what is happening

[fergys_super10]

ok my truck is a 1992 2wd 2.5l tbi with 4 in body lift. my truck broke down on the way to the store. i changed the ecm fuse and got about 20 ft from the starting point and the fuse blew again well it kept blowing so i replaced the ecm. it will start for 2 secs then the fuse blows. i have checked grounds and wires for shorts. does anyone know whats happening i need some help i think it might be the prom chip in the ecm but im a diesel mechanic so im lost with gas

[fergys_super10]

please help me ive been racking my brain for almost a month i need some serious help

[rlith]

Well, a blowing fuse indicates a short. So most likely you have something that rubbed through a wire or wire bundle... Break out your chilton and start following from the ecm out...Look for visual breaks and tears and open areas and use a multimeter. Things like this are tedious and time consuming at best. I do not envy you only because I've been there. The open area is rubbing against body or frame.

[fergys_super10]

Originally Posted by rlith

Well, a blowing fuse indicates a short. So most likely you have something that rubbed through a wire or wire bundle... Break out your chilton and start following from the ecm out...Look for visual breaks and tears and open areas and use a multimeter. Things like this are tedious and time consuming at best. I do not envy you only because I've been there. The open area is rubbing against body or frame.

thanks for the advice but ive checked the wires coming from the cab inside the cab and just all over for open wires showing or a short to ground

[rlith]

Originally Posted by fergys_super10

thanks for the advice but ive checked the wires coming from the cab inside the cab and just all over for open wires showing or a short to ground

Have you checked the engine harness? If so, then at this point you need to break out the multimeter

[kok328]

does the fuse blow only when it starts or can you blow the fuse just by turning the ignition key to "on" for a few minutes?