I have a 1999 Chevy express van with a 5.7L. It is blowing the ecm1 fuse. The ecm was bad, shorted out by too much volts the manufacturer said. Got another one and found the ecm1 fuse blown. Ecm is disconnected and blows as soon as the key is turned on. Narrowed it down to the injector harness. If I unplug harness it will not blow, plug it in and blows immediately. Plug in looks good no burned plugs and went back to harness as much as possible and all look good. Injectors were changed several years ago with a Delco set. Trying to decide whether to pull the plenum to check injectors or maybe if someone ran across this problem with a wire in the harness that maybe a common problem. Thanks in advance for your help.

 

update: pulled the plenum and injector assembly. Found a nick in the wire on #6 injector and it was touching blowing the ecm1 fuse. Hope this can help someone else in the future.