ECM Fuse keeps blowing

Hi,

The ECM fuse powers a few different things. First, all the fuel injectors receive power from it. Also, the crankshaft position sensor receives an ignition feed. Last, the ignition coil driver as well.

I attached the schematics below for the powertrain management circuits. I highlighted all the wires related to the fuse you mentioned. Before going crazy, check to make sure the pins where the fuse plugs in are in good condition, not bent, pushed in, or corroded. A poor connection creates heat which can cause the fuse to fail.

Next, look at the schematic. It indicates where the wires go. Check for a short or damage to any of the circuits powered by the fuse.

I suspect that we have a bad connection at some point causing heat to build up until the fuse fails. If it were a dead short, that would blow the fuse right away, so make sure to check all connectors as well as wiring conditions and for corrosion. Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-wiring

I'm sitting here thinking. Make sure the wiring at the crankshaft position sensor isn't rubbing the crank pulley. It's just a theory at this point.

Let me know what you find or if you have questions.

Take care,

Joe

See pics below. Note: The schematics were four pages long. I had to cut each pic in half to make them readable for you. I did overlap them so you can follow from one to the next.

Thanks for your reply. I'm going to check what you mentioned and reply what I find. thanks again

Also I don't think it has a crankshaft sensor.

Hi,

Let me know what size engine you have so I can better confirm exactly what we are dealing with. The wiring schematics are for a 5.0L V8.

Take care,

Joe

It has a 350, 5.7 L.

Well, truck is running fine now but not sure if what I found fixed the problem for sure. Part of wires in the wire harness were too close to exhaust manifold and a bare ware on part of the wire to the oil pressure sending unit repaired those issues. The truck doesn't blow ECM Fuse thanks again for info appreciate it.

Hi,

Thank you for the update, and you are very welcome. If there were wires which melted near the exhaust manifold, chances are that is where the problem was coming from

If anything changes, let me know if there is anything I can do to help.

Take care of yourself and feel free to come back anytime in the future.

Joe