92 YJ New Fuel Pump - No Pressure

I recently installed a new fuel pump in my 92 YJ 4.0L. After getting everything back together the Jeep started right up and I drove it around with no issues. After parking it would not start again. I pulled the sending line and turn the key on. I could hear the fuel pump start but no fuel was coming out. I pulled the return line and turned the key on and fuel came out of the sending line. I reconnected the lines and the Jeep started again. After driving and parking I was able to restart it. I came out the next day and it wouldn't start again. I tried the previous steps but no luck. When I turn the key on I hear the fuel pump start but no fuel is coming from the sending line.

Any ideas?

Thanks.

Reply to
KH
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Didja replace the fuel filter too?

Kate

2O|||||||O6 Rubicon With a coupla flammywhammers bolted onto it.

Any ideas?

Thanks.

Reply to
Kate

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Reply to
L.W.(ßill)Hughes III

Yes, fuel filter has been replaced.

I pulled the line before the fuel filter and no fuel comes out when key is turned on and fuel pump starts.

Reply to
KH

Will give it a try.

Where is the check valve located on a YJ?

Thanks.

Reply to
KH

Ok.. ya confused me. (which isn't that hard to do but anyway) :)

This sounds like a kinked/pinched or blocked return line.

Just to make sure. (helps to have a gas can or hose to do this test so you don't waste fuel)

Pull the line after the fuel filter, have someone turn the ignition to on so the pump primes. Make sure the fuel is going to the engine and not the other way around. (from what I remember the connectors prevent you from hooking up the pump backwards, but check anyway) If fuel comes from the engine side than something is backwards.

The return port on the fuel rail is across from the pressure regulator at the front of the fuel rail.

Another remote possiblity is that somehow the fuel tank vent is stuck. Take the gas cap off next time it does this. Usually though this only causes problems on trips long enough to drain a gallon or two out of the gas tank.

Check the tank to make sure the return line didn't get pinched.

Reply to
DougW

Okay, tried turning the key on and off.

The fuel pump will start the first few times but then won't start again unless I let it sit for a while or crank it over.

I have a fuel pressure gauge attached to the fuel rail and I'm not getting any pressure no matter what I try.

I disconnected the lines at the fuel rail and I was able to blow air down the return line and it sounded like bubbles were making it to the tank so I think it's clear.

I did notice that the fuel gauge is stuck at Full. Not sure if that means anything.

The fuel pump, fuel tank vapor vents, and hoses from the tank to the fuel lines are all new.

Could it be a bad fuel pump even though it's new and sounds like it starts when I turn the key on?

I was hoping that I wouldn't have to drop the tank again but it looks like I might have to check things out again.

Thanks for all of the responses.

Reply to
KH

Dunno about the 92 YJ, but does it have an override switch that turns the pump off in a couple seconds if it detects no line pressure? Know newer systems do.

If you get bubbles, that would seem to eliminate a vacuum lock on the supply side. How close to the pump outlet can you get, to check flow?

Reply to
Lon

Okay, tried turning the key on and off.

The fuel pump will start the first few times but then won't start again unless I let it sit for a while or crank it over.

I have a fuel pressure gauge attached to the fuel rail and I'm not getting any pressure no matter what I try.

I disconnected the lines at the fuel rail and I was able to blow air down the return line and it sounded like bubbles were making it to the tank so I think it's clear.

I did notice that the fuel gauge is stuck at Full. Not sure if that means anything.

The fuel pump, fuel tank vapor vents, and hoses from the tank to the fuel lines are all new.

Could it be a bad fuel pump even though it's new and sounds like it starts when I turn the key on?

I was hoping that I wouldn't have to drop the tank again but it looks like I might have to check things out again.

Thanks for all of the responses.

If your fuel gauge is stuck on full, there's your notice that you have some problem in-tank.

Drop the tank, pull the pump/sender, make sure nothing's in a bind including all the lines.

Then, before you go through reinstallation, I'd set up and secure it, and see if you have the problem fixed by repeatedly starting the Jeep until you're sure that both problems are taken care of.

Spdloader

Reply to
Spdloader

Okay, tried turning the key on and off.

The fuel pump will start the first few times but then won't start again unless I let it sit for a while or crank it over.

I have a fuel pressure gauge attached to the fuel rail and I'm not getting any pressure no matter what I try.

I disconnected the lines at the fuel rail and I was able to blow air down the return line and it sounded like bubbles were making it to the tank so I think it's clear.

I did notice that the fuel gauge is stuck at Full. Not sure if that means anything.

The fuel pump, fuel tank vapor vents, and hoses from the tank to the fuel lines are all new.

Could it be a bad fuel pump even though it's new and sounds like it starts when I turn the key on?

I was hoping that I wouldn't have to drop the tank again but it looks like I might have to check things out again.

Thanks for all of the responses.

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Reply to
L.W.(ßill)Hughes III

It's looking closer to a problem like missing the baffles and pinching the supply line that's down in the tank. That's an issue with the

93 ZJ and might be the same in the 92YJ since it borrowed quite a bit. The service book is real picky about getting the pump orientation perfect.
Reply to
DougW

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