Electrical issue

[355shortbed]

I have 84 c10 stepside. Last summer I replaced the the engine w a 383 and due to it fouling plugS. I let sit over the winter. Last week I put néw plugs in it and fired it up to take it to another shop for tuning. I noticed the fusible link at the junction block on the firewall was smoking. So I turned it off and replaced it because the sheathing was already loose around the wire  before. I put a 30 amp inline fuse in it's place a reconnected the 2 wires back into the inline fuse. I started the motor and it poped the fuse so replaced it and started it, it ran for about 30 seconds then I cut the engine off and as soon as I hit the switch off it poped the fuse. I got to looking at the diagram for starting and charging systems and traced the wires to make sure none where burnt or freyed. But it didn't do this sinced I've owned it and since I've put new motor in what could have gone bad last week. Any ideas where to start at?? Or if the igniton swith may have a short in it.  

[Lt.Del]

Ensure your positive wires going to the starter and solenoid aren't touching anything.  This, in my opinion, is the hardest part of putting in a starter--ensuring the wires are installed at the right angle where they won't touch each other or ground out or hit the exhaust.

[1980c10]

Look for shorts and tighten everything up.

[VileZambonie]

What made you think you could just install a 30Amp fuse instead of a fusible link? Of course before you do it right you need to find the short. Look around the back of the valve cover, near the starter etc for a short to ground. search on here for fusible link

[355shortbed]

I've done it before with no problems on a 77 350 4wd  so figured it would work. I took the wires off of both posts on the starter nothing was touching where they could ground out.  I plan to go to parts store today and get fusible link and new wire. I am just going to re run wiring from junctin block to starter and alternator.

[Irish_Alley]

alt wire is connected right?

[bake74]

     Sure sounds like a dead short, look where vile said for any wire possibly grounding out, even if it doesn't look burnt doesn't mean it doesn't have a small hole in the insulation and grounding out your circuit.

[355shortbed]

Ok it's been a while since I posted back to this but I have replced the wiring from the junction block to both the alternator and the starter I left the 30 amp fuse in place to see if the new wiring worked and to no joy it poped the fuse again. I have looked for loose or broken grounds found none tested the main grounds they are fine. I replaced the ignition switch while doing the wireing. The fuse only pops when the engine is running, the wire from the alternator gets really hot thus over loading the fuse and popping it. So has to have somthing to do with the charging system right? I'm geting frustrated with this bad luck peace of a truck I don't want to give up on it . Has anyone had a problem like this? What should I do next what should I check and test. The painless wiring kit is 800 beans and out of the question classic parts has new engine wiring harness for 130 any opinions? I'm frustrated with this problem that arose all of the sudden   Somebody help please

[jaredts]

Your alternator puts out more than 30 amps, and more than your fuse can handle.  How much is the fusible link?

[griffo2k]

batteries/alternators will only put out the current needed for the load on the battery it seems as tho the starter is pulling too much current and blowing the fuse if there are no shorts. you can check for shorts with a volt/ohm meeter. if no shorts are found pull the starter and have it checked

[griffo2k]

oh i forgot if you are going to use a fuse you should use a slow blow fuse. a fusible link can maintain the higher current for a longer period compaired to a fuse

[Irish_Alley]

get the alt tested

[355shortbed]

I had the alternator checked it's good, the starter is a powermaster hi torque starter, I can take it to parts store and have then put it on the machine but all they will check is if the bendix comes out and turns, is it possible that the soliniod on the starter went bad causing this problem? i dnt thnk a slow blow fuse would help much not as hot as the fuse holder is geting I melted a piece of skin checking it yesterday it get hot with in 10 seconds

[griffo2k]

they can check the starter to see how much current it is pulling

[greg1984GMC]

If I am reading this correctly,  The fuse blows after the truck is running?  If the truck
is started and running and then the fuse blows--I don't think it's the starter.  The starter
draws it's power directly from the battery by way of the starter solenoid.  On my truck,
the fuseable link protects the interior wiring and accessories. Does the fuse blow or wire
heat up with the ignition on and the motor not running?   If it does then it's an accessory
issue.  If not, you need to isolate those circuits that are run only.  Do you have an aftermarket
ignition system like MSD?  Perhaps you have an ignition box or coil that is drawing way too much.

if the fuse blows during the engine start process, You might try disconnecting your ignition from
the system and then crank the motor to see if the fuse still blows.