hey, my friend swap a b20 into his 90 hatch and wanted to convert to obd1. when he turn the key the ecu fuse blows. it only thing is that, it only blows when it obd1, also his fuel pump doesn't come on. we've check the jumper with another jumper and theres nothing wrong with it, also he has changed the ecu. i've searched and didn't find anyone with the same problem can anyone help me?

 

There has to be a bad ground somewhere.

 

try looking at every wire after the harness. maybe something is cut a little and hitting sumthing. or since u guys did a motor swap too... look for stranded wires.

 

alright but why is it that when he goes back to obdo it doesn't blow the ecu fuse and his fuel pump works