What problems 92 harness > 94 Engine come up?

[s13loverdrift1]

Well I have a question now since I am going to be buying the motor next week once the mounts come in I was wondering if I should go with a 94 engine or if I should go with a 90-93 engine. I have I think 92 harness and I know the ECU can work because they are proven to be compatible. Also is there any true benefits to the siamese ports compared to the oval ports of the 94? The main reasons I want to go with 94 is so that I don't have to change the guides but if there is like a true benefit with going with 90-93 engine then I will most likely choose the 93 motor if it actually has benefits with just going and getting some timing chain guides. If anyone could name any other differences that would affect my decision that would be great. I heard something about the CAS not being compatible on the earlier harness. What would you have to do to make it work? I dont have the earlier FSM to compare the two thanks.

[gs14racer]

yes you can go back and forth, i just did that today on a friends car started with a 91, then to a 94 and back to a 91.

[s13loverdrift1]

So there are no differences between the wiring for the two? thats great to hear thank you

[SSDwellah]

I know your post is from over a month ago, so you have probably figured this out already. I am working from memory here so take this with a big grain of salt.

• The crank angle sensor (CAS) is different between -93 models and 94+ models. I think the connectors are different too. They have the same number of pins though, just different manufacturers (Mitsubishi vs Hitachi, just like there are diff brand distributors on some year Nissans and diff alternators, etc...).
• I think the injector connectors are different (but supposedly the subharness connector that connects the main EFI harness to the injector subharness is the same and has the same pinouts so you can swap them. I never had to confirm this.)
• I think the lower subharness connector might be different (the one that goes to alternator and trans), but I am really fuzzy and uncertain about this one.
• Depending on if one engine has TCS and one doesn't, you may have extra/missing/different connectors around the throttle body. Not 100% on this one either since mine did not have TCS

Good luck and post discrepancies if you find them.

[elwesso]

From all the guys that put 94 engines into 90-93 Qs, the only issues come up with the CAS.. Everything else is the same..