warf90

I am also planning this swap with a 92 XJ complete donor. What about the fly wheel? Does that need to be changed? Will the H.O. crank sensor work with the Renix Flywheel?

Finally got to work on the temperature gauge problem. I found the purple wire open or broken in between the connector by the starter solenoid and the dash. I temporarly jumped a wire inbetween the sensor and the where the purple wire comes off the ignition switch and the guage functions properly. I think I am just going to run a new wire instead of trying to find the broken wire. OK now on to the fuel guage problem. Still have not figured out the cold running problem.

The O2 sensor is new. I replaced that during the engine installation. I thought the O2 came in to play more when the system goes into the closed loop. Maybe not though. I replaced the sensor for the guage and not the computer. It is the sensor that has the threaded rod on the tip and it was from the back of the head. I am going to pull the sending unit back out and check it. It sure sounds like you may be right about the float getting hung up in the full position.

I pulled the fuel pump/sending unit out of the tank that orginally went with the 4.0 L and installed into the tank in what was the 4cyl truck. The fuel pump/sending unit and instrument cluster were both in my other MJ before I junked it and it did work in the other truck. I guess I need to pull it bad out of the tank and make sure everything look ok with it.

I have not had to time to get back to the MJ, but some of the problems that I have is, I do not know what year the cluster came out of. I am guessing that it is an 88. The previous owner swapped it out. I did buy a sending unit for a guage for an 88. I assume thats what I got from the auto parts store. As far as the gas guage not working. I did install the 4 liter pump with the rest of the sending unit that goes with it. The coolant temperature sensor for the computer is there an plugged up. It is a different sensor than the one needed for the gauge. I am still not sure of the running problem. What is the difference between an 89 4 cyl dash harness and a 90 6 cyl dash harness? I did not see anything different. It looked to me that all the connections were the same. It may be the problem, I am not sure.

I swapped a 4.0 liter AW4 into what was a 4 cyl 5 speed MJ. I have a couple of issues that I need help with. The temperature gauge does not work at all. I am not sure what year the instrument cluster is from. I am guessing an 88 and I got the sending unit for an 88. The guage never moves. When I ground the wire out it still does not move. I had a spare gauage out of another 88 and installed it. Still no luck. The gas gauge does not work. It reads Full all time. Even when disconnect the wire under the bed the gauge does not move. When I ground it, it does not move either. But it is already reading past full. When I did the conversion, I left the dash wiring from the 4 cylinder in the truck. The 4 cylinder was a 89. The drivetrain was from a 90. They are both renix. The last problem I have is when it is cold it runs for about a 1 minute and then it wants to die. I have to give it gas to keep it running. When I drive it cold it stumbles from dead stop. It will only do that a couple times and then it is fine. When it warms up it runs good. THanks for the help.

thanks for the info Eagle, thats good news.

I am in the middle of swapping from a 2.5 liter manual 2wd to a 4.0/aw4 4wd. The 4.0 drive train came out of a 90 mj. This is going into a 89 mj. I am curious about the wiring harness for the dash and front lights. Is there a difference between the two. I know that I have to change the computer for the engine and that harness and add the auto computer and harness. Do I need to change the dash and front light harnesses?

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The 89 I am asking about is another MJ that I bought. It is a 4 cyl. The 90 I have is a 4 liter. Sorry for the confusion. The oxygen sensor makes sense, since it is running so rich. I do not want to put a ton of money into because I am junking the 90 and installing the drivetrain into the 89. The 90 I have is in pretty bad shape and the 89 I bought is in excellant shape. I just wanted to make sure the 4 cylinder was running good before I removed it and tried to sell it. The motor itself sounds and runs great. It only has 96,000 miles on it. Thanks for everyone's input.

I would think a clogged converter would make it lose power all the time. This thng runs great for about the first 10 minutes of driving. Although I could see the O2 sensor causing problems. When you drive it, it seems like it is starving for gas or the spark goes away. You step on the pedal and it just bogs and some times it will back fire through the throttle body. But after all that it idles perfect.

The other thing that I forgot to mention is the check engine light is on and it does smell like it is running rich when it is running. You are probaly right though, I should change the filter again and clean the tank better.

Yes also installed a new sock on the pump. What does not make sense is that it ran great for a week and then started doing this. I wish I had a fuel pressure gauge.

Sorry, yeah I also changed the fuel filter.