SD vs. MAF car feels much better, but why?
03-13-2007, 06:29 PM
#21
Not so easy with AutoTap (commanded AFR... WB output...).
I usually log for LTFT, STFT, fuel trim cell and MAF frequency.
I add LTFT and STFT and average the banks, then put the values in a pivot table (Excel) and see what correction I have to do for each specific frequency in %.
I then have to smooth the curve by hand.
I only use cells 0-19.
For PE I was thinking to watch the AFR and compare it to the commended enrichment in the PE table. But I don't know if this method is really precise. AutoTap has no connectors for external signals
and I have to look at the display of the WB (not so easy... at WOT on the highway hoping no cops are sitting around!)
I usually log for LTFT, STFT, fuel trim cell and MAF frequency.
I add LTFT and STFT and average the banks, then put the values in a pivot table (Excel) and see what correction I have to do for each specific frequency in %.
I then have to smooth the curve by hand.
I only use cells 0-19.
For PE I was thinking to watch the AFR and compare it to the commended enrichment in the PE table. But I don't know if this method is really precise. AutoTap has no connectors for external signals
and I have to look at the display of the WB (not so easy... at WOT on the highway hoping no cops are sitting around!) 
03-13-2007, 07:41 PM
#22
Originally Posted by tici
For PE I was thinking to watch the AFR and compare it to the commended enrichment in the PE table. But I don't know if this method is really precise. AutoTap has no connectors for external signals
and I have to look at the display of the WB (not so easy... at WOT on the highway hoping no cops are sitting around!)
03-13-2007, 07:44 PM
#23
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Yeah, that sux. You need to try getting the WBO2 logged in relation to the RPM's or the MAF Hz in order to tune it or else you'll have to make general corrections to the MAF and then tweak with the PE table. A dyno might be a better place to do this...
03-14-2007, 07:09 PM
#24
Originally Posted by patSS/00
You can connect the WB output in place of the EGR output (to the PCM), then monitor that in autotap. I forget which wire it is, but there's a thread from way back that shows the wiring diagram.
The MAF is back and the car feels as good as in SD
It looks like it was necessary to adjust the VE table!
LTFT's are now really close to zero and STFT fluctuate only by +/- 4% (with the stock VE table they used to jump +/- 10-12%).
