twinturbo496

iTrader: (2)

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?

JDMC5

iTrader: (3)

Doesn't look like a vacuum leak. What are your mods and is this a stock tune? Have you checked fuel pressure? Maybe a bad fuel pump or clogged filter.

JDMC5

iTrader: (3)

well, after reading your post over on hptuners forum I'm convinced you entered the injector data wrong.

twinturbo496

iTrader: (2)

It was slightly incorrect, however that wasn't the only problem. The car runs pretty good now, but I changed way more than I was expecting.

JDMC5

iTrader: (3)

do you mind me asking what else was wrong?

twinturbo496

iTrader: (2)

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.

JDMC5

iTrader: (3)

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.

twinturbo496

iTrader: (2)

I haven't looked at a ZR1 tune, but as I understand it, they don't use constant fuel pressure...