WTF is going on??

[GLHNSLHT2]

no it's not setting off the knock sensor. I put the fuel pressure gauge on it and hooked a clear hose into a bucket to it. Pressed the purge button and let the fuel flow. Took a while but air bubbles started coming out. So I've got air pre-rail. But there's no leaks I can see outside the car. I can stick my ear up to the fuel filter and hear it gurgling as well as climbing into the back of the car and listening above where the fuel filter is.

I'm lost, what should I check? Thanks for your help guys! I really appreciate it! This is the only site I'm getting anything from.

[crazymadbastard]

gotta pull that pump out, I am not familiar with the older fuel system but my gues is that maybe the pump is twisted such a way that it can suck in air or maybe somewhere along the body of the pump housing you have a crack and suck in air there.
is this the setup? lots of plastic to crack

[jim34]

I agree pull the pump out, you can have good pressure but the volume will be severely reduced if theres a leak in the tank

[puppet]

OK ... random wild theory time.
Your static pressure is too high ... should be 55psi. I think you crushed the nipple on the FPR return loop.

The pump sits in a reservoir inside the tank. The return line goes back to the tank and empties inside the reservoir near the pump. Initially, either the air is returning to the tank from the FPR or it's going to the rail from the pump. After it's running the pump will supply air if the return line is a fault. So you don't know which is giving you grief.

Do you know how to power the pump without the engine running Jay? The ASD relay powers it. I'd disconnect the return line at the tank and run it to a bucket ... power the pump and check for air coming back. If so, I'd disconnect the fittings at the FPR return nipple ... connect a length of hose and repeat the test. If you're still getting air disconnect the fuel supply line at the tank and connect a length of hose to the pump itself. Run it in a bucket and check for air.

This should narrow down the leak.

[GLHNSLHT2]

Quote:

Originally Posted by crazymadbastard gotta pull that pump out, I am not familiar with the older fuel system but my gues is that maybe the pump is twisted such a way that it can suck in air or maybe somewhere along the body of the pump housing you have a crack and suck in air there. is this the setup? lots of plastic to crack

Similar but not quite. My system had the large bosch pump stock. So the Walbro slides down in a foam sleeve with the sock sticking out the end. Which all sits in a plastic housing. The pump is metal and hooks directly to a short piece of hose which then hooks to the gas tank "cap" like in the picture. I'll take some pics Saturday.

[GLHNSLHT2]

Quote:

Originally Posted by puppet OK ... random wild theory time. Your static pressure is too high ... should be 55psi. I think you crushed the nipple on the FPR return loop.

What nipple? The one exiting the FPR? or the one on the hard line? On the 87-88 FPR I drilled the nipple thinner so I could put the flare on the end after sliding the tube nut and sleeve on all in a bridgeport (big accurate drill press). I then used Summit's Flare tool on the hard line. I don't think I crushed it. The tube sleeve just barely fits over them. Then the tube nut pulls the sleeve against the back flare and presses it against the fitting on the hose.

But I've swapped to an 89 style FPR with a screw in fitting and nothing's changed. The static pressure has been 60psi since I put the original 255 in years ago. The 62psi out of the 89 style is because I dropped it right on the vacuum nipple side. I bent it straight just to use it temporaily. I have 2 good 89 FPR's on the way to me now.

Quote:

The pump sits in a reservoir inside the tank. The return line goes back to the tank and empties inside the reservoir near the pump. Initially, either the air is returning to the tank from the FPR or it's going to the rail from the pump. After it's running the pump will supply air if the return line is a fault. So you don't know which is giving you grief.

Ok so I'm thinking the same thing there.

Quote:

Do you know how to power the pump without the engine running Jay? The ASD relay powers it.

I run a wire from the battery to the positive side of the coil right? It's an 87 Daytona with 88 Smec electronics under the hood just for reference. How big of a wire do I need?

Quote:

I'd disconnect the return line at the tank and run it to a bucket ... power the pump and check for air coming back. If so, I'd disconnect the fittings at the FPR return nipple ... connect a length of hose and repeat the test. If you're still getting air disconnect the fuel supply line at the tank and connect a length of hose to the pump itself. Run it in a bucket and check for air. This should narrow down the leak.

Thanks Puppet. I'll get to it 1st thing Saturday morning.

[GLHNSLHT2]

Quote:

Originally Posted by jim34 I agree pull the pump out, you can have good pressure but the volume will be severely reduced if theres a leak in the tank

Agreed. I think I know why the FPR reg is so loud, when the diaphram hits an air pocket I bet it slams against it's seat where if it was constent fuel it's be pushed open all the time a certain amount.


Well, looks like I won't be going racing Saturday

[jim34]

You never know you can have that pump out pretty fast, I can get mine out in a few minutes probobly takes longer to jack the car up than to pull the pump out, support the car with jackstands and let the rear axle hang down and you can pull the pump assembly out without dropping the tank I cant remember if i had to loosen the strap bolts a little or not.

[GLHNSLHT2]

oh yea I can get it out pretty quick if I really want to. But racing starts at 10:30 am and I don't really want to rush it. I'd rather take my time and do things as close to correct as I can. Instead of rush it and blow something up

[crazymadbastard]

Quote:

Originally Posted by GLHNSLHT2 oh yea I can get it out pretty quick if I really want to. But racing starts at 10:30 am and I don't really want to rush it. I'd rather take my time and do things as close to correct as I can. Instead of rush it and blow something up

well stop posting and get to working on it!!!

[GLHNSLHT2]

I can't, I'm at work still I'm leaving early though to go get a couple things. Maybe I can do it tonight since the g/f is out of town.

[crazymadbastard]

Quote:

Originally Posted by GLHNSLHT2 I can't, I'm at work still I'm leaving early though to go get a couple things. Maybe I can do it tonight since the g/f is out of town.

That's the spirit, er I mean daytona!

[GLHNSLHT2]

ok Update. After a lot of gasoline I have ZERO air to the fuel rail. I've got a clear line going from the FPR to the return hardline. Soon as I supply power to the pump air goes through that line. I've tried 2 different FPRs. I had the fuel pressure gauge hooked up too and was bleeding air and fuel out it's purge line too. Any thoughts???


I have 2 more FPR's on the way to me which might be here tomorrow. Also I'm going to try and find a 3/8 pipe tape to hose barb adaper. Maybe i can bypass the FPR out the end of the rail and narrow it down to the FPR.

[jim34]

Is it just bubbles in the fuel or large gaps of air and then fuel ?

[GLHNSLHT2]

bubbles, lots of bubbles.