Novice mechanic needs finger pointing.

[madRABIES93]

I recently acquired an 89 Cherokee with a 4.0 that I'd like to swap into my 86 Comanche. 

 

They're both odb1.

 

I'd like to do an odb2 swap if possible. 

 

Do I need an odb2 engine or can I put an odb1 engine with an odb2 wiring harness? 

 

If the thread exists for this info please point me in the right direction. 

 

I don't have any specifics on my Comanche at this time.

[ghetdjc320]

OBD1 was used in 1991-1995 XJ’s and 91-92 MJs. The 90’ and earlier 4.0 has a renix efi system. I believe there are some difficulties swapping in a 4.0 in an 86 MJ due to motor mounts among other things. I am sure others can chime in. 
 

In regards to obd2, once you get the engine physically installed you can run it with just about anything if your up for the wiring and requisite sensors. If you need specific info let us know. It has been done many times here. 

[89 MJ]

If you want to swap a 4.0 into an 86, you will also have to massage the firewall. 
Personally, I would do an aftermarket fuel injection (Megasquirt) and an HEI distributor/MSD ignition if I were doing that swap. 

[87MJTIM]

An 89 XJ would have the Renix engine controls, unless a PO swapped in a HO engine from a 91-95 XJ. The Renix is a pre-obd system. (See Nickintime REM scan tool.)

 

You didn’t say what the 86 has in it: 2.5 or 2.8. To swap to a 4.0, you want all the engine wiring and the ECU (under the dash, above right foot). 
 

As 89 said, the 86s weren’t designed to fit the longer 4.0s. The firewall will need to be pounded with a hammer to fit in the 4.0. 
 

See the DIY section for info on doing the swap. 

[Pete M]

what are the end goals for the truck?

[madRABIES93]

On 9/6/2021 at 12:09 PM, Pete M said:

what are the end goals for the truck?

I don't really have any particular goals. 

Just kind of doing what I can with what I have. Eventually I want it to just look and sound cool. 

It's my first major project vehicle. 

[Pete M]

8 hours ago, madRABIES93 said:

I don't really have any particular goals. 

Just kind of doing what I can with what I have. Eventually I want it to just look and sound cool. 

It's my first major project vehicle. 

 

 

which engine do you have now?  does the truck run?  4wd? 

[dasbulliwagen]

An OBD2 swap would require a complete harness from a 96 and newer XJ, including under the dashboard, which might involve different intake manifold and different sensors. You might consider selling the 89 and buying a complete 96-01 XJ and then youll have every single part youll need. If you get a 97 and up, you can swap the entire newer dashboard and interior as a bonus. Trying to piece it together from three different models is going to be a pain. Though I have to say too, theres nothing wrong with keeping the 89 Renix setup. Just read and follow Cruisers tips for the renix system and it will be fine. 

[ghetdjc320]

I haven’t seen the OP reply yet but just to confirm, you can use a 96 XJ obd2 ecu and simply splice in a 91-95 HO engine harness. Not too terribly difficult to make that setup a stand-alone efi system. That way no canbus gauges are needed.