i 'll be glad to everyone who should tell me if a s5(89-91) engine can work properly with s4(87-88) ecu and harness?what is the difference between each managment?i've heard of different oil metering pump(electronic on s5).is this right?

 

I know that the s5 wiring harness incorporates the oil metering pump, if u got with a s4 harness u have to run premix or get a s4 mechanical oil M. pump.

 

you have to put all of the S4 parts on the car including front cover you have to use the S5 flywheel. its ALOT of work.....

 

is it possible for a mechanical omp(s4) to work on a s5 front cover?

if i have that fixed,will be any other problems?

 

no...

 

You can make it work if you weld an aluminum plate around the S4 pump that matches the flange for the S5 pump.