Fuel Gremlins

[moab4x4]

Like Pete says, you can use an electric fuel pump to test flow. That is also an easy way to empty the tank. I disconnect the fuel line from the lift pump and insert a piece of 3/8 copper tubing. The oring in the plastic fuel line connector seals nicely. I then use 3/8 rubber hose to my electric fuel pump.

Once the tank is empty, only you can decide whether to drop/inspect it or just fill with good fuel. I am paranoid and like to do things the hard way so I would pull and inspect it.

If you do that, you can then put that electric fuel pump on the tank side of your fuel system and pressurize it to look for leaks in the fuel line through to the IP.

BTW, not all leaks can be found that way, just the big ones. I had a small one that would make me have to crank and crank if I didn't drive for 2 days. It turned out to be a very small air leak between the lift pump and the IP. Took a month or two to find. (by accident of course)
Ken

[Begle1]

So as I'm draining my tank, there is a continous spray of little bubbles coming out of the line. Wouldn't that imply an air leak? There's a stream of tiny, barely visible bubbles and then occasionally one or two full-size bubbles... I'm pulling the fuel out from before the lift pump...

And how does bad fuel cause a vehicle to loose prime?

[PToombs]

Yup, bubbles is an air leak! You need to find if it is in the line, or the pump you added in.
Bad fuel won't. Don't understand why you asked?

[Begle1]

Bad fuel won't. Don't understand why you asked?

Because the problem that I've been having is that the vehicle stalls and won't start until I prime it?

I took a few gallons out today when I noticed the bubbles; it didn't look gamey at all.

Only connection that I haven't ruled out yet is, ironically, the one I need to drop the tank to get to...

[PToombs]

Well, you know how Murphy works, the last thing you check will be the problem!

[Begle1]

What's the best way to pressurize the system and look for leaks?

If I hook an electric pump in between the tank and the sender line, would the pressure hurt the piston lift pump? Would the lines pressurize past the piston lift pump?

Is there any chance that my injection pump is fubared? Because it's getting to the point where I wouldn't mind throwing money at the problem so that it'll go away...

[eyoung429]

Find a plug for the filler neck - I took a locking gas cap and drilled out the tumbler and soldered in a fitting.
insert a shreider (sp?) valve
use a bicycle pump!!!! to pressurize
Watch lines for weeping!

Do NOT use a regular air compresser.........I learned the hard way.

[Begle1]

Is that the normal way?

Beats the hell out of playing around any more with this chincy electric fuel pump.

I think that I've spent 5 hours trying to put this damn fuel tank back up underneath the truck. I'm about ready to throw a match into the entire thing.

But then I need to drive a Kia Sorento to the store that has a license plate which reads "GMA X 9", and I realize that I do still kind-of like my truck.

[eyoung429]

forgot, make sure that you have fuel in the tank....you can listen for hissing and do the old hand soap at every connection but it's faster if you have fuel to show where the leaks are.

[Begle1]

Oh yes, I HAVE FUEL IN THE TANK.

Don't need to worry any about that one...

[PToombs]

Fuel will push past the LP, check valves will open that way. It will pressurize the whole system.
EY, shrader valve.
I used air on my tank, but had the regulator set for 5? somewhere around there! Plastic does funny stuff that you don't want to experience with the tank full!
Begle, maybe drain some fuel out for ease of handling?

[Begle1]

I pressurized the system (using a fuel pump), could't find a leak. Put the tank back in, then it seemed fine.

Of course, while I was testing it, I lost the ability to shift from 1st to 2nd gear. And I think my blow-by has increased by an order of magnitude ever since the ether incident.

Mechanic buddy suggested that the hose I was using was sucking shut, starving the engine of fuel until I lost fuel pressure, and then giving it air once it opened back up. Which is the best explanation I've yet recieved. So I replaced the entire fuel system with a single piece of 3/8" steel-reinforced hydraulic line rated at 3000 PSI.

How the Hell is 3000 PSI steel-reinforced 3/8" hydraulic line the same price as flimsy rubber 5/16" fuel line?

Then I got the tank back up and my fuel gauge was stuck at "FULL".

Took a few minutes to figure out that the steel mesh in the new fuel line I installed was shorting out the sender to the engine. Oops. So I had to put a nylon washer on the barb to keep the mesh from making contact.

I think that problem is fixed. Damn truck is still falling apart around my ears, though.

[PToombs]

Well, I hope you got it. Intermittant problems suck! Ether is really not good stuff for an engine. I hate using it, but sometimes ya gotta! If the blowby increased, you might have scored the walls a little. Maybe it's just your imagination?
Remember, fix stuff 1 at a time, works better that way!

[Begle1]

Ether's really not good when it takes your engine to 4500 RPM with stock valve springs...

[PToombs]

Ether's really not good when it takes your engine to 4500 RPM with stock valve springs...

Ya think? I'd be more worried about bending a rod, or popping the HG. Still not good though. Be more careful next time, only shoot a little!