Hello. I actually own one of these trucks, I have a 2001 4.0 liter. But the ECM shouldn't shut down because of spark plug wires. Now I know the routing of these wires, and what two wires caught fire? Which cylinders were they for? Because I know on my truck the spark plug wires for cylinders 1-3 run in back on the Intake manifold and just above them is the wiring harness and the ECM is right there too. For a wire to catch fire like that is rare. It must have had an opening in the wire insulation and the spark was jumping to the engine block for quite a while. These trucks have what is called a Waste Spark system. So, the Coil pack has three coils, each coil delivers spark to two cylinders. Therefore, there is spark occurring on two wires at the same time. The spark leaves the coil, travels down the sparkplug wire, jumps the gap at the spark plug, then continues through the engine block, jumps the other spark plug gap, continues through the wire and back up to the coil where the extra energy is dissipated through the secondary coil windings. It's not a well-designed system at all. Spark plugs wear out twice as fast and coils go bad faster as well. So, I would be concerned with where the fire happened and if it melted or affected any other wires in the harness, especially behind the Intake manifold.
So, inspect the harness really well. If the wiring for the Crankshaft position sensor of Camshaft position sensor melted, it will not fire the fuel injectors.
If you have a scan tool also, I would see if you have communication with the ECM, just try to get any codes or look at live data. If it says no communication when you hook it up, then there's a wiring issue.
https://www.2carpros.com/articles/how-to-test-an-ignition-system
https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor
https://www.2carpros.com/articles/how-to-check-wiring
Dec 26, 2021 at 7:03 AM
