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BMW 3-Series (E90 E92) Forum
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Fuel Trims and Timing Corrections
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11-20-2023, 11:14 PM | #1 |
Robot
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Fuel Trims and Timing Corrections
I recently flashed MHD Stage 1 91ACN a few days ago and got a chance to do some data logging:
https://datazap.me/u/lowrydr310/mhdv10s191acn-dtcdscoff Tune is for 91 but this was done on 94 octane (7 gallons of 91 and 3 gallons of 101) to rule out fuel quality issues. I don't understand the timing corrections. Before the start of the run there were timing corrections across all cylinders, then during the run there were no corrections. It looked perfect until I shifted into 4th then there were several corrections across multiple cylinders. I saw this same behavior on the stock tune. Anything to be concerned with? What causes this? Also, my fuel trims are off quite a bit between banks. Bank 1 short term and long term are much more negative; does that mean the DME is compensating for a rich condition? Bad upstream O2 sensor perhaps? Bad injectors spraying too much fuel? My Bank 1 injectors are index 1 original from 2007, but no signs of leaks. No misfires, plugs aren't wet or black, car starts up perfectly overnight with no smoke. Just these negative trims. Car has 160K miles, it was all stock when I bought it earlier this year. I replaced plugs and coils and got the intake valves walnut blasted right away, replaced PCV valve with the metal one from RB along with a new PCV flapper hose, and brand new boost solenoids. Also installed a new LPFP, regulator, and low side fuel pressure sensor. I think I need an upgraded intercooler. IATs went from 100 to 153 and ambient temps weren't even that hot. |
12-01-2023, 02:53 PM | #3 | |
Robot
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I actually had to repeat an earlier run immediately before the one posted above because I forgot to disable traction control. Here's the initial one with traction control left on: https://datazap.me/u/lowrydr310/mhdv10s191acn-tract |
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12-01-2023, 03:32 PM | #4 | |
First Lieutenant
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2007 E92 335i - MHD, Turbo Technics 19T's
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12-01-2023, 06:33 PM | #5 | |
Robot
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