I rebuilt my engine, a 360, goes into a 1976 F350. Put everything the way it was back. Along the way of hooking everything back up, the ignition wire in line fuse blew. My mechanic said that I should buy a new in line fuse holder (modern version of this fuse) and place it in where this old in line fuse was. I did so, placed in a 30 amp fuse as he recommended and it blew, repeatedly put in 30 amp fuse till I ran out. What could/is wronge!!!????

 

I assume that its a fuseable link youre talking about. You have a wire pinched somewhere shorting out the vehicle, bout the only thing that can cause it.

 

Yes thats what I am talking about. OK so from your saying there is a pinched wire along the lines thats bunched up in the electical tape that runs to the voltage regulator. If I recall right, when I took things apart (old electical tape off) and things were dangling on their own, I hooked up the wire directly then with no fuse and lights lit up. Should i try this again with a fuse in the line and things dangling on their own and go from there see if it still blows or not???? If things work hook it all up again but loosly in electical tape and see if it turns over for me?? Do I also put in another 30 amp fuse or a smaller or larger one??

 

Im lost on most of that. Anywhere that draws off the main power of the vehicle, if it shorts before it gets the fuse box, it will burn out the fuse link. I gather your voltage reg. wires are in rough shape, a short there could cause the fuse link to burn out, yes. That is what caused me to replace mine, was the voltage reg. wires.

 

OK thanks I'll check it out and see if I need to replace that, I may do so just to be on the safe side, I hope it does work!!!

 

Just start looking for wires the might have gotten pinched between the engine and frame when putting it back in the truck. My case was when i had the alternator out and put it back in, the alternator was crushing one of the wires. I was 15 and in my infinite wisdom and haste totally over looked this, then could figure out why my whole truck was dead.

 

OK, well in my case my wires are where they need to be but tightly wrapped up in electical tape. I'll take them out of the tape and see if this helps. If it does then I would assume that would be the problem. I'll go to my local parts store too though to price out the wire set from the reg. to the seloniod. Do you remember what it cost you? I am also in Canada so the price will be a little bit more.

 

I grew up on a ranch, i hopped on the 4 wheeler and headed up to the junk pile with a pair of wire cutters. Cost me about 15 minutes.

 

Do you have a "short detector"? A little ghetto fabbed piece of equipment, comes in pretty handy, I have one made of a sealed beam and door buzzer.

Pull fuses out one by one until the detector goes off, and you're good to go! Pinched wire/stripped insulation/bare wire is pretty much the only cause of this

 

Do what now? this sounds interesting and useful

 

electrical problems are my specialty in the older cars and trucks they are hard to diagnose and easy to fix. we have done several older rides with painless universal harnesses and even do a few harness restorations a year in the shop. that said it kinda sounds like your replacing the fuseable link that goes to the alternator with a 30 amp fuse? if so you have too small of a fuse. you have to have a maxi fuse probally a 60 amp or better (10 amps more than the alt is rated for) im running a 3g swap on a 70 and its running a 250 amp stereo fuse. the main feed in to the fuse box needs at least a 50 amp maxi if its a stripped base model if its a a/c with extras it may need a bigger one with some wiring upgrades.

 

If you need to replace a fusible link, just replace it with a fusible link. Fusible links are very easy to get ahold of. A fusible link needs to be sized two AWG sizes smaller than the circuit it protects (e.g, use a 14-AWG link to protect 10-AWG wire). But first figure out what's actually making the link blow.

There's no such thing as an ignition fuse in these trucks. Can you describe exactly what wires you're working with?

 

fmc400- The wire I am dealing with as far as I know is the wire that allows all the power to go to everything, lights, dash etc. Anyways the wire goes from the power side of the starter solenoid down to a adapter type of "plug" and from there spilts into two wires, one goes to the voltage reg. (of the same color, yellow) and the other wire, turns into a red wire, and goes into a pug that continues onto the rest of the truck as far as I know.

stuck in the 70s- the fuseable link im replacing does not go to the alternator it goes to the voltage reg.

additional notes: today after work I took a look at it again and no wire are "tangled,pinched or caught" anywhere, and still have the same problem. so to put in a bigger fuse then a 30 may solve this problem??

 

there a a lot of things relying on that circut hypothedicaly speaking the heater pulls 20 amps the lights pull 20 amps the radio pulls 5 amps, tail , dash brake lights pull another 5 amps right there your at 50 amps.
your best bet is to just replace that fuesable link, but with some of the newer equipment we put in our older rides we need to up grade to a fuse or even a resettable breaker.
figure out what is running on that circuit add everything up and add 10% then use a maxi fuse were the useable link was. basically just power up the truck with everything off remove the fuse and see what works and what does not. it may be the main feed and nothing works if thats the case find out what amperage your alternator is say its a 50 amp you put in a 60 amp maxi if its a 35 amp a 40 or 50 will be fine.

basically your fuse is too small and the wrong type. the "small" blade type are quick acting and will not handle a "shock load" lights come on and they draw 28 amps to fire up and drop off to say 20 amps running. a maxi fuse is a larger fuse and slower to blow so a 30 amp will take 35 amps for a second or so before letting loose and opening the circuit. a breaker is my preferred on the alternator or voltage regulator because they will handle a larger load for a few seconds before heating up and opening the circuit. the breakers are great if your running a big stereo or winch were the alt has to work hard to keep up.
i hope that makes sense to you if you cant figure it out give me wire color codes your working with and truck specifics and i will dig out a wiring diagram and figure out your amp loads and help you find a solution.

 

OK - yes, that sounds like the main power feed to the truck.

The voltage regulator doesn't connect through a fusible link. It's lighter gauge, and unprotected.

Don't mess with fuses here. Use a fusible link. First understand where the short is coming from, then replace the fusible link.