HI just wondering if I could fit a later ecu unit into a 1991 xj600 pre diversion to resolve the starting issue

i swapped my fz600 engine for a 91 version and had to use the correct ecu.

it wouldn't start and there should was a very long (over 6month) fault finding escapade.
It was down to 1 wire wittch tested ok, but failed when electricity was used.

check your ecu number and google that, I may have one in my shed somewhere as I did the same thing.

Wasn't until i bypassed the loom was the error found