Wideband goes to lean at 5500rpms (using SAFC2)

[BigRand]

Okay, it doesn't help that I my car isn't runnig right now any more, but I wanted to ask about a problem I had earlier when it did run, so that when I get my new tranny, I can fix the problem right away.

Okay, so I'll be running the following setup

STAR STAGE 2 turbo kit @5psi.
Vortech 12:1 FMU
stock injectors
190 fuel pump
SAFC2.


Okay so when I'm driving and I look at my wideband everything is perfect. I go to hit WOT and the wideband goes to rich side a lttle bit but its expected. But as soon as I hit 5500rpms the wide band swings to rich then swings to lean. So I let off. I tried to add fuel to my SAFC, but then it threw a CEL saying I was dumping too much fuel.
FYI this is on my brand new built motor with the inernals found in my profile, and so I wasn't taking any chances on screwing this one up.

I was talking to a mechanic and he said it might have something to do with the fact that the vaccume line coming from the FMU in the back is so long, and or there might be some kind of rip or something in the line. OR something wrong with the FMU sending fuel fast enough?

Any thoughts?

 

[selmerguy]

do you have a fp gauge. if you do then when you hit boost you should see it move. i am using the 12:1 fmu and boosting about 7.5 psi. my idle fp is between 50 and 60 but when i hit full boost it pegs out.

how lean does it go? afr???
i am assuming you have some kind of logging setup to know that at 5500 rpm your afr is lean. so what does the rest of the fuel curve look like?

good luck man i hate fuel systems too.

 

[BigRand]

do you have a fp gauge. if you do then when you hit boost you should see it move. i am using the 12:1 fmu and boosting about 7.5 psi. my idle fp is between 50 and 60 but when i hit full boost it pegs out.

how lean does it go? afr???
i am assuming you have some kind of logging setup to know that at 5500 rpm your afr is lean. so what does the rest of the fuel curve look like?

good luck man i hate fuel systems too.

No, I don't have a logging set up yet (emange and e01 are going to be put in), but I just watch as I'm driving everytime I hit about 5500rpms my wide band goes all the way over to lean. (couldn't give you the exact airfuel # because I have the lambda display, but it goes as lean is it can get).

I don't have a fuel pressure gauge (not installed yet).

I am planning on running a fuel return line back to my tank, and using steel braided lines through out the fuel system. I just wanted to know what I can do for now because this whole emange set up keeps getting pushed back due to other problems that cost me money.

I do have a custom high volume fuel rail currently on as well, do you think that could be a problem?

I think it just has something to do with a vaccume or fuel fitting on the fmu, and when I get my car back I'll take a look at it, along with the hose for the vaccume line. Maybe if there is a slight hole or something in it, the fmu won't rasie the fuel high enough to keep up with the boost

 

[XMasta19]

Everywhere I've read talks bout the stock fuel rail being just fine...do you still have it laying around to throw back on there?

 

[BigRand]

the only reason I even got a custom fuel rail is so that I can easily run a fuel return line off the end off the end of the new rail, without fabricating the stock one so that if I did want to put it back on later I wouldn't have messed with it.

 

[selmerguy]

the only way to tell if your fmu is working is to have a fp gauge installed. if you have one install it and see. i installed mine on the stock rail but if you have a custom rail it should be even easier.

i dought that your custom fuel rail is the problem. when i didnt have a wideband or fp gauge i remember when my fmu vac line got a hole in it. my car felt really slow. if your car feels slower than it did it might be the problem. '

again good luck

 

[420aVOS]

what is your safc set at when you are at 5500 if you are at 100% DC on your injectors it might just be that you are running out of flow through the injectors or because your fuel rail is larger you might be out running your pump. you realy need a fuel psi gauge.