Are 4.6l SOHC and DOHC engine harness the same?

Engine swap 1991 mazda?

• im swapping my protege's engine out, im going 1.8 sohc to 1.8 dohc, i read somewhere about some type of variable valve timing called vics that the dohc mazdas have.........Do i need the dohc wiring harness for this? What will i need to pull off of the donor car? is this plug and play?

• Answer:

  Use the electronics off of the car that you are putting the engine into. You may need other parts (like the oil pan and pick up tube if using a RWD engine in a FWD car). This includes the MAF and throttle body. This means matching the distributor and injectors to the existing ECM. The injectors and harness should not be a problem unless you are going to the low resistance type injectors. I would use the injectors that match the ECM (but adapters can be found). Yes you could use newer electronics, but is is easier to use a newer engine with old electronics then an old engine with new electronics. Some of the newer 1.8 engines have an knock sensor, which does not have to be plugged in when using a ECM that does not have that input. But if the ECM requires a knock sensor then one has to be installed. If you happen to come across a source for a variable valve timing for a Mazda 1.8, let me know. I don't think Mazda ever put them into production. If they did then you would need the ECM too. (flying miata has more info on engine swaps that you might want to read)