Hey there, so I have a 1990 Cherokee Sport L6 4.0L and I was driving it when the engine died. Tried starting fluid and it would run for a second until you stopped spraying the fluid. Deduced the fuel pump and so I replaced the fuel pump and fuel pump relay but it still only cranks. Figured loss of fuel pressure and sprayed some starting fluid and it only runs while spraying. Any help would be appreciated as I am new to this and the forum as well.

Also I am about 90% sure the fuel pump turns on but I'm still new lol. Thanks!!

 

Someone else more knowledgeable on this model year will chime in but, isn't there a inline fuel filter on the older models? I know on the newer XJs the fuel filter is built into the fuel sending unit.

 

My 89 has an inline filter... sure the 90 does as well.

Listen for the pump to prime. If there is power to it you will hear it spin up when you turn the key forward.

But yeah... pop that filter off of there and see if it is clogged... in fact, just go ahead and get another one. They are cheap.

 

Yea I'm sure that filter has at least 100K on it. Probably worth replacing even if it isn't the problem in the end. I file that under "general maintenance". Like changing your trans fluid or motor oil, etc.

Also, investing in a fuel pressure gauge would be a wise option. Attach it to the fuel to get your trouble shooting baseline. Then replace the filter and check again. See if your pressure comes up. 49PSI @ idle plus or minus 5PSI is the spec for 4.0s.

 

True dat!

I actually keep a spare in my "miscellaneous loose, spare parts and other junk I want to hang on to" bag in the back of my XJ.

 

For real though... the fuel filter costs around seven bucks. It's located by the driver's rear tire.

Takes about 4.38 minutes to swap.

 

You're slow....LOL.

Fuel filter change is every 30K miles also........

 

Also make sure there's gas in the tank...

 

Do you hear the pump run for a couple of seconds after you turn on the ignition? Btw, the wire from the rear of the ceramic ballast resistor (who's, connections and the resistor itself are known to fail), that wire from the rear goes straight to the pump. You might meter that while it's cranking. It's on the inner fender near the air cleaner.

 

So I went and looked at the inline fuel filter. That's dirty but my buddy found out my fuel pump isn't turning on. My fault. So we're going to re look at it and make sure everything is right. But thank you for the help and I'll update you on how it goes.

 

Make sure to check the relay to the fuel pump, its possible that could be your problem

 

Sorry for not updating you folks, been a busy past couple of days. But good news and bad news. Fuel is now getting to the fuel rail, we checked the fuel pressure and it's going, and there's fuel getting to the injectors too but it still doesn't want to run. When we spray starting fluid into the the throttle body it starts up but doesn't stay running even with fuel to the injectors. Anyone have an idea what that could be? We're going to see if the injectors are clogged but any ideas would help, this jeep is my baby!

 

noid light, confirm injectors are firing.

 

I has success using a bulb from a three cell mag light as a noid light to check injector pulse. Utube of it here > Utube > https://www.youtube.com/watch?v=nPdk...ature=youtu.be



Or you could go this way with it, NO SPARKS!

 

A test light works................

but, we still don't know how much fuel PRESSURE.