Truck Died Instantly - Electrical Smoke/Smell

[harrydunn]

I keep my 72 in an off-site shed of mine on high-quality battery tenders for the last 11 years without any issues every. Yesterday, I popped the battery tender off of it, cranked it up and it started just like it always does. I pulled it outstide and let it run while I closed up the shop. It died instantly. No sputtering, just died like you turned the key off which means electrical to me. I raised the hood and instantly saw smoke coming from the battery area and that distinctive electrical smoke smell.

Curious where you think I should start. I have a couple of theories. Either a) my tender overcharged my battery or b) my alternator started overcharging my battery once I started the truck.

Stats: Battery voltage checked at 12.53. Battery is 2.5 years old.

I think my battery is fine--I'm guessing I blew the fusible link on the fender that comes off of the battery and that is what was smoking.

Would you replace fusible link, voltage regulator and alternator? All are at least 11 years old as they have not been changed since I got the truck.

Thank you for your expertise!

--Mark

[Stocker]

Sounds exactly like what my truck did a few years ago. I didn't realize it at the time, but I believe the alternator was overcharging. I know it was overcharging later on when we were trying to fix it.

I think you're on the right track -- replace the fusible link, get an internally regulated alternator, throw away the old voltage regulator, and beef up some of the wiring.

Only way I got mine fixed was with a ton of advice from great board members here. Gonna give you a link to my lengthy post -- the answers are in there if you can sift through some of my frustrated ramblings. Good luck!

http://67-72chevytrucks.com/vboard/s...d.php?t=772236

[harrydunn]

Ah interesting. So, no need for voltage regualtor if I get the interally-regulated alternator?

[Stocker]

Originally Posted by harrydunn

Ah interesting. So, no need for voltage regualtor if I get the interally-regulated alternator?

Correct. The link I posted tells how to eliminate it. IIRC, a couple wires get soldered together and a couple others are removed.

[harrydunn]

Well, here is what I found. The length of wire in the 1st photo that has been melted and literally pulled apart--is this the fusbile link? I believe it is. This would have been what was smoking I do believe as it still has an electrical fire stink to it. The red section of wiring runs up along the radiator support. Also, looks like that voltage regulator is decades old. So, my thoughts are, for now, put a new voltage regulator in (may convert the alternator to internal later) and replace that section of wiring that fell apart. If that is the fusible link, do I solder it back inline and shrink wrap or just a butt connector and shrink wrap? I can do either. Do you know what gauge fusible link to purchase?

Thanks!

[HO455]

I would do some troubleshooting before replacing any parts. The fuseable link will blow anytime there is an over current condition. You could have a grounded hot lead between the battery and the fuse box or farther down the circuit on an unfused circuit. Maybe rodent instigated.
You should be able to have the alternator and regulator test by a competent auto repair shop. The local chain auto parts store may or may not be able to test an externally regulated alternator.

My Burban's factory charging system went into overcharge and the result was it tried to cook the battery. A hot battery acid smell was the symptom I had with no damage to the fuseable link.
This link is to my repair thread scroll to post 467 where I start my conversion to a late model alternator. There is some information on fuseable links a couple posts down.

https://67-72chevytrucks.com/vboard/...698377&page=19

Good luck and post your findings so we all can learn more.

[Stocker]

Yessir, that is the fusible link. It should be 16 gauge. I connected my new one with a butt connector, then made a spare to keep in the glove box -- just in case. Hopefully that is your only problem. Keep a close eye on your voltage and if it shoots up (mine went over 18v) then you have other issues. I burned up more wiring than just the fusible link.

As to replacing your voltage regulator -- before I bit the bullet and converted to an internally regulated alternator, we bought three new regulators and none of them worked. They were not adjustable, and finally the mechanic put the original back on and tweaked it so it would work -- for a little while. YMMV

[Stocker]

Just found this, maybe it will help.... https://www.whiteproducts.com/fusible-faqs.shtml

Typically, a given harness segment is protected by fusible link that is four gauge numbers smaller. A 14-gauge wire would be protected by an 18-gauge fusible link. A 6-gauge wire would be protected by a 10-gauge link, and so on. Odd number wire gauge sizes like 19, 15, 13 and 11 are counted when sizing a link. The length of a fusible link should not exceed 9".


EDIT: HO455, glad to see you on here! You, Andy, VetteVet and others saved my bacon when I had my problems. Always nice to hear from experts!

[harrydunn]

Originally Posted by Stocker

Just found this, maybe it will help.... https://www.whiteproducts.com/fusible-faqs.shtml

Typically, a given harness segment is protected by fusible link that is four gauge numbers smaller. A 14-gauge wire would be protected by an 18-gauge fusible link. A 6-gauge wire would be protected by a 10-gauge link, and so on. Odd number wire gauge sizes like 19, 15, 13 and 11 are counted when sizing a link. The length of a fusible link should not exceed 9".

I pulled out my .pdf manual and it does look to indicate a 16 gauge fusible link so that's what I'm picking up tomorrow at NAPA. Hopefully that at least lets me start it up and drive it the two miles home so I can start digging in.

[harrydunn]

Yah, I thought about the rodent possibility too although I have not found any indications of that yet. Main thing is to get it the two miles from my shed to my actual home garage so I can work on it much easier. This would be a good excuse to upgrade my winch on my trailer to haul the old girl up there and tow her home!

[slikside]

I agree that the truck just dying sounds like a fusible link issue, but in pic 1, isn't the fusible link that black bulbous (where the fuse is) mass with the short wire going to the fuse block? That melted red wire is coming from the alternator via the voltage regulator, isn't it?

[Stocker]

Originally Posted by slikside

I agree that the truck just dying sounds like a fusible link issue, but in pic 1, isn't the fusible link that black bulbous (where the fuse is) mass with the short wire going to the fuse block? That melted red wire is coming from the alternator via the voltage regulator, isn't it?

I believe you are describing the fuse holder containing the short 4A fuse for the ammeter. There will be another one near the opposite end of the core support (driver's side of truck). Without both fuses, the ammeter won't work.

[harrydunn]

Originally Posted by slikside

I agree that the truck just dying sounds like a fusible link issue, but in pic 1, isn't the fusible link that black bulbous (where the fuse is) mass with the short wire going to the fuse block? That melted red wire is coming from the alternator via the voltage regulator, isn't it?

Slikside, are you referring to the area in the red circle? Someone correct me if I'm wrong, but I believe the area I've circled in yellow is the fusible link that comes from the regulator/alternator. Also, is the hard black tube on the fusible link just a connector between the two gauges of wire? I've noticed that style is hard to find. My plan is to cut the thick gauge red wire coming across the radiator support just on the other side of that connector and solder in the new fusible link.

Is that correct? Shown in green.

[Stocker]

Correct on all counts. The item circled in red contains the 4A fuse for the ammeter. You can pull it apart to verify. The solid section at the end of the fusible link contains the splice point, as you said. Cut the red wire where shown. Rather than hard soldering the fusible link to that red wire, consider a butt splice so you can make up a spare. That makes it much easier to replace if it blows again.

[harrydunn]

Originally Posted by Stocker

Correct on all counts. The item circled in red contains the 4A fuse for the ammeter. You can pull it apart to verify. The solid section at the end of the fusible link contains the splice point, as you said. Cut the red wire where shown. Rather than hard soldering the fusible link to that red wire, consider a butt splice so you can make up a spare. That makes it much easier to replace if it blows again.

Thank you, Mike. I appreciate you taking the time. Glad I'm on the right page.

Oh, okay. Butt splice is fine by me if there are no issues with that for longevity. Curious if a 16-gauge fusible link and the thick red harness wire will both fit in the same diameter butt connector on both sides.

[Steeveedee]

One thing I'd like to point out before replacing a lot of parts. I've seen brand new cars towed into the shop with burnt fusible links that needed nothing other than the wire replaced. They really are like a fuse, and some conditions cause them to fry, but then don't do it again. Is there anything out of the norm in this instance?

[harrydunn]

Originally Posted by Steeveedee

One thing I'd like to point out before replacing a lot of parts. I've seen brand new cars towed into the shop with burnt fusible links that needed nothing other than the wire replaced. They really are like a fuse, and some conditions cause them to fry, but then don't do it again. Is there anything out of the norm in this instance?

It was extremely hot in the shed when I cranked it up yesterday. Other than that, it was on the battery tender like usual since the last time I drove it two weeks ago.
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[Steeveedee]

If it were mine, I'd take the truck to a parts store that has the equipment (after you replace the fusible link) and have the charging system checked out while intact. I'd really not want to start tearing into it until the actual problem was evident.

[Stocker]

Originally Posted by harrydunn

Thank you, Mike. I appreciate you taking the time. Glad I'm on the right page.

Oh, okay. Butt splice is fine by me if there are no issues with that for longevity. Curious if a 16-gauge fusible link and the thick red harness wire will both fit in the same diameter butt connector on both sides.

I used butt connectors, no issues though I *may* have needed to stretch one a bit to go on the red wire. If so, it was easy. I always solder & heat shrink all connectors and have never had a problem. By all means do whatever you're most comfortable with. There's certainly nothing wrong with a hard-soldered joint.

[harrydunn]

Originally Posted by Stocker

I used butt connectors, no issues though I *may* have needed to stretch one a bit to go on the red wire. If so, it was easy. I always solder & heat shrink all connectors and have never had a problem. By all means do whatever you're most comfortable with. There's certainly nothing wrong with a hard-soldered joint.

Butt connector for testing is certainly a good choice. I’ll report back tomorrow after I get the new fusible link on.
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[harrydunn]

**UPDATE**

Well, this is interesting. I wired in the new 16-ga fusible link this morning. Popped the battery back in and started to hear ticking over by the alternator and the same electrical smell as when this all started. Look over and the alternator is smoking! Yes, the battery was connected the correct way. Only one way to get the cables to reach and I can verify the negative ground to the block. I've attached two photos. First photo is self expalatory. Second is the red wire on the back of the alternator. Wondering if my alternator finally gave up the ghost after 15+ years? Smoke seemed to be coming from the alternator interior.

Also, before doing any work I got on my creeper and checked all of the wiring I could. I see no evidence of roden damage.

Thoughts? Time for a new alternator obviously but I wanted to post here first. This isn't my daily so I can take my time. Thanks as always!

[rockyrivermark]

I would buy a new one wire internally regulated alternator.
They are reasonably priced

[harrydunn]

Originally Posted by rockyrivermark

I would buy a new one wire internally regulated alternator.
They are reasonably priced

Down the road perhaps but I don't want to add any more variables to figure out the issue at the moment.

[MARKDTN]

I would take the alternator and have it tested. I believe you have an internal short. This would be a great time to convert to an internal regulated alternator. I would NOT do a 1-wire version. It is a bolt-on swap with minimal wiring.

[harrydunn]

Originally Posted by body bolt

I second this although his alternator does appear to be internally regulated.

I’ve still got an external regulator with all wiring in place running to the ALT.
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