Fuel economy
Nov 11, 2008 | 07:54 PM
#31
That is correct, mine are all 1-2%... IMO since your running in closed loop, I would recommend tuning your cruise cells (part throttle) with fuel trims (STFT or LTFT) instead of your wideband... There might be a small difference between the two, at least from my experience... Since your running closed loop, you might as well tune with the trims cause that is what is going to be controling your fueling when your done anyways.....
Nov 11, 2008 | 11:20 PM
#33
if i try lockin mine up that soon it bucks like im rolling gangster with hydraulics.(insert vato smiley here)
Nov 12, 2008 | 07:24 AM
#34
Have you tried dropping your Rich/Lean Voltage of your 02 sensors for both Bank1 and Bank2 to something like 375mV (HPTuners > Engine > Fuel Control > OL & CL > O2 Rich/Lean vs. Airflow (bank1 AND bank2)? Some say to drop it to like 350 only at the airflow mode you are in at cruise speeds though. Word has it, this will get you several MPGs improvement. Doing this fools the PCM into pulling fuel due to the difference in the observed 02 crossing point and the referenced values in these tables. Stock table is 451 so anything numerically lower than that will lean out the mixture. You may want to play with the The General Airflow vs. Mode table since it determines which part of the B1S1 or B2S1 vs Airflow table you are on. Like I mentioned above, some have just set the R/L voltage to 375 across the board and have been fine however it would bother me that I was running "leaner" as I approached Pe mode or when the motor saw a heavier load. I personally haven't messed with these settings as getting a couple more MPGs isn't my top priority 
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Last edited by krambo; Nov 12, 2008 at 07:25 AM. Reason: spelling
Nov 12, 2008 | 07:30 AM
#35
Have you tried dropping your Rich/Lean Voltage of your 02 sensors for both Bank1 and Bank2 to something like 375mV (HPTuners > Engine > Fuel Control > OL & CL > O2 Rich/Lean vs. Airflow (bank1 AND bank2)? Some say to drop it to like 350 only at the airflow mode you are in at cruise speeds though. Word has it, this will get you several MPGs improvement. Doing this fools the PCM into pulling fuel due to the difference in the observed 02 crossing point and the referenced values in these tables. Stock table is 451 so anything numerically lower than that will lean out the mixture. You may want to play with the The General Airflow vs. Mode table since it determines which part of the B1S1 or B2S1 vs Airflow table you are on. Like I mentioned above, some have just set the R/L voltage to 375 across the board and have been fine however it would bother me that I was running "leaner" as I approached Pe mode or when the motor saw a heavier load. I personally haven't messed with these settings as getting a couple more MPGs isn't my top priority .
.I did a tune on an 05 GTO and I lowered the numbers in this table at cruise speeds and the guy picked up a solid 2-3 MPG.
Nov 12, 2008 | 10:34 AM
#36
From what i have been told the bucking is due to excessive timing in the load/rpm area, try lowering the timing in that area....
Last edited by BlackGMC; Nov 12, 2008 at 10:41 AM.
Nov 12, 2008 | 10:51 AM
#38
Take my advice with caution cause I am not the smartest tuner, like everything else each truck reacts differently....
Nov 12, 2008 | 10:54 AM
#39
Nov 15, 2008 | 07:45 AM
#40
This past week I made similar changes to this table in my tune on my truck and did not notice any drastic change in fuel trims, I always disable LTFTs in the tune and just tune off STFTs but did not see any large differences other than the 1-3% that I might get on different days due to temp change etc......
