Car: 2000 Viper on JTEC, Supercharged, SRT4 2 bar map, larger injectors, fuel system converted to a return style system.
I have been struggling to resolve what appears to be a Altitude (BARO) compensation issue in this tune and was wondering if someone could review what was done and make some recommendations. The car was originally tuned with the Altitude compensation table left at the default values and the MAP thresholds lowered so that (I assume) it would not throw a code for an out of range MAP value on the 2 bar MAP replacing the 1 bar. After a hard pull the BARO would shift upwards (relearn) leaning out the engine. I thought I could compensate this by pinning the scalers in the Altitude table to the high altitude values so that as it shifts upwards, the multipliers would not change. However, the car still appears to be leaning out at light throttle. I am not sure if I need to redo the entire tune with more base fuel and 1 out the Altitude table, or if there is some other scaler that is forcing the trims to skew so far negative. Here is a tune where the car was running really well, then as soon as I get on the highway after doing a hard pull the LTFT and STFT pogo between +20 and -20% at light throttle. Any thoughts would be appreciated.
Turning off the Baro Learning is Boost tuning 101. Do that first.
This is done to keep Baro from updating to a value far above normal. But your Baro is reading far lower than it should be. That makes me think you MAP sensor isn't scaled correctly.
Srt-4 MAP are 2.27 Bar with a slope of 46.38 KPA/v. i'm not sure how that translates into JTEC-eze. Key ON engine Off, read MAP and BARO and make sure they're both reading around 100kpa/14.3psi. Unless you live on a mountain, it should be close to that
Also, Don't sweat wonky Fuel trims when your sensors aren't even reading correctly.
Reply With Quote