CAEMI

If I disconnect the fuel line between the tank and pump and crank the engine, should fuel flow out?

I'm trying to diagnose why my '94 XJ won't start...but if I dribble a bit of gas into the TB plenum, voila, it runs. I'm figuring fuel pump.

fishtaconc

it should sray everywhere, but you do not need tot do that there is a schrader valve on the fuel rail you should have pressure there you can rent a fuel pressure tester from autozone you should hve 31-39PSI at the rail IIRC

CAEMI

Thank you for the fast answer.

So, if I crank it over and have nothing spraying out, the fuel pump is bad - correct?

I suppose I have to drop the tank to get at the pump. Naturally, it is full right to the brim with gas. Any advice on how to make this job less unpleasant than I'm thinking it is going to be?

Turbo X_J

Check for 12 volts @ the pump before you tear it up. If it is the pump you can carefully siphon the gas out into approved containers. Please do not try as a local gent did to use a shop vac to remove the fuel, it did not end well.

fishtaconc

Before you start dropping the tank ,have you checked the fuse, relay? to make it easier get someone else do it...just kidding try to empty it as much as possible. try searching ballast resistor also

CAEMI

LOL. Reminds me of the story of the gas thief who lit a match to see if the can was full yet.

CAEMI

Seems to me I remember a car that had a fuel pump lockout that triggered if the car got hit or bumped hard. Mine tripped once and the reset button was up under the cowl on the passenger side of that car.

Is there a similar relay on the XJ? Where's it located - or where is the relay you mention located? Also where is the ballast resistor you mention and how do I test it?

Also, the only ballast resistor I remember was on my 1970 Chevelle SS and was the ignition resistor. I remember it well because a wire came loose from it at the Ubly Drag Strip one day and there was No Joy in big block land. Some guy walked by and pointed at it and said "hook that back up, man". Couple minutes later I was back in line. I didn't even know what it was for. Oh well...can't know everything.

BTW, thanks to all for the help. I'll do a search, too.

CAEMI

OK. Swapped the relays, no joy. No blown fuses. Turn the key and I hear nothing. After I get a little real work done I'm gonna measure voltage at the pump.

Questions:

Can't find the ballast resistor - anybody know where it'll be on a '94?

Real stupid question...what's the Schrader valve look like?

Finally, anybody know what the little vacuum doodad next to the dipstick is? (Not next to ME, the dipstick in the CAR.)

Gracias.

wildspear

Ford escorts in the 80's had those safty switches. used to mess with a buddy, I'd go past his car, kick the bumper and get a laugh out of it seeing him trying to start the darn thing.

CAEMI

That's the one! My wife had an Escort and if you looked at it crossways it would trip that button. Come to think of it, she was pretty much the same way.

CAEMI

I checked for voltage at the pump and it read 6.3 volts from the middle wire to ground. I checked the terminals at the fuse block - the connector terminals into which the relays plug - and got a nice 12.49 volts on the hot wire on each live plug.

I swapped relays around and no change. I checked all of the fuses, all are fine. I traced out the wiring from pump to fuse box and all appears just fine.

I cannot find a ballast resistor anywhere on the truck. I DID find the Schrader valve - simple little thing in the middle of the rail.

I put my stethescope to the pump and had my son cycle the key...not a whisper.

So: Does it sound like a bad pump?

ET JEEP

The feed voltage of 6.3 seems low. You should read the same voltage you got at the relay. Run a fused wire with an on-off switch from battery positive to the fuel pump connector. Ground the pump and turn the switch on. Your pump should run. If it does, you have an electrical issue in the feed line. If it does not run, bad pump. Still, that feed voltage seems low.

a.dickens

Try swapping more than 1 relay. I found I had 2 bad relays because I swapped one and it didn't work and so I went through the fuel pump swap and it was not the fuel pump but the fact I had 2 bad relays.

Here is what you are going to have to do if you need to change your fuel pump. I just did that this past weekend, and am not claiming that my way is right, perfect, and the only way to do it-only that it is the way I did it.

I had a full tank of gas that I had to PUMP out. My '88 XJ had an anti-siphon feature that I am certain your newer model has. So, I had a fluid pump that I got from Sam Walton's General Store and attached the hose line to the outgoing fuel line and pumped 15 gallons out. 10 went into my wife's car and 5 stayed in a tank for when I was done.

Next I climbed under my Jeep and used a brass punch and a hammer to rotate the locking ring. I didn't need to drop the tank, I don't know if you will have to or not. All the things I read said to tap the ring counter clockwise to release the ring. Mine got jammed/stuck as I was tapping it counter-clockwise but the ring didn't come out until I hit it clockwise. I've got a backwards Jeep I guess. Once the ring is off (which to me was the hardest part), slide the fuel pump out. Pay attention as your are pulling the pump out because you have a rubber floater that gives your Full/Empty reading and you don't want to mess that up. Also, make sure that you have the filter sock still attached. I had to go fishing for mine in my fuel tank because it fell off while I was pulling the old pump out.

Once you pull the old pump out, just put the new one in and slide the gasket to the tank, stick the pump in the tank, attach the retaining ring. Hook up your hoses, and you are done.

CAEMI

That's what I thought, too. The voltage did not change if the key was on or off and I never got more than 6.3 on the meter.

I'll try your idea and see if it works and report back tomorrow.

CAEMI

Excellent summary. I've tried three relays - including a brand new one - and no joy.

I got under there tonight and cleaned off the ring and removed the two fuel lines and unplugged the wiring harness. Got a face full of gas in the process...delightful.

I siphoned about 15 gallons out of my full to the brim tank and left a bit in there for starting. Then went to the parts depot and bought a Bosch pump and new filter. Got the filter on and I'm gonna tackle the pump tomorrow after I try the jumper trick mentioned above. Sure seems like the voltage is low. I'd like to not spend $90 on the pump, that is certain.