Killer '01 SS

iTrader: (2)

A month ago I logged my LTRIMS and found that cells 4-16 were averaging about +6%. I wanted to get them down to about -1%, so I multiplied the entire MAF table by 107%. I logged my LTRIMS a day after the change, and again a month after the change, and on both occasions, cells 4-16 are averaging +0.3%. Not bad!

So here's my question... Cells 4-9, which represent most of my cruising and non-WOT driving, are consistently near zero, or generally slightly negative (although some small positive numbers pop up occasionally). BUT cells 12 and 13, which are the cells the car is in immediately BEFORE WOT, are consistently +5 to +7, commanding extra fuel just as the car goes into WOT. So with the current PE Mode table, the car is running richer than it should at WOT. (i.e. black smoke out the tailpipes... fine for James Bond, but a faux pas on the highway. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> )

Would you adjust the MAF table again, just to bring cells 12 & 13 closer to zero, even though that will put the other cells into the -5 to -7 range, OR would you leave the MAF table alone at this point, and just adjust the PE Mode table to eliminate the rich condition at WOT (counting on the extra fuel from the LTRIM adjustments of cells 12 & 13)?

(NOTE: I don't use nitrous, so the A/F ratio at WOT isn't CRITICAL (a little lean isn't going to break anything if I just lean out the PE Mode table), but I WOULD like the car to be tuned properly.)

TIA.

<small>[ March 27, 2003, 01:38 AM: Message edited by: Killer '01 SS ]</small>

Killer '01 SS

iTrader: (2)

You're in here reading this thread... Might as well give me your input. <img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" />

Doc99SShome

I would do some more scans and determine at what frequency you are at in the MAF table for fuel cells 12 and 13. Then, I would take the middle frequency and multiply it by 105%,, and the tapper off in both direction by 1/4%.

For example, if the middle frequency of fuel cells 12 & 13 is 7500Hz, then I would multiply that cell by 105.0%, multi the 7625Hz & 7375Hz by 104.75%, multi the 7750Hz & 7250Hz cells by 104.5%,, etc,, etc.

Check your work in the graphics mode and compare to your previous MAF table. Be sure to have a smooth curve. Upload the new program, and do some more scans after a 15 to 20 minute drive. You will have to visit fuel cells 12 and 13 for several minutes each for the re-learn process,, then take a new scan and compare to your previous scans from the old MAF table. You can work on just a portion of the MAF table if you are deligent about your process.
<img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Killer '01 SS

iTrader: (2)

Thankyouthankyouthankyou!!!

That's the information I was looking for... How to accurately change one portion of the MAF table.

I really appreciate it!

Killer '01 SS

iTrader: (2)

Will do. Thanks again!

Doc99SSx

The key to this method is to have a smooth transition,, that is the purpose of changing 0.25% each next cell in the MAF table. A more aggressive transition would be a delta of 0.5% each cell instead of 0.25%. Anyway, I think that you have the idea. BUT, be sure to check your work in the graphics mode in LS1Edit.