pineapple_tree

As i’m planning out my build, I am obviously swapping in the 4.0, or actually a 4.6. Regardless, the wiring harness needs to be either changed or modified.

So, the way I see it, I have 2 options.

My first option is to pull a wiring harness from an OBD1 4.0. I don’t mind doing that, but I think the engine harness is connected to the harness under the dash. I would imagine they are able to be separated, but I don’t know.

My second option would be to modify the original harness. I can get a PCM for a 4.0, and add pins for the 2 extra fuel injectors, but I’m unsure if items like the TPS, IAC, MAP, CKP and pickup connectors are the same, and also connectors for the radiator fan and connectors for the A/C, if I choose to have A/C

What I'm trying to say is, in all reality, what’s easier? To pull a junkyard harness, or to add or modify connectors and add pins?

Jim Malcolm

If you're intending to run a stroker and want to be able to actually tune it versus just bumping up fuel pressure and messing with the MAP signal, you'll want the late-95 or 96 setup with the OBD-II computer. OBD-II but without the CAN dash. 95-96 only with the 3 connectors for the ECM versus the 91-early 95 with just 1 big connector. The connectors on the sensors change in tandem with this change, but the resistances/range/voltage/etc are the same, so you can "just" wire in the proper connectors. If you have the 3 connectors to the ECM already, I'd look into just adding the pins, but otherwise, ...

pineapple_tree

Well, I was thinking about swapping over to OBD2. My 95 is OBD1, obviously, and it has the one gigantic connector with everything included in it. I feel like if I do that swap, I might need the entire wiring harness, because I’m not sure if I can “split” the original harness into 3 sections like the OBD2 XJ’s have. And if I want to go the non-can bus route, that’s going to be a task in of itself because most XJ’s I see listed anywhere are either up to 95 or after 97. I very rarely see those listed, and if I wanted to go the route of having a donor XJ, then finding a 96 that’s a turd is slim.

That’s why I’m starting to think that something like an LS swap is more feasible, because in order to swap in a 4.0, you need to change just about everything in the engine bay, including the radiator and support brackets, and I think the hood latches have to be changed too, along with the cross member and having the right harness as well.

I dunno. I’ll weigh my options and see what I want to do, and see what’s easier and cheaper maybe.