Help with an electrical problem

[Eastwood]

I know they can be hard to diagnose if you can't see it, but maybe you can point me in the right direction. I have a stock 77' and I drove it to town the other day. I started it and it made a clunk then started. I parked it in the garage, then later that evening I tried to start it and it clunked, then nothing. I had no lights or anything. I had the battery checked, changed the starter relay,changed the cable from the relay to the starter and even talked the parts store into giving me another starter. After all that, it popped and atarted humming like the starter was hung. The positve battery cable got hot so I disconnected it. I got the lights, radio, and gauges working again. I thought maybe the ignition switch was shorted so I replaced that yesterday. Here's what I have now, if you hook the battery up it starts arcing and popping and then the cable gets hot, with the key off. When I turn the key nothing changes. Any suggestions?

 

[BroncoDawg]

Sounds like starter solenoid is fried and shorted so might start there.

 

[Eastwood]

I thought the same thing so I replaced it, the cable, and the starter. Still no change. Something is shorted I just don't know where else to look. Thanks for your suggestion.

 

[Viperwolf1]

Try disconnecting the alternator output cable. That's really the only other thing that can pull a lot of amps if it's bad.

 

[Eastwood]

Ok thanks. I'll check that when I get home today.

 

[Eastwood]

Well, I disconnected the alternator power wire and it made no difference. When I connected the battery the post was popping and you could smell sulphur. The positive post got hot in just about ten seconds. It's like it's hooked up backwards but it's not.

 

[Laxdad]

Eastwood, I had a very similar problem. What seemed to fix it was to route the negative cable from the battery to the frame and then run a ground strap from the block to the frame as well. I think my issue was my ground would never stay " clean" enough which created havoc by arcing and shorting my system out.

I tapped a 3/8" bolt straight into my frame in the pass wheel well.

Btw I have a 77 as well

 

[Viperwolf1]

Well, I disconnected the alternator power wire and it made no difference. When I connected the battery the post was popping and you could smell sulphur. The positive post got hot in just about ten seconds. It's like it's hooked up backwards but it's not.

Disconnect everything going to the positive side of the solenoid except the battery cable. If the draw is still there its a bad solenoid. If it's gone the problem is inside the truck.

 

[Eastwood]

I will check that ground out for sure, that old cable looks kind of sketchy. Yeah, viper I'm going to start isolating things today and see what happens.

 

[Eastwood]

Ok, I heard a popping noise and traced it to the coil. I guess a coil could short out, but I thought it would at least try to start. The parts store was closed and I got pulled off to do something else, so the saga continues for a while longer.

 

[nobodysfool]

just got a new solenoid for my 71 second time starting it it stuck.pull the starter cable off the solenoid to discharge it thats why the cable gets so hot.i also put a quik disconnect on the positive cable good thing.put the cable back on touch the positive cable to the batt should be good.somtime tap the solenoid with a wrench if it does it again toss it...

 

[Pa PITT]

.... OK I seem too also be the only GUY who has had this problem before...
YOU have the wrong solenoid on it..
...... I had a part store for 30 years and I saw this problem about 20 times.. Most of the times it'll blow the battery.
................................
.... Now my old 1980 Bronco I have fried battery about 3 times.. Get a different solenoid and thing were wright..
... Problem was that one of the no. I remember was SS581 It and the other solenoid had different grounded base.. Which ever you have on your Bronco you need the other style. In the back of the catalog it give this info.. OR IN the IPS. ILLUSTRATED PARTS MANUAL.

 

[Eastwood]

Hey guys, sorry I haven't posted in awhile. I've been working a lot of overtime and the bronco was put off. I did change the ignition coil and nothing changed. So I took the battery out of my truck and put it in there yesterday and here's what happens. If I turn the key to the on position the gauges come on and the headlights work. Then I try to start it and I hear one bump from the passenger side of the bronco. After that the lights won't come on and gauges stop working. The battery was hooked up for around a minute and the positive post was pretty hot. None of the other wires were hot. Ideas?

 

[Timmy390]

.... OK I seem too also be the only GUY who has had this problem before...
YOU have the wrong solenoid on it..
...... I had a part store for 30 years and I saw this problem about 20 times.. Most of the times it'll blow the battery.
................................
.... Now my old 1980 Bronco I have fried battery about 3 times.. Get a different solenoid and thing were wright..
... Problem was that one of the no. I remember was SS581 It and the other solenoid had different grounded base.. Which ever you have on your Bronco you need the other style. In the back of the catalog it give this info.. OR IN the IPS. ILLUSTRATED PARTS MANUAL.

PAPITT might be on to something.............

The solenoid is on the pass side and that bump is the juice hitting it. It's that or the starter is arcing.

The starter isn't in a bind is it?

Tim

 

[Eastwood]

Could be solenoid, But it's brand new. I know that doesn't mean anything but it's unlikely. It was doing the same thing with the original solenoid. I replaced the starter because my local parts store can't test them. They gave me another one because I bought the one that's on it about two years ago. I just don't know why after the bump I lose power to everything. The new starter has never tried to start.

 

[Timmy390]

The "BUMP" is the votage running to ground. It's the same and taking a wire feed welder and touching the copper tip to whatever you're welding on and pulling the trigger. The circuit closes and the welder goes bump and hums. You lose power to everything else because it's dumping to ground. The cables are hot becasue the circuit is cloesd and it's a defacto welder at that point. Just like with a welder, things start heating up and melting.

Something is jumping to ground or it sure sounds that way to me. The only places that have that much voltage are the battery and all connections, solenoid and all connections, and the starter and it's connections. You should have a ground cable going to the motor and the frame.

Check all the grounds and then look at the starter and verify it's A. hooked up correctly and B. isn't arcing.

Tim

 

[Larry B]

I think I would pull the starter and turn the key to the start position. If no short would check for froze up motor or broken tooth in the fly wheel.

 

[Eastwood]

I looked at the flywheel when I replaced the starter and it's good. No reason I can think of for a locked motor. Ok, how about this, today I was messing with it and I reconnected the battery. Then I had some family come by to help with another project. I left the battery connected for about an hour. When I went to check it out later, I touched the coil and it was red hot. Burn your hand hot. The ignition module was very warm also.

 

[Timmy390]

I left the battery connected for about an hour. When I went to check it out later, I touched the coil and it was red hot. Burn your hand hot. The ignition module was very warm also.

The coil shouldn't have power unless the key is on. Turning the key on sends 12v to the solenoid triggering the solenoid to send 12v to the coil.

I think the solenoid is fried or it's wired wrong.

Tim

 

[DirtDonk]

Ok, first off, it sounds like you have a defective positive battery cable.
Not that it would cause a short, but that it can't handle the loads put on it.
That would explain both the heat and the fact that everything dies after you hear the relay click.

It won't however, explain any of the other symptoms. We're just trying to eliminate it anyway, if there's more than one thing going on.
I suppose that if you have a short through the starter relay it could stop the power, as
Timmy390 was saying, but only a few other things can kill power to the rest of the truck. Those are:

1. The main positive battery cable. Just get a new one and be done with it. Cheap insurance. Might as well get a new negative too, while you're at it. Less than 15 bucks and you can at least eliminate them from the list.

2. The main negative cable, but you said you replaced that I think? Or was it just the starter cable?

3. The fusible link there at the relay that feed battery power to the rest of the truck.
They can fail partially, but usually once they're blown, nothing works after that.

The ignition coil can't do any of these things, so it sounds like you now have a trail spare.
The starter can cause the click, the hot wire, and a few other things, but it can't kill the power to the rest of the truck.

Another test though, is to disconnect the starter cable from the relay and try again. If it still does it, then you know it's not your starter causing excessive current to be drawn through the cable.
Disconnect the little Brown wire on the "I" terminal to the right of the relay, and that will eliminate any direct connection between the ignition coil and the starting system.
All ignition coils get hot when the engine is running or the key is left on. But the only way for that coil to have gotten hot would be if the key was on, the relay was bad and sending power up the Brown wire, or the ignition switch is failing.

Give those few ideas some time in the light of day and see what you can narrow down.
It's not uncommon any more to get a bad starter relay right out of the box. In fact, it's VERY common unfortunately.
So don't rule that out completely yet either.

Good luck.

Paul