Please explain "Fuel Trim Cell"
Please explain "Fuel Trim Cell" Could someone please explain in detail or provide a link about what "Fuel Trim Cell" means and why?
Always heard people mentioning it, but never knew what it meant.
Thanks in advance.
Bill
Always heard people mentioning it, but never knew what it meant.
Thanks in advance.
Bill
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From: Whitby Ont Canada
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Originally Posted by Billiumss
Could someone please explain in detail or provide a link about what "Fuel Trim Cell" means and why?
Always heard people mentioning it, but never knew what it meant.
Thanks in advance.
Bill
Always heard people mentioning it, but never knew what it meant.
Thanks in advance.
Bill
Here's an excellent link on EFILive to FTCs and their arrangement. ->FTCs Matrix
Here's a good pic ->
For example with this VE table ( calibrations differ some) at and above MAP= 76 kPa, and above 2000 RPM, the PCM is referencing LTFT #15.
Hope this helps some
Last edited by Bink; Apr 29, 2004 at 10:11 PM.
It looks like the fbodies have only 3 rpm ranges (4 technically).. below 2500, between 2500 and 6502, between 6502 and 6503, and above 6503. I wonder if anyone has changed these to make better use of the pcm's ltft tuning.. I would think a below 1200, between 1200 and 2000, between 2000, and 2400, then above 2400 would give much better part throttle tuning, since the pcm has finer control of the trims. Has onyone tried this?
Originally Posted by FDLS6
It looks like the fbodies have only 3 rpm ranges (4 technically).. below 2500, between 2500 and 6502, between 6502 and 6503, and above 6503. I wonder if anyone has changed these to make better use of the pcm's ltft tuning.. I would think a below 1200, between 1200 and 2000, between 2000, and 2400, then above 2400 would give much better part throttle tuning, since the pcm has finer control of the trims. Has onyone tried this?
The Z06 table is exactly what is represented in Bink's graphic in terms of cell distribution. No clue why GM set the F-bods up like they did...basically crippled their ability to manage fuel trims.
Cool.. that's my plan too. I may not use the exact same rpms' as the z06, but definitely like the idea of using more cells.. thanks for the feedback.
Originally Posted by crainholio
I did. Copied the boundary table from an '01 Z06 file I snagged from ls1edit.com archive, and I'm getting more cells in use during driving.
The Z06 table is exactly what is represented in Bink's graphic in terms of cell distribution. No clue why GM set the F-bods up like they did...basically crippled their ability to manage fuel trims.
The Z06 table is exactly what is represented in Bink's graphic in terms of cell distribution. No clue why GM set the F-bods up like they did...basically crippled their ability to manage fuel trims.
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so wait.
Can you post your FTC cell settings, and explain the repercussions one might have with PE fueling.
Honestly my car sees about 0-50% TPS on streets and highways (too many tickets), then only at the track does it get its 100% TPS all the time.
would i gain much given my city style driving, with a little freeway (cruising) and only track (PE mode)?
Can you post your FTC cell settings, and explain the repercussions one might have with PE fueling.
Honestly my car sees about 0-50% TPS on streets and highways (too many tickets), then only at the track does it get its 100% TPS all the time.
would i gain much given my city style driving, with a little freeway (cruising) and only track (PE mode)?
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Originally Posted by samz28
so wait.
Can you post your FTC cell settings, and explain the repercussions one might have with PE fueling.
Honestly my car sees about 0-50% TPS on streets and highways (too many tickets), then only at the track does it get its 100% TPS all the time.
would i gain much given my city style driving, with a little freeway (cruising) and only track (PE mode)?
Can you post your FTC cell settings, and explain the repercussions one might have with PE fueling.
Honestly my car sees about 0-50% TPS on streets and highways (too many tickets), then only at the track does it get its 100% TPS all the time.
would i gain much given my city style driving, with a little freeway (cruising) and only track (PE mode)?
RPM MAP*10
900 370
1400 570
2200 770
How much you gain depends on how accurate your VE table is for your engine, or how much your driving conditions vary, eg. if they switch to blended/oxygenated gas in the Fall where you live. Get some AutoTap or EFILive data while you're driving, see how much the LTFT values vary across a given FT Cell.
Chances are you'll see the same cell being used quite a bit, and with wildly varying LTFTs...unless your VE table happens to be nailed down close to perfect.
