Will this work? Using a S4 ignition wiring harness with a complete S5 long block engine and ECU.

More details here but I thought I spread the Q around a bit in case it got buried in a lesser known forum:
https://www.rx7club.com/forum/showthread.php?t=536779

TIA
Crispy

 

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Specifics:
I have a full *long block* (all manifolds, injectors, OMP etc) S5 motor that I'm dropping into an S4 chassis.
This is for an ITS race car so don't worry about accessories (PS,. A/C, emissions, etc.) To go with the engine I also have a 91 ECU and fuel side wiring harness and the AFM.

My question is what problems am I going to run into on the ignition side?

It looks to me like the distributor runs to the drivers (ignition)
side harness. This worries me. Any compatibility problems with the dash?
I plan on keeping the S4 alternator (I'm too cheap to buy an S5 one)

Help me.
TIA
Crispy.

 

The two plugs on the EMISSIONS harness will not mate with the FRONT harness plugs. You'd have to rearrange the wires so you'd have power to the injectors/afm/boost sensor/tps etc in the Emissions harness.

 

nn

 

Thanks. Yeah found that out yesterday when I went to plug in the (S4) front harness into the S5 N351 ECU

Ok now next question (if you have the time to answer). Will an S5 "front harness" plug into the existing fuse block I have in my S4? I can see a chain reaction starting where I keep replacing harnesses backwards through the car. I wouldn't be surprised if I end up yankingt he engine harness too. Grrrrr.

I'm thinking this exercise to swap in the S5 block and running gear is going to turn into a complete swap over of the entire electrcial system as well....what a PITA!

Crispy