around 1-3% range.