negative fuel trim pegged? kr help

[nickburgundy]

ok seems I have an issue. Did my gen v n* a while ago and all seems fine. I have noticed quite a bit of kr lately, even at really low boost. The other thing I noticed is my ltft are pegged negative about 12.5 or so. I have checked my vac lines, and did find one. That got me from -14.5 to the current -12.5 ltft. I have sprayed starting fluid around with no luck there. intense pcm w/ evap delete genv n* lq4.

[00Beast]

Sounds like you have a fueling issue. How's your fuel pressure look?

[Mechanical Mike]

A negative fuel trim means its running rich. I find it strange that it sounds like you fixed a vacuum leak & the fuel trim went leaner. Are you sure the trims are negative?

I'd get a scan of the MAF sensor at idle & cruising at 60 mph.

[J Wikoff]

I'd find the O2 sensor as a suspect, too.

And... your sig pic is too large and the software is blocking it. 700 pixels wide by 200 tall is the max.

[nickburgundy]

ok I have not checked fuel pressure as it is rich.
When I fixed the vac issue it went more towards lean but is still very rich.
I would assume the 02 itself should be fine as I replaced a few months ago with a denso
any chance my lq4 is bad? how to scan?
Anything said here I can and will check or do though.

[00Beast]

I wonder if it isn't the Intense PCM to be honest. Canned tunes cannot accurately reflect all of your mods....

[nickburgundy]

true it could be but john was aware of the mods and felt really confident, but would this affect the kr I am seeing? Also doesnt that seem really rich to you? as soon as the gas pedal is pressed the ltft goes into negative numbers

[nickburgundy]

ok checked the fuel pressure. It said 49 at the rail key on and held it for a minute, then I turned the car on and it went to about 45 ish, when I throttled up the fuel pressure went up over 50.

02 is 920 at wot

and still kr with the 3.8 genv n* headers intake

[00Beast]

How quickly is the O2 switching at idle? Is it very quickly (once a second) or slower (several seconds)?

[nickburgundy]

seems pretty quik, but I did notice it get stuck a few times, ie it was cycling and it would stop @ ex. 65 for a second and continue on, but it seems to be working good. Although my big issue is if the aeroforce says -14 plus or whatever is that rich? and if it is why kr?

[00Beast]

Yes, negative numbers means rich fueling for fuel trims. Why KR? Because knock is still occurring, for whatever reason.

Have you reset your fuel trims with the aeroforce? It's kind of a short-term fix, so don't expect it to be right, but obviously for some reason it's getting more fuel than your PCM wants to see, so it's trying to reduce it.

[nickburgundy]

yes i did reset ed

[00Beast]

Yeah, I don't know. Might be worth a shot to call Intense and see what they have to say...

[nickburgundy]

I did and he thought maybe it was the fuel pump or pressure. so i'll have to call him tomorrow with my new findings

[00Beast]

With negative KR though? Means your base tune has too much and the PCM has to remove fuel to hit 14.7:1.

How much fuel have you burned? I almost wonder if you didn't get an E85 fuel trim accidentally?

[nickburgundy]

well yesterday I believe i burned 5 galons in about 40 miles round trip. The thing is I felt like the tune was good for a while, because I really don't remember that kind of kr

[J Wikoff]

Lord. Pull your fuel rail out, with everything hooked up, fuel, injectors, wiring, and turn the key to on, but don't try to start it. Does fuel come out of any of the injectors?

[00Beast]

[nickburgundy]

ok what does this tell us? im a noooooooooob

[00Beast]

Whether or not you have a sticking injector...

Also, this is me being brutally honest, this is why it is vital to do your homework before you mod, instead of just finding parts and throwing them at your car. This is not just aimed at you, but at a lot of n00bs. Throwing parts at a car that has no plan is a car with a bunch of parts on it. A well planned project will work the way you want it to, and do what you want it to do, and everything will work while you're working on it. All of the mods I have done have been in this fashion, mostly, and my car has never had "major" compatibility issues that I've seen a LOT both here and with the GP guys...