Ok so ive been turbo for a short while now and ive noticed that i have been guzzling gas like no other. im talking like 4 times the amount i should be or used to. and when i drive at a steady throttle, especially low rpm my stutters pretty bad like its about to stall on me. this is not the case under boost. that leads me to believe that i am flooding the engine with fuel causing this problem. now my guess is that it could be the walboro 255 pump i have installed or its my fmu. which do you gusy think is more likely? with the fuel pump does it always pump more fuel or only when it is needed? i was under the impression it was just when needed. and with my fmu it could be faulty but im not sure. thanks for any help i recieve here.

what are you using to control your fuel? FMU, SFMU, SAFC II? Did you up your injectors or just your fuel pump?

i have a fuel pump and vortech 12:1 fmu
i have 450cc injectors but havnt installed them mdue to the fact that its too much trouble to rig a resistor pack so im looking for 440's.

the 12:1 fmu is known to run pig rich . also its not adjustable so you coulnt use the bigger injectors anyway . get rid of the fmu and get a sfmu .

If you don't already have one, you might want to install a mechanical fuel pressure gauge (~$25) near your FMU. It's pretty clear you're idling and/or running rich, or you got a fuel leak somewhere, but at least you'll see real numbers. Even with a 255 lpr pump I odn't think that alone would make it that rich. Like the others have mentioned, w/o an adjustable fpr, you're kinda limited. Also, did you remove the stock fpr?

yea i have a guage that intend on installing when i have time. and no i have not removed the stock fpr, i just put the fmu inline with it.

Originally posted by 98dsmNT
yea i have a guage that intend on installing when i have time. and no i have not removed the stock fpr, i just put the fmu inline with it.

That is probably your problem right there.

I 'thought' you were supposed to remove the Stock FPR when using a FMU.

I could be wrong, so someone correct me if I am, but I always thought the stocker was to be removed when changing.

No, if he only has a standand, Not a Adjustable FMU, then i think he has to keep the factory one in to keep the idle pressure correct. But i believe the 255 can over run the factory FPR and cause it to run rich!

Running the 255 Wally with the 12:1 FMU can definitely mess up the stock FPR. They dont seem to like 100+PSI lol. IF your stock FPR is faulty, it sure would explain the rich condition pre-boost. Do as they mentioned and check your fuel pressure. If there is an Autozone or comparable parts store that rents tools out for free with a deposit, get yourself a fuel pressure tester and see whats going on. You could always install the gauge you already have lol.

This post has the most bad info i have seen in the past 2-3 years.

Danny, THe stock FPR is fine with the walbro 255. You may have hooked up the FMU wrong or the FMU is bad. Staying out of boost the car should get normal gas mileage.

From the factory regulator the return line goes to the FMU fitting on the side of the FMU. The bottom fitting of the FMU goes to the return fitting on the tank. A vac line DIRECT from the manifold (No T's) will go to the top fitting on the FMU.

Check things out and get back to us.

Terry

Originally posted by Star Turbo Talon
This post has the most bad info i have seen in the past 2-3 years.

Man, I had just done mine yesterday and when I saw this thread I thought "Holy crap, I never knew all that was true, weird." Haha.

haha ok i was really confused there for a bit. i have the fmu hooked up right but i have the vacuum t'd not a direct line...could that be the problem? whats throwing me is that it ran fine a while ago until i drove into a ditch(dont ask) now its having fuel issues...im thinking it mite actually be a leak somewhere!

Originally posted by fly1
...did you remove the stock fpr?

Sorry! I meant the Shrader check valve on the fuel rail -- at least that's what was recommended when I had my fuel system put in a while back.

Or, if the fuel return line is kinked, that could also contribute to higher fuel pressure.

The Vac line issue would cause you to have issues in boost, not so much here. Change it anyway.

If this all showed up after you went in a ditch then get under your car and look for damage.

Terry

Originally posted by Star Turbo Talon
If this all showed up after you went in a ditch then get under your car and look for damage. Terry

What he said /\

My guess is you damaged the fuel tank, or possibly just a line. Either way, if it was fine before, and then you ran into a ditch, and now its messed up, chances are you messed something up by running into the ditch. Easy thing to do would just be to let your car idle on a dry driveway or something. Give it some gas, drive out of the way, and look for gas. But you should get under your car and check anyways.