another engine swap question

[rollovercomancheguy]

alright i have a 1988 jeep comanche its 4.0 is blown its auto aw4 and i want to swap engines from a 1991 jeep cherokee that has the 4.0 ho and am wondering what all i have to switch regarding wires sensors an so forth but the 4.0 thats in it now has a cracked head and split block that is why I'm switching the whole thing over. Also can i use the ecu from my 88 for the 91 or swap ecus an id it a direct fit thanks guys you guys rock

[rollovercomancheguy]

ps if anyone lives near central pa an wants to stop in ill show you it thanks tony.

[Eagle]

Your question is unclear. The '88 is a Renix -- the '91 is a Chrysler. That refers to both the ignition and the injection. Mechanically, the engines are basically the same, but the heads are different, the throttle bodies are different, and (most importantly) the entire injection and ignition setups are different and not compatible. It's not as easy as swapping ECUs -- the entire engine room wiring harness is different, and the under-dash harness is different. The Renix ECU is under the dashboard, above the driver's right foot. The Chrysler ECU is in the engine compartment, at the left front between the airbox and the inner fender.

 

Also, the CPSs are different (to work with the different ECUs, so you also have to use the CPS and flywheel that matches the year of the ECU.

[cruiser54]

Easy. I've done a few. Keep all your wiring, sensors, manifolds, distributor, valve cover and flywheel/flexplate. Use an intake/exhaust gasket from an 88.

Be sure to remove the coolant galley plug on the 91 engine and install your CTS there BEFORE installing the engine.