4.0 motor swap question

[oldskewl]

I have a '92 xj w/ 4.0 auto w/ np242 thats pretty rusty. Looking 2 buy a '90 w/ a blown 4.0. Would it be 2 much of a hassel 2 swap the good 4.0 out of my '92 into the '90. the '90 is rust free and very reasonably priced. if there is some differences what r they?

 

[joe_peters]

If you are keeping it Renix no problems.

If you want it OBDI you would want the entire wiring harness, sensors, and computers.

 

[Slip Kid]

If you're keeping the Renix electronics, which is easier, you'll need to swap every sensor from the 90 engine onto the 92. You should also use the 90's fuel injectors, and you will need its alternator too. If you are also going to use the new transmission, you will need to use the 90's flexplate, as the 90 crank sensor will not properly read the 92 flexplate, and it will not start. The Renix TPS needs to be adapted to fit on the HO throttle body. There is an adaptor available, i believe from Hesco, that does this. I made the adaptor myself, and there is probably pictures of it on here somewhere. To avoid the hassle of adapting the TPS, you could use the entire TB/intake manifold from the older engine. The Renix TB will not fit onto the HO intake. swapping the intake/TB/fuelrail and injectors would probably be easiest. Chances are there is a hole in the block already for the knock sensor, but you may have to tap it. good luck.

 

[oldskewl]

thanks for the input

 

[Slip Kid]

You could also swap the entire wire harness, and run the HO motor off the 92 OBDI computer

 

[Devnuts]

To swap out a renix motor for a HO do you need the dash harness too?
Is there a difference between the two besides electronics?

Sorry for the hijack​

 

[XJ&CHZ4ME]

I believe that you do due to the gauge cluster being electronic verses mechanical (speedo) from some of the early,or maybe all) Renixs

 

[joe_peters]

To swap out a renix motor for a HO do you need the dash harness too?
Is there a difference between the two besides electronics?

Sorry for the hijack​

Renix, OBDI, and OBDII. In my opinion the easiest switch is to make the engine work with the existing wiring and electronics, but if you decided to upgrade the wiring and electronics then get yourself good wiring diagrams for both systems and then you should be able to make an informed decision on what items will work or could be made to work.