4.0 xj into a 2.5 MJ both 89's

[rockwerks]

Its funny I have a low mile 89 xj with 4.0 aw4 and 242 that I can't sell but many wrangler guys want my 2.5 TBI out of my MJ..so Im wondering what to look out for in the swap?

I know the fuel pump is different, motor mounts, etc. but will I have to change over wiring harnesses, or should the MJ already have the same harness in place.

and what else am I missing?

[Eagle]

The '89 2.5L is a TBI Renix system, so there are some differences in the underhood harness -- you're only firing one injector rather than 6. Don't know how different, or if there is a connector where you can make the change. I'll be doing the same thing soon, except mine's an '88 so I plan to just unplug the C101 connector on the firewall and drop in the injection harness for the 4.0L. Unless yours is a very early '89, you won't have a C101 connector.

[CheapXJ]

Originally posted by Eagle
I'll be doing the same thing soon, except mine's an '88 so I plan to just unplug the C101 connector on the firewall and drop in the injection harness for the 4.0L.

That's possible? that'll actually work?!?

:confused:

Oh, Brian... I'm currently about halfway through this particular swap (just came in to take a drink break actually :D ) so I'll let ya know if I run into any weird problems.

[rockwerks]

KOOL! this truck cant be down long its what I haul my water in!:D

[rockwerks]

C101 connector on the firewall and drop in the injection harness for the 4.0L. Unless yours is a very early '89, you won't have a C101 connector.

HMMM..so where is this C101 connector my book dont show it.:rolleyes:

[CheapXJ]

C101 is right above the brake booster. it's a HUGE connector

[Eagle]

They eliminated the C101 connector in mid-year 1989. I had always thought it was for everything under the hood, but in a recent perusal of the 1988 factory wiring manual (for an unrelated issue) I saw that it is labelled as "Injection Connector"

My next step, when I finish the current project, will be to compare the 4-cyl and 6-cyl schematics for the dashboard side of the C101 to verify whether or not I can just swap it from C101 out to the engine.

[CheapXJ]

Originally posted by Eagle
They eliminated the C101 connector in mid-year 1989. I had always thought it was for everything under the hood, but in a recent perusal of the 1988 factory wiring manual (for an unrelated issue) I saw that it is labelled as "Injection Connector"

My next step, when I finish the current project, will be to compare the 4-cyl and 6-cyl schematics for the dashboard side of the C101 to verify whether or not I can just swap it from C101 out to the engine.

I can assure you that it's NOT for everything under the hood. in fact, it ONLY connects to the injectors, CPS, TPS, IAC, temp sensor, knock sensor and O2 sensor.