LTFT Question
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TECH Apprentice
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Joined: Dec 2008
Posts: 363
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From: Racine, Wisconsin
LTFT Question I got my HPTuners Pro today. I have a question about LTFT on my wifes 05 A4 GTO with a TVS2300.
My LM-1 shows 14.4-14.8 at cruise, and plenty rich (11.8) over 3/4 throttle. So I am not really worried about burning up.
Here is a 2 minute log of the car idling, with a few throttle blips. At 1:30 I reset the fuel trims, the LTFT on both banks quickly rose back up to 24%.
Vacuum leak was my suspicion, but it seems like it would have to be pretty bad for the code to come on in less than 30 seconds, and I can't hear any leaks. MAF problem?
My LM-1 shows 14.4-14.8 at cruise, and plenty rich (11.8) over 3/4 throttle. So I am not really worried about burning up.
Here is a 2 minute log of the car idling, with a few throttle blips. At 1:30 I reset the fuel trims, the LTFT on both banks quickly rose back up to 24%.
Vacuum leak was my suspicion, but it seems like it would have to be pretty bad for the code to come on in less than 30 seconds, and I can't hear any leaks. MAF problem?
Thread Starter
TECH Apprentice
iTrader: (2)
Joined: Dec 2008
Posts: 363
Likes: 2
From: Racine, Wisconsin
Thread Starter
TECH Apprentice
iTrader: (2)
Joined: Dec 2008
Posts: 363
Likes: 2
From: Racine, Wisconsin
Sorry, the HPT file is 1.4 mb, this site has a 1.24 limit. Here is what the car has now.
I would attach the hpt file, but it is over the limit.
The LS9 injectors are about 56#/hr @ 4 bar. The tune I started with actually had a higher flow rate, something like 58#...
After changing that, I forced MAF only. I found the maf was off by between 22 & 35%.
I cleaned the MAF, ran it again, no change. If I had a vac leak, I would have expected the worst MAF error at low rpm, that was not the case, the worst maf error was around 2800 rpm.
After about 5 iterations, the LTFT error is under 1%.
Also, the PE table didn't make sense to me it didn't ramp the afr, it just had a few big steps, and really didn't give adequate fueling, I currently have about 11.9-12.0 AFR from 2000 rpm & up, but may go slightly richer.
I haven't done anything with the spark tables yet, but my logs haven't shown any KR so I don't think I am in danger of blowing its guts out with this setup.
I have only had HPtuners for about 1 week, so I have plenty left to learn.
Sorry I can't post the hpt file.
I would attach the hpt file, but it is over the limit.
The LS9 injectors are about 56#/hr @ 4 bar. The tune I started with actually had a higher flow rate, something like 58#...
After changing that, I forced MAF only. I found the maf was off by between 22 & 35%.
I cleaned the MAF, ran it again, no change. If I had a vac leak, I would have expected the worst MAF error at low rpm, that was not the case, the worst maf error was around 2800 rpm.
After about 5 iterations, the LTFT error is under 1%.
Also, the PE table didn't make sense to me it didn't ramp the afr, it just had a few big steps, and really didn't give adequate fueling, I currently have about 11.9-12.0 AFR from 2000 rpm & up, but may go slightly richer.
I haven't done anything with the spark tables yet, but my logs haven't shown any KR so I don't think I am in danger of blowing its guts out with this setup.
I have only had HPtuners for about 1 week, so I have plenty left to learn.
Sorry I can't post the hpt file.
I agree, as long as you entered the injector data correctly you should only need to tweak the maf to have the proper WOT fueling. If you changed the airbox and how the air enters the maf it will almost always be out of calibration.
You should only need to pull the injector data from a stock ZR1 tune and cut and paste it into yours.
You should only need to pull the injector data from a stock ZR1 tune and cut and paste it into yours.
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