venom346

iTrader: (7)

Recently I spent good money on a custom dyno tune from a shop for my h/c/I corvette.

The other day just for the hell of it, I hooked my handheld diablo to the car as I drove and decided to monitor my driving conditions. I did notice that my LTFTs were in the -12 to -10 range. Should I trust his judgement and leave it be, or should I adjust the pe ratio myself and bring it up to the -2 to 0. Range? I remember seeing on diablo tuning that almost 0 is best, but the tuner used hp tuners so I assume that the diablo is not as accurate?

edcmat-l1

iTrader: (10)

The scanner function of your Pred should be fine as far as accuracy.

Adjusting the PE ratio won't change your closed loop fueling.

The FTs should be a bit closer, but if it's running OK, I don't know if I'd bother with it. If you're that concerned, how bout contacting your tuner and asking him about it, and see if he can't dial them in a bit closer.

Gabbiani

iTrader: (20)

Long tubes?

venom346

iTrader: (7)

Yea, long tubes, cam, ported heads and vararam intake..... the -12 ltfts were concerning me because I was wondering id I was just wasting fuel while commuting because I know my gas milage suffered since the tune. My tuners kind of an *** and I really want to avaoid going back there as a few other tweaks and code diabling I had to go over and do on my own.

I adjusted my injector slope to bring the ltfts more evenly....

ysb02

Go to someone else. I just spent ~5 hours the past two weeks tweaking the VE table in mine.

Have you swapped injectors from the stockers?

venom346

iTrader: (7)

Still stock injectors... 60lbders are still on the shelf

Ryne @ CMS

iTrader: (10)

being that the fuel trims are negative i wouldnt worry too much, although they arent suppose to be that high, i would just put a Wide band on it and verify you WOT AF is good and be done with it....

Ryne @ CMS

iTrader: (10)

you are not really wasting much fuel because the computer is pulling fuel to get the AF back to Stoich while cruising.... you may suffer a little bit of fuel economy when you first start the car and the car is in Open Loop, but even then it might not be too far off because the LTFT's are negative, so the computer memory is of a rich condition there for its already pulling a set amount of fuel even before it goes into closed loop

Mike454SS

iTrader: (4)

If it were my car, I'd re-tune it...you're probably not hurting anything, but I like seeing fuel trims on my own car within +/- 2-3% all the time.

venom346

iTrader: (7)

Exactly... for the money paid. It would be expected to be close to

JDMC5

iTrader: (3)

I would expect it to be closer myself. If your injectors are stock then leave them alone. You should dial the trims in with the maf or VE table depending on if you run an SD or MAF tune.