YJ with XJ 4.0 problems

[jesswilliams]

I hope someone can help me here. I have a 90YJ with a 97 4.0 installed and it has a mopar computer that has a Carb# and emissions exempt tag. My problem is that it was my fathers and he recently passed away and I am trying to sell the Jeep but it started having some issues. He never had a problem with the Jeep but I was driving it yesterday and it started surging while under a load climbing a long grade on the highway. It progressively got worse and would shut off when coming to a stop. It would crank up and run and I drove appx 30 miles home. I think it may be a sensor but I cant seem to find a ALDL port to scan for codes. If you have any idea or have ever had similar problems please let me know which sensor you replaced. Thanks so much for your time.

Jess

 

[joe_peters]

When was the last time the fuel filter was changed?

Put a fuel pressure gauge on it and drive it under a load and see what happens.

 

[jesswilliams]

I will check the fuel psi soon when I get a gauge. Today It started fine but when you give it throttle, it was like it was running out of fuel and would stumble real bad then idle back up to normal idle rpm. Thanks so much for your time joe_peters.

Jess

 

[ehall]

If it has the original computer (which it should) then it won't have an ALDL port. It might not have any diagnostic port at all, depending on which computer is in there.

In fact the kind of computer will dictate the kind of sensors and everything else. Do you know what it has?

 

[jesswilliams]

The computer is supposed to be a mopar performance ecm. It has an emissions exempt tag on it. I did check the fuel psi today...it was 32psi at idle and 42 with the vac line off of the regulator. It seems to idle fine but if you open the throttle it just bogs and will pop sometimes. I need to find the diagnostic port so I can get a scanner on it. How many pins will it have or what will it look like. It may be under the dash and I just cant see it...we added a new collins bros ac unit which makes it hard to look under the dash. I need to take the seats out so I can lay down and look under the dash. This is the only thing bad about a conversion unless you do it yourself. Thanks for all your time...I hope someone can lead me in the right direction.