lose of low end after VE tuning
07-05-2010, 10:08 PM
#11
I noticed that when its commanding 21 degrees of timing at 2000rpm it's actually getting 13.5 so It's pulling timing somewhere. I can't see anything pulling timing other than maybe B1901 set at 300ftlbs but I thought that would only matter if he has Traction Control.
Perhaps we need more VE tuning?
Perhaps we need more VE tuning?
Few things here.
Are you looking at High Octane or Low Octane timing? You're running off of the low octane table with speed density.
The PID you're using for Cylinder Air Mass is not accurate, which is likely your "issue". Calc.cylair is derived from the MAF and is not used by the PCM for anything. You need to use GM.DYNCYLAIR to have an accurate cylinder air mass reference, regardless of whether you're running off of the MAF or speed density. I expect you'll find that the PCM "thinks" there is a lot more air entering the engine than actually is and is causing your spark reference to be a few cells to the right.
Don't be afraid to add more PIDs in. At the 16 channels you're logging, you're at 10 frames per second. You maintain 10 frames of data on up to 24 channels of data.
07-12-2010, 03:20 PM
#13
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I didnt even think to mention that before. That's one of those things that is just so automatic to me to copy the hi oct. table to the lo oct. table for tuning purposes when the maf is failed and I am tuning the ve, I had just assumed that you had done that.
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