BIGCOOK

I got a question for y'all. On my 93 xj the gas hose where you fill it up, its got another hose that's small about 5/8 and it keeps gas from spitting back. The question that I have is the fuel pump has to build pressure in the tank but if the 5/8 hose is missing would it let the pressure out the tank? So it wouldn't let it pump gas up to the fuel rail would it?

Grip

i think it will still pump gas as long as the pump is submerged in fuel enough to suck up gas.

iirc the 5/8" hose is a burp hose to let air out of the tank as you fill it with fuel.

jomps

I would think you need it for optimal use because that is why its there but sure about negatives to not using it...sorry that doesnt help but now you got me wondering

BIGCOOK

Yea I know it looks like a dog got a hold of it but it still goes into the tank so it wouldn't let the fuel pump build the rite pressure would it?

azhobo

"The question that I have is the fuel pump has to build pressure in the tank but if the 5/8 hose is missing would it let the pressure out the tank?"

If I understand your question, I have an idea you don't have the theory down exactly right.
The fuel pump doesn't pressurize the gas tank, it puts pressure on the fuel line and fuel rail only. Your tank is thin plastic, so would not respond well to being pressurized. The hose being missing won't affect anything, unless possibly passing emissions testing. I would suggest you replace it ASAP however. Like Grips says, it's a vent to let air out as you fuel.

HTH
Bob

BIGCOOK

Ok I was wanting to make sure cause I'm still trying to avoid dropping the tank but I know it needs to be done cause gas isn't getting to the fuel rail

azhobo

"cause gas isn't getting to the fuel rail"

Do you know if the fuel pump runs? You should be able to hear it run when you first turn on the key. That's the first thing to determine, then more checking if it does run.

BIGCOOK

When I turn the key on the fuel pump kicks on like it should but there is nothing at the fuel rail. I did pour a lil gas in the intake and it ran for about a minute or so but it was starving for fuel

azhobo

First thing to check is to see if your missing hose has let the gas in your tank evaporate. In other words, out of gas. That's why I recommended you replace that hose soon. I have no clue what year your Jeep is, but making the assumption that it's common, that hose comes up inside your gas cap, keeping your gas sealed in the tank. W/O the hose, outside air can enter the tank and evaporate your gas. Verify that you even have gas available.
Could also be a blocked intake screen on your pump, lifting bypass valve on the pressure side of pump, or just plain wore out pump.
Have you checked to see if you have gas flowing in the line before the rail?
Process of elimination here. Not a difficult system, just get a plan for
T/S' ing, and you should find the problem in short order.

Good luck with it.
Bob

BIGCOOK

Thanks ill give it a try and see how it goes

89Renix

this sounds really stooopid... but fuses?

Grip

Could be a blockage in the fuel line, crushed fuel line, really dirty fuel filter.

I would first look at the fuel pump. Have a buddy get in the car and cycle the key to ON while you lay under the tank. You should hear the pump run for about 3 seconds while it pumps fuel to the injectors. If it doesnt, replace the pump. Also look at the fuel pump relay, and the fuel pump fuse.

Always start with the easy stuff.

BIGCOOK

I've checked the fuses with a test light and I can hear the pump I'm gonna take and use the air compresser to blow back Thu the gas line

Grip

Fuel filter?

BIGCOOK

I haven't had a chance to check it yet but it won't hurt to spend 10 bucks on a new one