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#22 fuel pump fuse burned 1978

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Old 10-15-2010, 02:40 PM
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Erik N
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Default #22 fuel pump fuse burned 1978

Had this happen this morning at the tire installer- car wouldn't start. I have had issues with the #22 fuse (fuel pump) before, usually just a twist of the fuse would fix it. Today, the top tab of the fuse panel looks like it got pretty hot because it's discolored. Put in a new (blue) fuse and she started right up.

I replaced all the fuses, cleaned the contacts, and added dielectric grease to all a few months ago.

Fuel pump? The below-tank one doesn't sound any different than before.

Anyone else have this happen?
Old 10-15-2010, 03:36 PM
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Landseer
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Dielectric Grease? To keep the contacts from making contact?
Old 10-15-2010, 03:37 PM
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Hey Erik,

I had exactly the same problem a month back at the gas station.... I had to call CSAA but the guy who came knew classic cars and he tapped the tank with a rubber hammer to get the fuel pump started so I could get home and trouble shoot it.

The problem was NOT the fuel pump in the tank or the fuel pump Relay (XVIII) or the fuse (#22 - 25A), BUT was because of the loose fuse contact which weakens with age especially the high current (25A) fuses. The symptoms are that the torpedo fuse will turn or spin easily with your finger, so the FIX is the remove the fuse and carefully squeeze the contacts together so the fuse is tight and cannot spin under finger pressure.

Also as others have told me, replace all aluminum torpedo fuses with copper or brass fuses.

Hope that helps...
Old 10-15-2010, 05:49 PM
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docmirror
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As noted, remove the dielectric grease, it is an insulator not a conductor. Next, squeeze the pins of the fuse holder as noted, then clean them carefully with a small wire brush, or sandpaper. Use a new copper fuse and keep it clean. Mechanically cleaning the pins of the old fuse holder will help a lot. They do tend to corrode.
Old 10-15-2010, 06:09 PM
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Erik N
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Originally Posted by docmirror
dielectric grease, it is an insulator not a conductor.
WHAT?!?
I thought it was to potentiate the contacts. Isn't that why it is applied to bulb sockets and fuses? (insert sinking feeling here)
Old 10-15-2010, 06:47 PM
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Originally Posted by docmirror
As noted, remove the dielectric grease, it is an insulator not a conductor.
+1

It's great for boat trailer connectors that go under water.
Old 10-15-2010, 08:56 PM
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Erik N
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CRAP! Just wiki'ed "dielectric" and got this:

When a dielectric is placed in an electric field, electric charges do not flow through the material.

One step forward, two steps back.

Think the actual (ahem) "rehab" caused the heat?
Old 10-15-2010, 09:07 PM
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No prob, don't feel bad. A good cleaning will help tremendously. I used to have a tiny wire wheel that would go in a low speed drill that could clean these real well. It looked like it was for a dremel but I didn't use a dremel cause it's too fast.
Old 10-15-2010, 09:27 PM
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Its pretty much worth the time to pull the panel out.
Less complicated than it looks.
Careful, the little wire brushes will shed wires into the panel, so use them but be smart about it.
Gives you a chance to check behind it, too, for wires melting into each other.
Old 10-16-2010, 08:33 PM
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I had this problem also, in my '78. The fuse for the fuel pump was getting hot, and there was heat soaking at the contacts (see my earlier thread: https://rennlist.com/forums/928-foru...fuel-pump.html).
I did Sharkskin's CE panel R&R and it fixed my problem (see here http://members.rennlist.com/sharkski...04-Bzzzzzt.htm).



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