- Joined
- Oct 17, 2011
- Messages
- 755
- Reaction score
- 12
- Points
- 18
- Location
- New Joisey
- Vehicle Year
- 1987
- Make / Model
- Ford
- Engine Size
- 2.9L
- Transmission
- Manual
Last night my 2002 Explorer died on the highway.
It has a 4.6L V8.
I found it had blown Fuse 38 in the under hood fuse box which is listed as "Coil On Plug"
I replace the fuse, vehicle started and I managed to get a couple miles with engine seeming to run fine before the fuse blew again. After that fuse pretty much blew with seconds of starting the engine.
It didn't appear to blow when just turning on the ignition, but I did make the mistake once of having the ignition on when I was plugging in a new fuse. In that instance I got a spark and fuse blew immediately.
Is there any most common problem that could cause this fuse to blow?
The electrical diagram shows this fuse as only feeding the 8 ignition coils and two "ignition transformer capacitors".
Other side of the ignition coils is the PCM.
Based on the diagram I am thinking one of a few causes.
1. An ignition coil has shorted so when engine runs it draws unusually high current. Not sure how probable this is, they all were replaced 6 months ago.
2. One of the two capacitors has gone bad. I think one was already disconnected. Not sure what harm that causes other than electrical noise. Couldn't find where to connect.
3. The PCM has a problem and is not just pulsing the ignition coil but holding it on resulting in too much current. I tend to think because it started after the first fuse replacement and ran without issues for about 5 minutes that this seems unlikely, but don't know.
4. The wire from the fuse to the ignition coils and capacitors has a short someplace.
5. One of the wires between an ignition coil and the PCM is shorted someplace.
Any suggestions appreciated. Thanks
It has a 4.6L V8.
I found it had blown Fuse 38 in the under hood fuse box which is listed as "Coil On Plug"
I replace the fuse, vehicle started and I managed to get a couple miles with engine seeming to run fine before the fuse blew again. After that fuse pretty much blew with seconds of starting the engine.
It didn't appear to blow when just turning on the ignition, but I did make the mistake once of having the ignition on when I was plugging in a new fuse. In that instance I got a spark and fuse blew immediately.
Is there any most common problem that could cause this fuse to blow?
The electrical diagram shows this fuse as only feeding the 8 ignition coils and two "ignition transformer capacitors".
Other side of the ignition coils is the PCM.
Based on the diagram I am thinking one of a few causes.
1. An ignition coil has shorted so when engine runs it draws unusually high current. Not sure how probable this is, they all were replaced 6 months ago.
2. One of the two capacitors has gone bad. I think one was already disconnected. Not sure what harm that causes other than electrical noise. Couldn't find where to connect.
3. The PCM has a problem and is not just pulsing the ignition coil but holding it on resulting in too much current. I tend to think because it started after the first fuse replacement and ran without issues for about 5 minutes that this seems unlikely, but don't know.
4. The wire from the fuse to the ignition coils and capacitors has a short someplace.
5. One of the wires between an ignition coil and the PCM is shorted someplace.
Any suggestions appreciated. Thanks