4.0 Engine swap

JPTHING · Feb 8, 2007

Is it possible to swap a Renix 4.0 engine, into the spot where a 4.0 HO used to be? Can I use the intake, and exhaust from the HO on the Renix? Do all of the wires, and plugs for the HO work on the Renix?

redyj1 · Feb 8, 2007

your biggest problem is the motor uses a completly different wiring harness, and needs to be customly fabbed... its a bitch

junkyard jim · Feb 8, 2007

You can swap the intake (with a little custom work on the gasket) but there is no EGR pipe on the HO exhaust and the ports were changed slightly (intake raised on the HO head but the exhaust stayed the same)
Some people leave the intake and mod the throttle body to swap and run the injectors matching the EFI system. Renix ones run leaner than HO.

JPTHING · Feb 9, 2007

OK so I have the engine wiring harness, and the ECM. How far do I need to disconnect, to make the swap pretty simple? Is there some point where I can just plug in my harness for the ignition, use the ECM, Harness, and the Renix engine. I have the the wiring diagram, if any of the above is not possible, can I use the harness, ECM, and Renix engine, then splice some wires to get it up and going. At this point, this is pretty much a complete engine swap, which wouldn't be much different than putting this 4.0 in anything. BTW, I am replacing my wife's non running 211,XXX mi. 4.0 HO, with a (free) great running 130,xxx mi. Renix 4.0.

junkyard jim · Feb 9, 2007

Are you going to put the Renix EFI on the new motor? If so, just swap the intakes along with all the sensors and you're golden! Knock sensor and depending on the year of the HO, temp sensor are different. (crank sensor and flexplate are matched to the EFI system as well)

Avanteone at Auburn car repair has done the swap before. I helped my son do a Renix head into an HO Jeep.

NotMatt · Feb 9, 2007

AFAIK, the block and head are pretty much the same, why not swap the IM and all the electronics off the one you've got and put them onto the renix block/head? Much simpler in my mind that rewiring the whole thing to make it RENIX.

JPTHING · Feb 9, 2007

Does the HO Intake fit the Renix, and do all the sensors work on the Renix engine?

junkyard jim · Feb 9, 2007

You can fit the intake onto it (with minor work to ensure the ports seal)

Which efi are you planning to run? Take the whole underhood harness from the HO rig and you have pretty much everything you need for the swap.

JPTHING · Feb 9, 2007

Here are the details, '91 XJ bad engine, '88 XJ 4.0 I am using to swap into the '91. I am hopefully using the '91 Efi system, all the '91 sensors, flywheel, and CPS.