I just installed my drag kit on my LS. I noticed that when I start to get boost, the air/fuel guage goes all the way Lean, then picks back up and goes Rich. So it's kind of like :

Go into boost, hesitation ( my body is almost thrown forward ) for a second or two,
then acceleration.

What could cause this? The FPR doesn't look like it's adjustable, so I don't know what to do? Any help is appreciated.

 

bump

 

its not adjustable. do you have a fuel pump? could be not enough pressure for the FMU to work properly.

 

well the fmu works in conjunction with ur vacume lines.... you might want to check your vacume source.

 

HEY i have that Same problem.. i dont know what it is .. i dont have a aftermarket pump .. but my stock pump will hold 80 on the static regulator.. if i want it to ... im running the statis psi at 36 and on 6psi of boost ... timing is retarded.. and runs fine when i just rip it

 

Listen people if you think you can boost with nothing but a FMU and a stock fuel pump just drive your car off a cliff now and save yourself the trouble of getting it towed.....

With and FMU setup you ABSOLUTLY NEED AN INLINE FUEL PUMP..... so either don't boost till you get one, get a better fuel system (afc hack, standalone) or keep boosting and blow your stuff up.

Sometimes you gotta be harsh or else they won't get the point Just don't wanna see another blown motor that could have been avoided with just a little knowledge

 

Oh and honda-cutter get some allen keys, and take off the TOP cover of your FMU you may be running a smaller then 12:1 disc which wouldn't bee good, you can tell because when you take the cover off if theres a silver disk that takes up ALL the space allowed for it then its 12:1, if its smaller well then its a 10 or 8 or 6 depending on how small...

I had this problem and one day took the fmu cover off and sunofabitch I had a 10:1 disc in there, which explains why I was running lean and showing it...

 

well, it's the FPR that I got with the Drag kit, and I have a walbro HP 255 pump. I get enough fuel, it just takes a second for it to come in. But I could blow my motor in that second. That's why I'm worried, I'm trying different vaccum combinations so, I'll see what happens.

 

listen man... even the high pressure walbro intank pump is NOT ENOUGH to create over 100psi of fuel pressure a fmu setup demands, it at best makes 100psi of fuel pressure, at 7psi you need 125+psi of fuel pressure, and your NOT making that right now and you are running dangerously lean up top, so I suggest you get an inline, or go with the afc hack, because right now you are playing with fire.