You need the donor car with a 3.0 so you can swap all harnesses from one car to another. And if you use a manual transmission, you have to trick the ECM into seeing a TCM. And then, if it’s a VDC model, you have the communication network that goes between the ECM, the TCM, and the VDCCM. If it’s from an LL Bean, then you shouldn’t worry too much about the communication problem. You will need the ABS module from the 6 cylinder to match what the ECM will require. Additionally, since there were definitions built in for some six-cylinder computers, you could delete the transmission codes from the display. This has been the main problem is the check engine light comes on with the transmission codes because the automatic is not there. If there aren’t any definitions built for your 6 cylinder computer you find then you will post on the ROM Raider forum and see how to create definitions for it.
Air conditioner compressors for 6 cylinders are different from 4 cylinders. The 6-cylinder AC compressor has a speed sensor at the rear of the compressor. Alternators are different for six cylinders vs. 4 cylinders. The computer adjusts the alternator to six cylinders. You will also need the front springs from a 6 cylinder car due to the weight of the engine. You need the 6 cylinder radiator. You will need the instrument cluster from cylinder 6 because it is wired differently than four. This is where the complete car harness comes into play so that everything fits in just right.
You’ll need a clutch assembly for a turbo engine so it can handle the torquey power of the six. And if I remember correctly, the flywheel will clear the reluctor ring for the crankshaft sensor. The camshaft sensor on the six cylinders is at the rear of the crankshaft.
The six cylinders will be mated to the manual transmission.
It’s a chore to do this. You will remove the interior of both cars to remove the harnesses.
It might be easier to just find a 6 cylinder car that is in really good condition and swap out your manual components and then rewrite the ROM on the 6 cylinder computer.
