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Well I am trying to figure out how to get my ltft straighted out. I am not sure how to adjust it with my maf table. Well I do but i don't know how to get the percentage to adjust it. I get a -6 to -7 on the ltft. I just want to pull it in a little closer. Also for some odd reason i get a 1 to 4 degress knock when I push the pedel to acclerate then it goes away. Here is a copy of the tune, log, and gauge configuration. Thanks
The knock you are getting could be rich knock or coud be somethine else. To get your LTFT back into line you if they are negative 7 you would mulitply all the values in the MAF calibration table by 0.94. That should get you within -1 to 0 but you have to log and recheck.Quote:
Originally Posted by laser_racer
sounds good to me but the question i really would like have answered is how do you get the 0.94. so if i needed to fix a friends car and its -8 or 9 instead of -7?
Negative 7 means your car is substracting 7% fuel to get it to 14.7AFR. Under Airflow, MAF Calibration; you would select the MAF Freq. at which it is -7 enter .93 (or .94 to not overshoot) and hit the X, this will decrease it by 7%.
What I do under the VCM scanner histogram is edit it and add this ([PID.6310] < 16) & ([PID.4] < 60) and change the X header to MAF Airflow vs. Output Freq. What this does is tell it to ignore and fuel trim cells above 15 which is idle, etc and use only loads under 60%. This will also put the histogram into a single line which looks like the MAF Calibration above. I done this on mine and my LTFT are usually within +-1%. I usually do my logging in the AM when ambient temperatures are fairly constant and try to do as much steady state driving at various RPMs as possible.
what i want to know out of all that is how do you figure out -7 equals .93 or .94?
The LTFT is a percentage that the PCM is either adding or substracting from your fuel flow to get 14.7 AFR, so to decrease it by 7% you would multiply it by .93 or to increase it by 7% it would be 1.07. A multiplier of 1.00 would be no change.
You can't divide in HP Tuners, so you multiply by the inverse.
1 divided by 1.07 (for the -7% you are off) = 0.9345 Multply the entire table.
If your buddy is off -9%, then his would be 1/1.09 = 0.9174
Conversely if you were at +7%, you would multiply by 1.07 across the board.
Hope that helps.
Thank you very much that is exatly what I was looking for.Quote:
Originally Posted by Iam Broke
Now to the next topic i go.
O ya does anyone know how i can get rid of this knock when just pushing the gas pedal to start accerlerating???
Like previously said, it could be from being too rich. Another thing you could do it modify your tip in... Are you still running stock timing? What is your PE lambda set at?Quote:
Originally Posted by laser_racer
I am just trying to figure out how i can keep it from running rich at that point then. not really sure what my pe lambda is set at. i put my tune up there so someone might be able to point it out for me. the timing has been changed some. i might just put my stage 2 timing back on and start over on adjusting the timing.
Whats mods do you have on your car?
lets see got k&n intake, ported throttle body, full race port on head intake to the exhaust, cti header back 3" exhaust, 2.85 pulley, 42lb injectors, and diamond pistons stock compression. have a 2.7 and 60lb injectors to install still but waiting till I learn little more.
PM sent...
I don't claim to be an expert all I know is what worked for me, and I would only multiply the entire table by an amount if most of the cells were off by that amount, then I would use my method to tweak it, then smooth the table.
If the knocking is only ocurring when you first step on the gas, I wonder if it just might be a transient thing. In my case it was due to low octane premium fuel; I mixed a little racing fuel with my gas and never saw any knock retard on a dyno or otherwise.
ya i am going to do some maf tuning on the car and see if it helps. Thanks 04redline!!! also i am going to switch to e-85 after i get everything figured out.