06cobalt racer

iTrader: (11)

I was checking my ltft's today and they are -20.3 when accelerating. I know that the closer to zero the better. What needs adjusted to be adjusted? Right now i have a canned tune from ottp, I will be getting a custom tune soon. But what in the tune would need changed?

Mods:
Ottp stage 2
eBay cai
Full exhaust

thedude411

iTrader: (1)

Hmm subd

BLAZIN07SS

iTrader: (7)

the maf needs to be scaled

Sharkey

iTrader: (1)

a positive value means the pcm is adding fuel, a negative value means its removing fuel. the value is a percentage, so your pcm is removing 20.3% from what that cell in the fuel table is tuned for. a number of things can be causing this, a boost leak, clogged injectors, high fuel pressure, your intake (intakes do funny things to drop in maf sensors) or the tune is just way to rich for your car.

firepinch

Could wrong spark plugs gap do this too? And what about bad spark plugs? I'm confused too as to why I'm getting LTFT like the OP said... But it seems that my LTFT are screwed after a rainy day. I'm gonna test out today, no rain since yesterday and its sunny.

Thanks a lot Sharky for your GREAT explanation of what LTFT are... I was looking for that kind of answer!

Update: When I said wrong spark plug gap, I meant for example your spark plug gap is 0.036 instead of 0.032.

I don't think personally this could make a difference for the LTFT during a part throttle acceleration... you know... when you think about it, it makes sense!

yellowsupercharged06

iTrader: (3)

bringing this topic back , i have the same issue as the OP did .. any one got a solution ?

user 72239

iTrader: (4)

When my fuel trims were that negative i had a massive boost leak. However this is on an LNF not an LSJ.

umrdyldo

iTrader: (1)

Wouldn't the leak have to be post MAF?

If so check all fitting near the throttle body. Do you hear anything crazy?

20% is major.

QuickSilver_SS

-20% is alot. And I thought my -9.6% was bad. Of course mine is also an lnf. But either way , that is alot.

yellowsupercharged06

iTrader: (3)

Im an LSJ so im not too sure how different it would be.

I have a mechanical boost gauge and it seems to be reading boost like it should be, -20 ish vac. and full boost i hit about 16lbs .

Its only at cruising where i see the -20.3 LTFT, my AFR is normal under WOT and cruise .... maybe an injector is sticking open to cause it ?