I have been playing with my Datamaster software and logging a whole bunch and i have knock counts in the 3701 range. If you rev it up in neutral a couple times it will raise the knock count and eventually spark retard will go to 2 or 3 degrees. Is this normal? Also in closed loop my LTFTs are 111 but bounce around to 123 etc, under WOT they go to 128 and in open loop they are 128, fuel trim cell is 15-16 the whole time at and idle.

Car was tuned by ION at madz28
and has longtubes

Thanks for any help

 

Knock count is almost meaningless, as it resets once it reaches a certain value. Just look for areas of knock retard in your file instead.

At idle, you will be in cell 16.

If you are driving around and logging, you should not be in cell 15 all the time. If you are normally at 111 LTFT, then your MAF is reading more air than is actually entering the engine. The MAF tables can be adjusted to fix this. It's not really a problem in closed loop, but in open loop, you'll be running a little rich.

Dan

 

well thats the thing in open loop they read 128, thats normal right?

 

Yep, that's where they will always be because the PCM isn't adjusting for fuel yet based on the O2's feedback. 128 is ideal so that is the default in open loop. The LTFT can range from 100(PCM removing a lot of fuel) to 156(PCM adding a lot of fuel). The O2's aren't warmed up enough to provide accurate a/f readings in open loop.

Dan

 

With stock PCM programming, when the engine starts in open loop, it uses the stored long term corrections, but holds the short term corrections at 128 because there is no feedback from the O2 sensors. There are many other reasons the long terms will depart from 128, besides just the MAF calibration. Long term lower limit is 108 (-15%), upper long term limit is 160 (+25%). The long terms will only go to 128 at WOT (PE mode) when the long terms are pulling fuel out in closed loop. If the long terms are adding fuel in closed loop, the PCM will use the learned Cell 15 long term corrections. All of this can be changed by the programmer, if he chooses to.