Blowing the PCM/ASD fuse

SHELLY LEWIS WALL

MEMBER
1998 PLYMOUTH BREEZE
2.0L
4 CYL
FWD
AUTOMATIC
179,000 MILES

Replaced a bad alternator and went for a test drive with in about fifteen minutes going about fifty mph the car stalled. Tried to restart and it would not. Popped the hood and found that my number five PCM/ASD fuse had blown. Put a new one in two times to get back home. So now with the new fuse I can start the car rev it up, but if I put the pedal to the floor it immediately blows that fuse. I have kind of looked at wires to check for a short. Would it be a short or something else? I am not sure where to go from here. Before the alternator was changed the car was acting sluggish, but never blew the fuse.

Monday, July 10th, 2017 AT 1:12 PM

3 Replies

CARADIODOC

MECHANIC
34,206 POSTS

"but if I put the pedal to the floor it immediately blows that fuse"

Do you mean the accelerator pedal? I assume you mean with the engine running, that causes the fuse to blow. What about pushing that pedal to the floor with the engine off and the ignition switch on? In other words, is it an issue of the throttle linkage rubbing on something or is it related to when the engine rocks during hard acceleration?

The first place I would look is the two smaller nuts on the back of the alternator. One of those is fed right from the automatic shutdown, (ASD) relay. The next thing to look for is if a wiring harness fell down onto hot exhaust parts on the back of the engine, and melted, then shorted to ground.

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Monday, July 10th, 2017 AT 9:53 PM

SHELLY LEWIS WALL

MEMBER
2 POSTS

Just to update. We called the store and asked if it was possible that it was our new alternator we had just put in could be bad partially because this car has never blown a fuse until we put in the alternator. They said that anything is possible and we could bring it back to the store and get a replacement. Well that fixed the problem. Hopefully this will help someone else before they rewire everything and about rip the whole car apart. Good luck!

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Friday, July 14th, 2017 AT 11:00 PM

CARADIODOC

MECHANIC
34,206 POSTS

Thanks for the update. There's no arguing with success, but if this had happened to me, it would likely have had something to do with the way I had connected those two smaller wires. I like to know exactly what caused a problem like this so I know what to watch out for next time. To do that, I would have liked to put the first new alternator back on, then see if the problem occurred again. Whether it did or not, I still would have opted to use the second new one, just to be safe. Happy to hear you solved the problem.

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Friday, July 14th, 2017 AT 11:30 PM