Positive fuel trims affect WOT. Yes?
09-05-2010, 10:43 PM
#1
Racer
Thread Starter
Positive fuel trims affect WOT. Yes?
Commanded WOT AFR: 12:5
LTFT: +8 ~ +9
New WOT AFR: 11:5
Is this correct?
LTFT: +8 ~ +9
New WOT AFR: 11:5
Is this correct?
Last edited by SVT_Z06; 09-05-2010 at 10:45 PM.
09-05-2010, 10:57 PM
#2
Racer
Thread Starter
Also, does adjusting the injector slope too much screw everything up? My tuner says it puts additional load on the engine which slows things down. I currently have to adjust my injector slope -16 to -18 to keep trims around 0 to -2.
I have an '04 Z06 with just a Vararam intake and Halltech honeycomb MAF screen. No leaks. I've checked all vacuum hoses and used propane during my search for vaccum leaks.
I'm wondering if it's because I'm at sea level.....hmmmmm....
and I'm using a Diablosport Predator...custom diablew tune.
I have an '04 Z06 with just a Vararam intake and Halltech honeycomb MAF screen. No leaks. I've checked all vacuum hoses and used propane during my search for vaccum leaks.
I'm wondering if it's because I'm at sea level.....hmmmmm....
and I'm using a Diablosport Predator...custom diablew tune.
Last edited by SVT_Z06; 09-05-2010 at 11:12 PM.
09-06-2010, 08:52 AM
#3
Supporting Vendor
yeah man... like I said.. when fuel trims are positive, that extra fueling gets added on top of the wot/pe fueling table... I have already leaned out that table some in order to compensate for it, so your WOT is fine at this point...
BUT, with your trims being THAT far off, you should really get on a dyno and get your MAF/VE tables rescaled... not something that can/should be done via an email tune...
and no, it's not because you're at sea level... heh...
BUT, with your trims being THAT far off, you should really get on a dyno and get your MAF/VE tables rescaled... not something that can/should be done via an email tune...
and no, it's not because you're at sea level... heh...
Last edited by 06MonteSS; 09-06-2010 at 01:28 PM.
09-06-2010, 09:18 AM
#4
Racer
Thread Starter
yeah man... like I said.. when fuel trims are positive, that extra fueling gets added on top of the wot/pe fueling table... I have already leaned out that table some in order to compensate for it, so your WOT is fine at this point...
BUT, with your trims being THAT far off, you should really get on a dyno and get your MAF/VE tables rescaled... not something that can/should be done via an email tune...
and no, it's not because you're at sea level... heh...
BUT, with your trims being THAT far off, you should really get on a dyno and get your MAF/VE tables rescaled... not something that can/should be done via an email tune...
and no, it's not because you're at sea level... heh...
09-06-2010, 01:27 PM
#5
Supporting Vendor
09-06-2010, 02:38 PM
#6
Le Mans Master
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St. Jude Donor '13-'14-'15
Positive fuel trims at WOT are a result of a positive trim NOT at WOT but at the point JUST BEFORE going to WOT---Example --if you nail it at 3000 RPMS and then it goes into PE--whatever the + fuel trim is there will be added to your WOT fueling as well--( as a saftey factor) A negative fuel trim will always lock on "0" at WOT and will never subtract fuel at WOT thats why its important to get all your PT fuel trims at "0" or slightly negative
Every tuner tunes differently---I have had the best results with making small corrections ( less than 10%) by using the MAF table--and not the IFR table---When tuning with the MAF table-- you only need to make corrections in the PT areas---usually its around 6500HZ up to around 7500 HZ -- you don't want to make corrections in the HZ range where it's above that or it will screw up your AFR- ( make it richer)-Pin pointing where the + trims are at PT will eliminate the + trim at WOT as well---
Every tuner tunes differently---I have had the best results with making small corrections ( less than 10%) by using the MAF table--and not the IFR table---When tuning with the MAF table-- you only need to make corrections in the PT areas---usually its around 6500HZ up to around 7500 HZ -- you don't want to make corrections in the HZ range where it's above that or it will screw up your AFR- ( make it richer)-Pin pointing where the + trims are at PT will eliminate the + trim at WOT as well---
09-06-2010, 02:48 PM
#7
Racer
Thread Starter
Understood.
Looks like I should of did a little more research and went with the HP Tuning software or EFI live instead of the diablosport. I have the diablosport predator now with a custome tune from Lew and now, I have to fork out even more dough to get the MAF scaled properly. CRAP!
Looks like I should of did a little more research and went with the HP Tuning software or EFI live instead of the diablosport. I have the diablosport predator now with a custome tune from Lew and now, I have to fork out even more dough to get the MAF scaled properly. CRAP!
09-06-2010, 08:19 PM
#8
Turn off your LTFTs and verify that it is indeed adding that positive trim at wot and run open loop. Sometimes data logging will show positive fuel trims at wot that arent really there. Most likely you have a incorrectly scaled MAF/VE table.
09-07-2010, 10:11 AM
#9
Supporting Vendor
Understood.
Looks like I should of did a little more research and went with the HP Tuning software or EFI live instead of the diablosport. I have the diablosport predator now with a custome tune from Lew and now, I have to fork out even more dough to get the MAF scaled properly. CRAP!
Looks like I should of did a little more research and went with the HP Tuning software or EFI live instead of the diablosport. I have the diablosport predator now with a custome tune from Lew and now, I have to fork out even more dough to get the MAF scaled properly. CRAP!
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06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS LS3, short-throw shifter, NPP perf. exhaust, BMR strut-tower brace, Cold Air Inductions cold air intake, catch-can, ported/polished TB, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
09-07-2010, 11:39 AM
#10
Le Mans Master
You should not have fuel trims at WOT. If the afr error is off adjust the VE table accordingly and leave the PE set to what you want it to be.
Last edited by Slow Z06; 09-07-2010 at 11:42 AM.
09-11-2010, 09:59 PM
#12
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positive LTFTs carry over to PE, negative LTFTs do not. STFTs do not.
09-13-2010, 09:16 AM
#15
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09-13-2010, 08:36 PM
#17
Melting Slicks
Sure it will, now the commanded PE is as you have instructed.
Positive LTFT will "not" be added & never shall the modify your calibration again.
Mine have been turned off for well over a year.
Positive LTFT will "not" be added & never shall the modify your calibration again.
Mine have been turned off for well over a year.
09-13-2010, 09:27 PM
#18
Safety Car
09-14-2010, 09:30 PM
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Need a wideband to tune the WOT area!. Set PE to .85 Lambda straight across the board and tune MAF/VE to equal commanded AFR; use AFR error %.
Can use the trims for Stoich (non-PE) tuning and recommend tuning MAF only (set High RPM disable to 400 and hysteresis to 100) first, then VE only by setting Maf Fail to 0 and DTC P0101, P0102 and P0103 to fail on first error.
If Trims are less than 10%, you can disable the LTFT and use the STFT only; much faster to collect good data. Also reset the trims before each scan/tune session.
Set filter on scanner to >14 (keep PE out of scan) if using trims. Drive in a calm manner trying to avoid large transitions and stay out of WOT........
But as above...invest in a wideband and tune your butt off
Ed M
PS -- I have my LTFT's disabled as well.
Can use the trims for Stoich (non-PE) tuning and recommend tuning MAF only (set High RPM disable to 400 and hysteresis to 100) first, then VE only by setting Maf Fail to 0 and DTC P0101, P0102 and P0103 to fail on first error.
If Trims are less than 10%, you can disable the LTFT and use the STFT only; much faster to collect good data. Also reset the trims before each scan/tune session.
Set filter on scanner to >14 (keep PE out of scan) if using trims. Drive in a calm manner trying to avoid large transitions and stay out of WOT........
But as above...invest in a wideband and tune your butt off
Ed M
PS -- I have my LTFT's disabled as well.
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Vette Doctors Performance aka The Vette Doctors
52 Elm Place, Amityville, NY 11701 info@thevettedoctors.com or http://www.thevettedoctors.com/
(631) 841-0779
Featuring EFI Live/HP Tuners Performance Tuning in-house or remotely and HP Tuner/EFI Live training by ERM Performance Tuning
www.ermperformancetuning.com
Last edited by Ed@TheVetteDoctors; 09-14-2010 at 09:34 PM.