Fuel pump runs, but no fuel pressure?

[horizontalkev]

Rewired walboro 255 fuel pump and Aeromotive fpr and aftermarket fuel lines.

When did this happen? Car was running strong, shut off motor and 10 minutes later started it up again, sputtered and slowly died. Cranks over, but no start afterwards.

What have I tried? Bought a new relay, fuel pump fuse is okay and I've turned on the fuel pump manually and it ran. I can also hear it running while trying to start the car.. I am not showing any fuel pressure and not getting fuel to the fuel rail.

I have half a quarter of fuel left. What the heck is wrong?

 

[grudgedoutgsxr]

Mke sure you prime the system. Of cycle the key a couple times, so the fuel pump can get the gas to the rail, then start it. It may take up to 5 secs.

 

[WES_393]

Have you checked the hanger assembly? If the pump lost it's seal at the bulkhead, then it would just dump the fuel back into the tank.

 

[5150DSM]

Have you physically verified that you are not just out of fuel. Gauge could be off, stuck float arm, bad signal to gauge, etc...

 

[boarderlib]

Have you checked or changed your filter lately?

When my pump starting shitting the bed on me, it acted the same way. It would run fine. I would shut it off, and by time I got back in it to start it. It wouldn't start.

 

[horizontalkev]

Mke sure you prime the system. Of cycle the key a couple times, so the fuel pump can get the gas to the rail, then start it. It may take up to 5 secs.

I primed the hell out of it and tried starting it till the battery died.

Have you checked the hanger assembly? If the pump lost it's seal at the bulkhead, then it would just dump the fuel back into the tank.

Well the day before his problem happened (last week) I did remove the fuel pump just to do it (first time) what do ou mean lost its seal at the bulkhead?

Have you physically verified that you are not just out of fuel. Gauge could be off, stuck float arm, bad signal to gauge, etc...

I think its starting to look as if I may have to remove the pump again, ill verify there actually is fuel

Have you checked or changed your filter lately?

When my pump starting shitting the bed on me, it acted the same way. It would run fine. I would shut it off, and by time I got back in it to start it. It wouldn't start.

I removed the fuel filter and tried turning it over without any results. This problem happened to me suddenly, and hasn't started since.


** FIXED IT FOR YOU **

 

[horizontalkev]

Gofer, Thanks for fixing the posts for me! Just an update, I was told with the "saddlebag" design of the fuel tank on the awd cars that there could be fuel on the drivers side of the tank, but none on the passenger side where the fuel pump is (if the siphoning system failed), and this is why my gauge would show I have fuel, but not push any. Any way to confirm/fix this without removing the fuel pump again?

 

[DAO 1950]

The float is attached to the pump assembly so that wouldn't be a worry. It's more than likely something that happened during your pump remove and install

 

[c2ypt1c]

If the pump lost it's seal at the bulkhead, then it would just dump the fuel back into the tank.

Agreed.

OP check the rubber o-ring that slides onto the nose of the pump. You can blow (lightly, and don't inhale) on the end of the fuel line to verify that it's sealed properly.

 

[get_boosted]

I had a similar problem with a walbro 255 where it would no longer build pressure. Replaced it with a 450 and everything is good now

 

[Abe'sGST]

Just remove the fuel pump assembly and check to make sure everything was done fine.

 

[horizontalkev]

Thanks everyone, I tried to add fuel to the tank and that didn't work so ill take it apart and look it over. Also, during cranking I noticed I was getting fuel puddling on top of the sending unit where that middle line is between the other two lines. Could that have something to do with it?


Also should mention, I believe I may have messed up some wires coming from the ecu, my pinky toe hooked onto some wires down there as I got in the car, nothing disconnected though.. The problem happened the first time I started the car after that

 

[Breezio69]

Your best bet would be looking at all the harnesses on the ecu and making sure you didn't yank any pins out or loosen the connections. Sometimes when the pins are installed they are barely hanging on inside the harness, a good jolt could yank it back enough to look connected but not make a connection.

Doing stereo installs I've seen pin connectors come out just pulling the factory radios out. Its no big deal, just pull the pin out the back side of the harness, straighten out the barbs on the pin and flair them out a little and push the wire back through gently till it seats again...

That is if you have in fact damaged some wiring at the harnesses.

If you can't physically see anything at the harnesses then trace the wires that got caught.... why were they in a place you could snag them anyways?

 

[horizontalkev]

Okay ill look Im searching for a pin out guide to see which wires could effect fuel pressure and start with those. And I removed the kick panel exposing the wire harness, I was getting ready to yank the ECU out to inspect it.

 

[WES_393]

Thanks everyone, I tried to add fuel to the tank and that didn't work so ill take it apart and look it over. Also, during cranking I noticed I was getting fuel puddling on top of the sending unit where that middle line is between the other two lines. Could that have something to do with it?

Yes, that definitely points to the problem. Check all the fuel lines for cracks and leaks.

Also should mention, I believe I may have messed up some wires coming from the ecu, my pinky toe hooked onto some wires down there as I got in the car, nothing disconnected though.. The problem happened the first time I started the car after that

It would be a good idea to check the wiring since you yanked on it. But if the pump is running thats all that matters at this point. The ECU doesn't control fuel pressure so it's not like you tripped some kind of electronic relief valve. I'd focus on the sending unit and fuel lines before anything else.

 

[horizontalkev]

Thanks Wes_393, I will tear into it tomorrow. I wonder what it could have been if it were from me removing the fuel pump in the first place all I did was pull it out of the tank, I didn't remove it off the sending unit or mess with it.

I loved removing the fuel pump looking into a half tank of sketchy fuel while sitting in an enclosed area, felt like I was just above a bomb. Lol time to do it all over again tomorrow, wish me luck

 

[horizontalkev]

Okay got the fuel pump removed.. Couple of pictures, Im not sure but on the underside where the fuel pump meets the sending unit looks like JB weld that failed..

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[Breezio69]

That does look like some sort of failed epoxy, I don't know if its jb weld unless its painted?

But either way, if its broke and not sealing the pump will just push it out fuel at the crack and probably introduce air in the system while driving. I'd look for a new sending unit, or you could possibly fix it with a couple brass barb fittings and a rubber grommet. .. but I'd buy a new sending unit for piece of mind... I mean leaking fuel and any heat is sketchy.

 

[horizontalkev]

Im currently looking into buying a new sending unit and fuel pump.

The epoxy isn't painted, and Im not entirely sure what was used. Im using JB weld to redo the top and see if it'll seal the bottom (temporary).

Now what I don't know is if the epoxy underneath in the pictures is infact a seal for the fuel pump and is the reason Im having problems, or if its merely there to help seal the hole for the AN fitting and in the end still have problems. And is that really enough to completely prevent any pressure?

I need to redo all of it anyways because the previous guy who fabricated it is probably the type that yell "yolo" because its so poorly done I've already fixed a leak in it a month ago. And now this.

 

[grudgedoutgsxr]

Im currently looking into buying a new sending unit and fuel pump.

The epoxy isn't painted, and Im not entirely sure what was used. Im using JB weld to redo the top and see if it'll seal the bottom (temporary).

Now what I don't know is if the epoxy underneath in the pictures is infact a seal for the fuel pump and is the reason Im having problems, or if its merely there to help seal the hole for the AN fitting and in the end still have problems. And is that really enough to completely prevent any pressure?

I need to redo all of it anyways because the previous guy who fabricated it is probably the type that yell "yolo" because its so poorly done I've already fixed a leak in it a month ago. And now this.

That "yolo" part had me cracking up yo. Why don't you try to contact the guy who fabbed it?

 

[horizontalkev]

Well its a long story I bought the car from the brother of the owner who knew nothing about the car, and since I bought it I've never had contact with him again. So Im on my own

 

[miguelmcv]

Your problem is very easy to identify.

You have to check at the fuel pump,

First, Check how many volts you have at the fuel pump, I know you rewired it, But just to rule out the problem.

If you are getting 12vlts, then go ahead and disconnect the fuel line close of the fuel pump, Check the pressure coming out of it right at the fuel pump outlet, (connect a hose to a bucket so you don't spill it out.

If you have no pressure, then your pump is not good, or you have something blocking the passage at the pump outlet.

If you have pressure, then connect back the house and disconnect the hose at the fuel filter, (before the fuel filter), If you have pressure, then connected back and disconnect the hose after the fuel filter and so on.

Also, check that you have a good ground at the fuel pump location.

 

[horizontalkev]

Your problem is very easy to identify.

You have to check at the fuel pump,

First, Check how many volts you have at the fuel pump, I know you rewired it, But just to rule out the problem.

If you are getting 12vlts, then go ahead and disconnect the fuel line close of the fuel pump, Check the pressure coming out of it right at the fuel pump outlet, (connect a hose to a bucket so you don't spill it out.

If you have no pressure, then your pump is not good, or you have something blocking the passage at the pump outlet.

If you have pressure, then connect back the house and disconnect the hose at the fuel filter, (before the fuel filter), If you have pressure, then connected back and disconnect the hose after the fuel filter and so on.

Also, check that you have a good ground at the fuel pump location.

Thank you I will try this tomorrow and get back with you asap, If I don't I probably died in a fire. Crude and at best mediocre humor aside Im hoping my fuel pump does work. Thanks miguelmcv

 

[WES_393]

Now what I don't know is if the epoxy underneath in the pictures is infact a seal for the fuel pump and is the reason Im having problems, or if its merely there to help seal the hole for the AN fitting and in the end still have problems. And is that really enough to completely prevent any pressure?

Absolutely. That cracked epoxy disaster, along with the sketchy rubber hose and clamps, are certainly the cause of your issue. I would replace the epoxy and fitting with a proper bulk head setup like this:

Heres a 2g set up a local did who's pics i've taken so they didn't get deleted. He used a -8 and drilled it to accept the pump and also shortened the bottom of the bulkhead to fit along with the bulkhead nut.

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[horizontalkev]

I want to set it up like that as soon as I can, but the previous owner caked the top with epoxy and also the bigger hose clamp and hose ALSO has epoxy on them, and that hose clamp is wedged in there in a way I can't unscrew it. Im thinking its only coming out from the top, so it'll take some grinding. How do you connect the bulkhead to the fuel pump does it just kind of slide in there?