[Casper98GT]

Yeah, checked them all. They are all very easy to get to in my car. They are brandnew 24lb FRPP injectors i got from work. Checked wiring harness none of them are grounding out. All plugs look great and none are fouled.

[nolife]

Originally Posted by Casper98GT I filled up and drove it for ONE day. Im at half tank with 60 miles on it. I put a fuel pressure fitting on the fuel rails and turn the key on....thats it. JUST ON and the pressure shoots up to 40-45psi and then shoots down to 10psi just as fast as it shot up to 40-45. Then slowly to zero. Im stumped..... SOMEONE????

Do you still have accurate adjustability with the regulator? Can you easily change pressure 5-10 or so pounds in each direction?

The diaphram in the FPR may have a hole in it, is there any fuel coming out of the vacuum port on the FPR when the car is running? Does the intake piping smell like fuel or is there fuel in the oil? If you are really using that much fuel, it has to be going somewhere. I would suggest getting some A/F readings to at least see if it is burning it. That issue would fit both problems you are having, excessive use of fuel and rapidly dropping fuel pressure. A stuck or leaking injector or faulty wiring to an injector would do almost the same. Looking at your plugs might give a clue for that.

You could also have a combination of issues or a pinched return line or a really weak fuel pump. The pinched return line would increase fuel pressure causing excessive fuel use and make the FPR unable to maintain pressure but it should show the high pressure on the FP gauge. A weak fuel pump would cause erratic fuel pressure but should not cause excessive usage.

EDIT: After going over the thread again, it looks like you already checked just about everything I suggested. oh well

[95opal]

Originally Posted by Casper98GT Hey buddy. whats up. The engine running i set it at 42psi. It holds steady with no problems. Runs perfect, has alot of power, no hesistation. Im 100% positive its not the pump. Pinched off the return line and it still goes out. Im just not sure where its going then. unless i have a crack in the intake somewhere, or the intake line causing it not to hold vaccum. Im out on vacation this entire week so i have no access to tools. So even if it were the regulator. Any thoughts as to the horrible fuel milage?

So you arent having any driveability issues? The only problem is very poor gas mileage? I know you just installed a new pump so I will ask, How was the filler neck gromet? Did you install a new one? I ask cause sometimes they will get a tear in them and fuel will leak out. Just something else to consider.

[gotn20]

how do you replace that cause mines torn.

[Casper98GT]

So you arent having any driveability issues? The only problem is very poor gas mileage? I know you just installed a new pump so I will ask, How was the filler neck gromet? Did you install a new one? I ask cause sometimes they will get a tear in them and fuel will leak out. Just something else to consider.

Just went outside and played with it alittle. Checked fuel pressure and dropped it a few psi. But yeah...no driveability problems. starts almost immediatly, no hesisatation, pulls strong through the rpms. Fuel pressure stays steady with it on, can adjust it without any problems.

I installed a new 255 Walbro, all new clips, fuel filter, fuel pump assembly o-ring, new lock ring, and new filler neck seal. Sits in garage and no fuel smell. No leaks of any kind. Just went out and drove it 20 more miles and its now a line below the half.

[Casper98GT]

how do you replace that cause mines torn.

Filler neck seal: just disconnect all elect. connections. Then drop the tank straps ( make sure you have a jack under it, lowest amount of fuel is the best, so its light ) remove the bolt holding on the hold down, drop the tank and remove the filler neck. Replace the seal and put back together.

[gotn20]

yeah i just put in a 255 a couple days ago but i didn't see that the seal could come out. mine is torn.

[Casper98GT]

yup, has like 2 little ears on it. Just pull it out of there and put in the new one. Make sure you lube it. Goes in easier

[SALIV8]

are you sure you're sending unit is accurate?

I'm pretty sure the floats sometimes get gas in them, and then they're done.

[ujslost]

Originally Posted by gotn20 yeah i just put in a 255 a couple days ago but i didn't see that the seal could come out. mine is torn.

I keep one of those seals on hand, cause it seems if your seal is a few years old its nearly guaranteed to have a crack in it after you pull the tank.
latemodelrestoration.com sells them for like 20 bucks.