Ok, so this might be a dumb question. I tried seaching but good results failed to show. Can a S4 TII wiring harness be used with S5 TII engine and ecu? Is there any diffrences?

The only thing that I can think of that might be a problem is the metering pump. S4 is mechanical and S5 is electrical.

 

Let me see if I can get this straight you want to use a S4 TII wiring harness on a S5 TII block and an S5 TII ECU? That combination is not possible. Just for starters the plugs on the ECU were different from S4 to S5. Then you have all the other variables different injector impedance, OMP (electrical), AFM, etc.

- Dana

 

The S4 harness can not be used with a S5 ECU without major modifications