My 91 Cherokee has sat for a couple of months, and I went out today to get some maintenance done for the winter. It started up fine, but it only ran for about 30 seconds before it died. Tried starting it back up, and it's not working. It's got a good battery, starter is cranking, and I can hear the fuel pump priming when I turn the key in the ignition.

For reference, the fuel gauge has been acting funny for some time.. it will go down to empty and the light will come on when I start the Jeep, then as I drive around it will go up to the correct level. currently, the gauge is showing empty, but I added a couple of gallons of fresh gas and it's still not moving and not starting. Is this something that could be caused by something as simple as a fuel filter, or am I probably looking at a more serious issue? Where do I go from here?

 

Checked for spark? Kind of unlikely you would lose it right then but you still wanna check.

 

best way to do that? Pull a spark plug wire and see if it sparks when I turn it over?

 

Yeah just leave the plug in the wire and ground the electrode to the block or you can also get a spark tester that goes in between the wire and plug. That's a safer option.

 

I do have spark, though I'm going to need to buy a new wire now. The metal part of it that grips the spark plug didn't come lose, and just pulled right off the wire when I pulled. Had to use pliers to get it off the spark plug. But at least I know that works.

 

A faulty "crankshaft position sensor" can also cause problems with the fuel gauge when it fails in a certain way. I've seen it. Check out this link.

http://www.jeepforum.com/forum/f11/c...ailing-639123/

Because you are having a symptom of keeping the engine running AND the fuel gauge issue, I would highly recommend replacing your crank sensor. Buy it directly from Jeep. No lack of threads with people having issues with aftermarket ones. Spend the extra $20 bucks. Money well spent in reliability/longevity.

 

I did a few of the tests to see if that's the issue, and it doesn't seem that way. From what I read, the gas gauge should have worked immediately after unplugging it, and the Jeep had a good chance of starting up normally after I plugged it back in. Neither happened. I'll break out my multimeter in the morning to check resistances and such, but right now it looks to be something else. Thank you for the tip though, I'm sure i'll run into that issue sooner or later.

 

I test for fire at the coil.
Just pull the coil wire and use a long screw driver and touch it to the body and hold it close to the coil electrode and crank it from the starter relay with the key on.
If you got good spark there could be bad plug wires.
if no spark, find the connector to the CPS (Crank Position sensor) unplug it and plug it back in. See if it stats if not, you need to check it with a multi-testor.

My 87 XJ occasionally will fail to start, I just unplug the sensor and plug it back in and its golden again, WHY? I have no idea. I even showed the wife where it was. She seen me do it once and asked why. Then she started doing the same thing if it happens. hah.

 

Well, I have a spark, I changed out the fuel filter, and checked the CPS with my multimeter, and all are okay. Still just turns and turns. A couple of times it coughed like it was going to start up, then just went right back to cranking. I can hear the fuel pump priming.. is there any way to check to make sure it's actually working? When changing the fuel filter, my repair manual said to relieve the pressurized fuel line by using the valve on the pressure test port, and implied gas was going to shoot out when I did that. I could hear it bubbling a little, but didn't get any liquid out.

 

That could be your problem.

 

If you have no pressure at the fuel rail, that IS your problem.

If you can hear the pump "energize" and run for about 2 seconds when you turn the key to the ON position (as designed) and you have no pressure at the rail, you have one of two things going on.

1. An extremely clogged fuel filter

2. A bad fuel pump

 

Must be the latter then. I replaced the fuel filter. Would explain the gas gauge reading incorrectly as well, huh? That something easy to fix for someone inexperienced, or since there is gas involved would I be better off taking it somewhere? Do you have to drop the tank?

 

You're sure you are not out of gas? If somehow it was dry two gallons might not be enough to pick up. There has been more siphoning with the price of gas so high. Are there any teenagers within 50 miles? And; once the pin that drives the impeller in my fuel pump wore out. The motor would run, but of course it wouldn't pump.

>>>bubbling a little, but didn't get any liquid out. <<< You might also make sure the line is OK, not chewed by gerbils or anything, sucking air.

 

The fuel pump is super easy on the pre 97 xj's. It is located on the side of the tank facing the front so you don't have to drop it. There is a metal lock ring with three tabs that secure it. Take a brass punch (or regular screwdriver if you're dumb like me) and place it against one of the tabs and using a hammer, punch it couterclockwise until it releases from the retaining tabs on the tank. Pull old pump out. Install in reverse. Oh don't forget to disconnect the electrical harness and be careful when putting the new one in not to smack the float around in the tank.

 

If you can, pressure wash under there some first. I ended up with an earful. Disconnect the battery. I'd want to have less than 1/4 tank. A piece of brass pipe could make a nice drift. Even small sparks there is a big no-no.