mudgirl

Its '90, the engine starts and dies almost instantly. I heard some one say it could be my fuel system. Some care to explain please. Blonde terms, Im no mechanic.

Radi

If it dies right after starting, check the ballast resistor on the firewall. You can bypass it entirely and connect the wires at each end together.
If it's bad your fuel pump will run while you hold the key in "start", but not anywhere else.

This thread has a good picture of the ballast resistor:
https://www.cherokeeforum.com/f2/tro...j-8699/index2/

mudgirl

thanks!! so how hard is it to change the fuel pump?

Radi

I haven't changed one on a '90, but most years you can do without dropping the gas tank. The pump is mounted on the (front) side of the tank.
Is the fuel pump bad?

Green87

The proper way is to drop the fuel tank. Then the fuel pump/sending unit will be right there on top of the tank.

I have seen it done too many times where the owner doesn't want to take the time to drop the tank and cuts a hole in the floor of the trunk area and access the fuel pump from above. Not only is that an ugly way to do it, it allows exhaust fumes to enter the inside of the vehicle.

I agree that it is a fuel issue. I don't know a lot about fuel systems either, so I usually take it to a mechanic.

mudgirl

Had my brother look at it just a few min ago and he said that seems to be the only thing he can think of but hes never replaced on one a Jeep..hes a chevy man.

Radi

Why would you be dropping tanks or cutting holes? The pump isn't on the top of the tank.

Before you condemn the fuel pump, check or bypass that ballast resistor first.

Typical pump location:

tjwalker

I agree with Radi. You MUST verify that the ballast resistor is not the root cause before condemning the fuel pump itself.

By design, the ballast resistor is "out of circuit" when the key is in the full start position so the engine gets fuel. But when the key is released and springs back to the run position the ballast resistor is now back in circuit.

So if that resistor is bad, it will allow the engine to run for a bit in the full start position, but die as soon as you release the key.

Try jumpering that resistor with a small piece of wire. It is not an issue to do this, the resistor is only there to reduce noise on the fuel pump circuit; later model XJs don't even have this resistor; the mfg. deleted it.

cruiser54

The resistor is a white ceramic thingy about 3" long near the air cleaner on the driver side inner fender. Has a wire connected to each end. Make sure the connectors are tight. Jumper it if that's not the issue.

cruiser54

Correct Radi. No need to drop the tank.

mudgirl

Its been eliminated down to the fuel pump problem, thanks you guys.

tjwalker

When you buy your new fuel pump, do NOT buy an Airtex. IMHO, they have a big time reliability issue with their fuel pumps. My favorite brand is Bosch, followed by Carter.

Good luck!

DFlintstone

Like the guys said, the rear wire on the ballast resistor goes right to the pump. If that has power, and the pump ground is OK, and still no go, you can change the pump with the tank in the Jeep.

A note, no sparks! (and have less than 1/4 tank). Wood or brass to turn the ring. THEN it's dicey business extracting it with the filter and gauge. Take a little time and feel gently as you turn it this way and that to get it out. (without catching the fuel strainer on something and ending up with it in the tank)

Lots of stuff might end up in that blond hair you mentioned if you don't have an opportunity to spray and wash up there around the filter and pump first. Working under there, everything falls right on you.

Since I've joined the forum I've seen that you might clean the contacts in there somewhere for the gauge. (with alcohol). I wish I'd have known that when I had mine out, as my gauge only works below 1/4, and over 1/2.