Will My S1 Ecu Fit A S2 90 Spec G Plates That Im Thinking Of Buying,only Reason Is My S1 Ecu Has Been Chipped By Msd

 

yes, you need to swap the black fuel ECU for an S1 blue sticker item as well though.

 

Yup as above it will be fine although the knock sensor will not work (if it has one? early S2's didnt but its a G plate so it should!).
You dont have to swap the fuelling ECU, i'm runing a S1 ECU wiht my S2 FUelling ECU no probs, and my brothers S1 has a 90spec Hearts and Diamonds ECU with his original S1 fueling ecu.
But a S1 fuelling ecu is better as it has no rev limiter
If you do use one you'll need to rewire your TPS or you will have no full throttle enrichment, or fuel cut on closed throttle. You'll need to run the earth from the TPS to PIN 6 of the fuelling ECU (iirc).

 

So If I Use My S1 Ecu On A S2 With Tps It Will Need Earthing Out Or Only If I Use S1 Fuel Ecu Aswell?

 

only if you use the fuelling ECU from a S1, if you stick with your S2 Fuelling ECU you will be fine!

 

Thanks For That Mate