Jeep 4.0 fuel issues? Maybe?

NotSoPC · Oct 18, 2013

So I have a 98 TJ 5spd. I replaced the fuel pump about two months ago. After about a week I am having what I think is fuel issues. It has long cranking starts that seem to be shorter if I pump the gas a little. Can't go over 2900rpm cause it will cut out. Bogs coming off the line in first and sometimes when in second. Runs ruff for a minute or two after starting and shudders when I give it gas right after start like it has a couple dead cylinders them smooths out. Today it bogged while making a right hand turn in third and I had to press the clutch and rev it up a bit then all was fine. Any ideas what to start with? On a budget so I don't want to be replacing the fuel pump again if I don't have to. Any help would be great, thanks.

Avanteone · Oct 18, 2013

Put a fuel pressure gauge on it and see what it does. Did you replace pump only or the entire module?

NotSoPC · Oct 18, 2013

Avanteone said:
Put a fuel pressure gauge on it and see what it does. Did you replace pump only or the entire module?

Replaced the whole set up in the tank. Could it be an air leak in the return lines to the tank maybe? I was also told about a plunger type deal in the intake side that gums up. I have not spent a whole lot of time on the 4.0s for a while.

Avanteone · Oct 18, 2013

Long cranking to me means fuel pressure. Bogging on accel sounds like fuel pressure. Bogging on corners sounds like fuel delivery. I'd want to put a gauge on it, but I'm guessing it's probably a problem with the pump itself or the installation of the pump.

NotSoPC · Oct 18, 2013

Ok, well I will pick up a gauge tomorrow and see what I get. What should I be at or around? The pump I used was cheaper then most cause I was on a budget when I replaced it and needed to get it done in a hurry.

NotSoPC · Oct 19, 2013

By the way, what are the two deals that are on the right and left sides of the tank? Was told they are roll detection things?

Avanteone · Oct 19, 2013

NotSoPC said:
By the way, what are the two deals that are on the right and left sides of the tank? Was told they are roll detection things?

On the top of the tank? Just breathers.

NotSoPC · Oct 19, 2013

Avanteone said:
On the top of the tank? Just breathers.

Ya they are on top on the left and right sides and come together at a T fitting, and then the tube follows the fuel line.

hoeynoey · Oct 20, 2013

I wouldn't rule out a chance of a loose electrical connection both the main + & - on the block and the starter.

NotSoPC · Oct 20, 2013

hoeynoey said:
I wouldn't rule out a chance of a loose electrical connection both the main + & - on the block and the starter.

Looked at the grounds and connections yesterday and all look good. cleaned a few up and made sure all were tight. I still need to check fuel pressure but have to buy a gauge first. That's about all I have left at this point. Thinking its the pump being ****. If that's the case then I will have to do the 19 gal mod while its out this time as I forgot to do it last time.

Avanteone · Oct 20, 2013

NotSoPC said:
Looked at the grounds and connections yesterday and all look good. cleaned a few up and made sure all were tight. I still need to check fuel pressure but have to buy a gauge first. That's about all I have left at this point. Thinking its the pump being ****. If that's the case then I will have to do the 19 gal mod while its out this time as I forgot to do it last time.

I see you're in Milton. If you wanted to swing down to Auburn with it, I'd be happy to throw my gauge on it and go for a drive.