73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Electrical => Topic started by: 355shortbed on July 12, 2011, 09:37:07 pm
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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.
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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.
(http://www.delbridge.net/solenoid.jpg)
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Look for shorts and tighten everything up.
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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
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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.
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alt wire is connected right?
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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.
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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
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Your alternator puts out more than 30 amps, and more than your fuse can handle. How much is the fusible link?
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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
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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
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get the alt tested
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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
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they can check the starter to see how much current it is pulling
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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.
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Yes the fuse only blows when the engine is running after it is started, this is the3rd ditributor in the truck it is a MSD street fire H.E.I distributor we tested voltage at the fuse Monday and after the engine started the voltage at the fuse was at 13 volts then jumped up to 15 volts. Could a bad coil cause this problem?
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it should jump to around 15 volts the alternator should be regulated at 14.8 volts you should be more concerned about current. current takes the path with the least resistance. so you need to check for shorts to ground or a failing component on all the run side of the ignition switch like Greg says.
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The starter is not your problem. Go back to my last post and find your problem. You either have a chaffed wire or pinched wire in the bellhousing or something grounding that circuit. A Fuse is not going to work. Replace it with a fusible link once you find where it's shorted. It should be fairly easy since it's such a short lead from the junction block.
http://forum.73-87chevytrucks.com/smforum/index.php?topic=11972.0
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sorry to bring this topic back up but the other day i found somthing rather odd. i was tinkering with the wiring, ihad charged my battery up the night before. i unplugged the charging wire on the back of the alternator and started the engine up and let it run for a bit. after 5 minutes i took it up the road and noticed the engine running better than it had since i had installed the engine and it started fouling spark plugs every week. my point being is before unhooking the charging wire from alternator my plugs where all black and sooty and becoming fouled by too much fuel, and after unhooking that wire and driving the truck around the plugs have cleaned up to a nice chocolate color and the motor has come back to life and is driving great, the battery is not getting charged by the alt. but as long as it is above 12 volts the plugs stay where they need to be. Why?
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that really is weird.
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My best guess;
Check the voltage to your electric choke with and without the alt hooked up with the engine running. My guess is that some how you're losing voltage to your choke not allowing it to open completely. If the voltage increases to your choke with the alt disconnected that is the issue.
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Is the B+ stud on the alternator loose? Sounds like either the B+ is touching the case or it's time to replace the alternator.
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Well I just got a new alternator Saturday and I ordered a new engine wiring harness from classic parts. Hopefully it will work out . Wat I dnt understand is why it ran so poorly for about a year fouling plug after plug and all I changed in the equation was unhooking that wire and runs like it should , pretty odd. Guess it got tired of siting in the yard lol