Oldsmobile/Buick Repair: 89 olds ciera ecm fuse blows, olds ciera, ciera

Question
The ecm fuse blows on  my sons 89 olds ciera,2.5 engine.started
last month(blew once),then friday it blew 5 fuses at the ecm, i then had it towed to my garage. The next day started woking ok.Next day it blew
once. checked wires,nothing strange found. note: when it blew(the 5 times), i was able to unplug the injector but it still blew.Also , it blows when the key is turned to the on position, with me ingaging the starter.
any help will be apriciated.
earl

Answer
Hi Earl,
In the 89/90 period, there is a little difference in the wire diagrams, that depending on which part you follow, that fuse could be feeding a cooling fan delay relay. See if you have a relay marked fan delay, and remove the relay. It might have just enough resistance to blow the fuse sometimes.

On a different schematic, the ignition module is also powered by the ECM fuse.

There is also the remote possibility a wire is rubbed through and occasionally shorts to ground. That would be hard to find without tracing all the pink/black wires.

Van