i got my engine installed everything is done started car it runs on one rotor, compression and spark is good im getting fuel cut to rear rotor


we tried a n/a s5 ecu and car runs fine.

all wiring resistance is within margin but jap ecu is cutting fuel on start

my mechanic had this problem once b4 on a swap to a 89 had same exact problem change ecu and problem is fixed

we tried with knock sensor and without has fps that came with engine

but my delima is i really cant afford a ecu at this time along with paying for install

would anyone know what is causing this fuel cut maybe a backwards wire between the 89 car and 91 jspec engine?

 

any input at all