Would a loose Alt Belt cause my fuel pump fuse to fry on my 930?

[seafood10]

So I was out driving today and could hear my belt squeaking so got home and parked it. About 15 mins. later I went to start it to move it into my garage and it would not start, thought
I had a hot start issue and then checked the fuses and the below pic is what I found.

I moved some shims out to tighten the belt, replaced the 25 amp fuse and went for a drive, no squeak and it drove fine.

Just wondering if for some reason with the alternator not spinning fast enough it would somehow cause this issue.

Thanks for looking!

[PeteKz]

I don't think your belt had anything to do with it. Two problems spring to my mind:
1. Cheap plastic fuse. Those should not melt. Get the genuine ceramic ones.
2. High resistance connection to the fuse block. Clean the metal spring where the fuse contacts, then bend it towards the other metal spring to make sure it clamps the fuse firmly in place.

Long term solution: Get the Classic Retro fit replacement fuse blocks that use the plug-in fuses. There's another well-regarded supplier but I forget their name.

[wildcat077]

What Pete says ...
I installed a retro fit blade fuse block in my 89 many years ago as i didn't trust the original fuses anymore which were coming loose and were a possible short waiting to happen.
Lots of reading regarding the subject , most kits now also come with the updated headlight relays as well.

[brianlay]

Fuses get hot because the connections develop high resistance and the current causes heat to build up.
Yes, ceramic fuses have a much higher melting point than plastic ones, but the most important thing with any fuses is to keep the connections clean (free from oxidation). Modern fuses are less likely to develop contact oxidation.

Anything drawing high current can cause the alternator belt to squeak, if it's not tightened correctly.

I would check the current draw of the fuel pump to confirm if it's higher than normal. High current could indicate it's nearing end-of-life.

[seafood10]

Originally Posted by wildcat077

What Pete says ...
I installed a retro fit blade fuse block in my 89 many years ago as i didn't trust the original fuses anymore which were coming loose and were a possible short waiting to happen.
Lots of reading regarding the subject , most kits now also come with the updated headlight relays as well.

Thanks, I have looked at them before but may take a harder look now.

[seafood10]

Originally Posted by brianlay

Fuses get hot because the connections develop high resistance and the current causes heat to build up.
Yes, ceramic fuses have a much higher melting point than plastic ones, but the most important thing with any fuses is to keep the connections clean (free from oxidation). Modern fuses are less likely to develop contact oxidation.

Anything drawing high current can cause the alternator belt to squeak, if it's not tightened correctly.

I would check the current draw of the fuel pump to confirm if it's higher than normal. High current could indicate it's nearing end-of-life.

Appreciate the reply,l I am going to go through them with a brass brush and some Deoxit to ensure they are clean.

[spoke]

It looks like the fuse did not blow. The element is still intact. As others have said, oxidized connections of the fuse to the holder will create resistance. Power dissipation is I x I x R. If resistance (R) is high, there will be power dissipation and heat generated. Clean your fuses and fuse holders with fine sandpaper and spray with contact cleaner to remove debris.

[seafood10]

Originally Posted by spoke

It looks like the fuse did not blow. The element is still intact. As others have said, oxidized connections of the fuse to the holder will create resistance. Power dissipation is I x I x R. If resistance (R) is high, there will be power dissipation and heat generated. Clean your fuses and fuse holders with fine sandpaper and spray with contact cleaner to remove debris.

Appreciate it! I used a bras brush along with Deoxit and it appeared to clean it, I'll be doing more soon.
I noticed that the element was still intact as well which led me to believe that there was some corrosion and like you said resistance.
Everything seemed to work today but am going to focus my attention to the fuse block and check them all.

[PeteKz]

Originally Posted by seafood10

Appreciate it! I used a bras brush along with Deoxit and it appeared to clean it, I'll be doing more soon.
I noticed that the element was still intact as well which led me to believe that there was some corrosion and like you said resistance.
Everything seemed to work today but am going to focus my attention to the fuse block and check them all.

Definitely do that. Furthermore, preemptively replace all the fuses. Fuses get old too, due to many heat cycles, they develop small cracks, then fail more easily. Do this every 10 years or so.

[brianlay]

Still curious to know the current being drawn by the fuel pump

[GH85Carrera]

Originally Posted by PeteKz

Definitely do that. Furthermore, preemptively replace all the fuses. Fuses get old too, due to many heat cycles, they develop small cracks, then fail more easily. Do this every 10 years or so.

This!

If you look on Amazon, and search for ceramic bullet fuses, it will bring up several sets. Try and find one with copper contacts, and real ceramic cores. That is what your came with. The plastic replacements are junk.

And I replace all the fuses every 10 years of so, and I clean the contact part of the fuse holder as well. Then coat the fuse with anti corrosion electrical compound.

[917_Langheck]

Originally Posted by GH85Carrera

This!

If you look on Amazon, and search for ceramic bullet fuses, it will bring up several sets. Try and find one with copper contacts, and real ceramic cores. That is what your came with. The plastic replacements are junk.

Search term Flösser bullet fuse will get a result for a Texas supplier.