1999 Jeep Cherokee Issues

[Rubicon72]

My wife called me today and said the vehicle died in the middle of an intersection. I left work and towed her back to my house with my JKUR.

I tried diagnosing it but I am coming up blank and need your help.

Symptoms:

1. The jeep wants to crank over but it doesn't sound like it is getting fuel.

2. I have pulled all the spark plugs and put my tester on them to ensure there is no misfires happening. All checks out.

3. I then thought it was the fuel pump...since it is a common issue in Cherokees. I replaced it two years ago. I checked the fuel pump to make sure it still had pressure. I disconnected the fuel line next to the tank and made sure it shot fuel out during the priming process and while I was turning the key over...which it did.

4. I then checked the fuel rail. I hooked my pressure gauge up to the rail and it read "0" while I was cranking it over but fuel did come out of the opening.

5. I sprayed some carb cleaner in the air intake and it fired right up...and then died...

6. I have spark, I have air, it has got to be fuel. The only thing I can think of is there is a plug somewhere in the rail which is not getting to the injectors...

Any help would be greatful! I have a time set up at the dealership on Tuesday but I am hoping I can fix the issue before then. Nobody likes paying the stealership for simple fixes!

 

[Rubicon72]

My wife called me today and said the vehicle died in the middle of an intersection. I left work and towed her back to my house with my JKUR.

I tried diagnosing it but I am coming up blank and need your help.

Symptoms:

1. The jeep wants to crank over but it doesn't sound like it is getting fuel.

2. I have pulled all the spark plugs and put my tester on them to ensure there is no misfires happening. All checks out.

3. I then thought it was the fuel pump...since it is a common issue in Cherokees. I replaced it two years ago. I checked the fuel pump to make sure it still had pressure. I disconnected the fuel line next to the tank and made sure it shot fuel out during the priming process and while I was turning the key over...which it did.

4. I then checked the fuel rail. I hooked my pressure gauge up to the rail and it read "0" while I was cranking it over but fuel did come out of the opening.

5. I sprayed some carb cleaner in the air intake and it fired right up...and then died...

6. I have spark, I have air, it has got to be fuel. The only thing I can think of is there is a plug somewhere in the rail which is not getting to the injectors...

Any help would be greatful! I have a time set up at the dealership on Tuesday but I am hoping I can fix the issue before then. Nobody likes paying the stealership for simple fixes!

All research pointed to the CPS sensor. Bought a new one and replaced it. Still the same issue.


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[Saints&Sailors]

Is the pressure gauge on your fuel rail still reading zero? If there's no pressure there, there won't be any fuel in the cylinders.

Have you pulled the spark plugs and performed a compression test yet?

 

[Overland-Indiana]

All research pointed to the CPS sensor. Bought a new one and replaced it. Still the same issue.


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It can be pushing fuel through the lines but not with enough pressure to open up the injectors. You may have a weak fuel pump.

 

[Rubicon72]

Is the pressure gauge on your fuel rail still reading zero? If there's no pressure there, there won't be any fuel in the cylinders.

Have you pulled the spark plugs and performed a compression test yet?

I changed out new spark plugs and still nothing.


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[Rubicon72]

It can be pushing fuel through the lines but not with enough pressure to open up the injectors. You may have a weak fuel pump.

It is at the dealership now. The weak fuel pump could be the issue. I just changed it out two years ago. It could just be a week stream.


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[Rubicon72]

It is at the dealership now. I will let you guys know what the results are.


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[Saints&Sailors]

I changed out new spark plugs and still nothing.


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Changing the spark plugs is different than performing a compression test. A compression test will indicate whether each cylinder is holding compression. Engines work by taking air, compressing it with fuel and igniting it via spark plug. If you have bad valves or worn pistons, you'll have low or no compression.

Also, if your fuel rail pressure is still zero, there won't be enough fuel getting into the cylinders for combustion. You'll need to address this.

 

[Rubicon72]

Turns out my pump was working but it had light pressure. Only producing around 10lbs instead of the 49lbs. Hopefully I will be able to replace it this weekend. I will be doing it myself since the stealership wanted $900.00

 

[Rubicon72]

Replaced the fuel pump and the jeep runs perfect. It got even better because the fuel pump was warrantied for life by Advance Auto Parts. Just walked in there and got a free pump. Basically fixed my wifes jeep for free and all it cost me was a about two hours of labor. Overall the pump would have cost $165 if I were to have bought it new. Biggest issue I had was dealing with all the rust underneath the jeep.

 

[The other Sean]

Good to hear.

I got tripped up by a weak fuel pump years ago on a carbureted car. It would start and run fine and drive around town just great. But, as soon as you leaned on the skinny pedal, it would sputter and stumble for a few blocks. I had plenty of fuel pressure in the driveway. It wasn't until I duct taped the fuel pressure gauge to the windshield and went for a drive that I figured it out.