Cucv battery blew up

Laszlo

New member
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Alabama
So my cucv was on its way to its first a car show with my wife and son. The cab started smelling like rotten eggs. I popped the hood and the battery closest to the firewall was smoking. Its a 24 volt system still. So I make it to the auto parts store. At the store after replacing the batterys the " firewall " battery isnt charging. By the time I get home its running 16.7 volts.is this too much also my volt meter has never worked i tryed replacing the 300 ohm diode . still doesnt work. My gen 2 light isnt lighting at startup.. Its a real bummer cause I worked on this truck so much and have done everything I could up to now trying to het it right.

1. Does an alternator charge properly if the gen light isnt working?
2. Whats an acceptable voltage range for charging?
3. Will the system operate properly without the voltmeter working?
 

NDT

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Camp Wood/LC, TX
13.8 volts is what the voltage regulator is set for. When the voltage regulator fails, you get a boiling battery like you got.
 

Skinny

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Portsmouth, NH
I would want to know what both alternators are charging at regardless of what the lights are doing.

Don't let it get you down, these things are really old. They take a lot of miles to work the bugs out. I remember one of my regulators failed right after rebuild. Since then they had 10 years are trouble free work.
 

Laszlo

New member
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Location
Alabama
Car shows can be expensive. If the wiring touches the frame that smell can leak out. Check that wiring. If I did your wiring you'd look for stuff like this around the starter.

View attachment 848119 View attachment 848120
I Checked the wiring nothin obvious. I ordered two rebuild kits for the alternators. Two new batterys and a gear reduction hillbilly wizard starter and bracket. Im gonna rebuild both the 27si and the non isolated geound gm alternators I have on there and see how she does.
 

WWRD99

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York Pa
I Checked the wiring nothin obvious. I ordered two rebuild kits for the alternators. Two new batterys and a gear reduction hillbilly wizard starter and bracket. Im gonna rebuild both the 27si and the non isolated geound gm alternators I have on there and see how she does.
I just rebuilt mine last night...very easy to do...only suggest taking a pic of the inside and out just so you don't second guess yourself!! The kits are very complete and both of mine now work great.
 

Laszlo

New member
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Location
Alabama
I have another question. There is a temp sensor near the firewall. I want to replace it. I go to oriellys and they look at me like I'm crazy. What do you guys tell people at the parts counter these things are?
 

Laszlo

New member
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20
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Location
Alabama
I just rebuilt mine last night...very easy to do...only suggest taking a pic of the inside and out just so you don't second guess yourself!! The kits are very complete and both of mine now work great.
You guys are so supportive. Awsome community here. I really appreciate this site. I would have never made it this far with this cool old truck without you guys.
 

WWRD99

Well-known member
Steel Soldiers Supporter
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Location
York Pa
I have another question. There is a temp sensor near the firewall. I want to replace it. I go to oriellys and they look at me like I'm crazy. What do you guys tell people at the parts counter these things are?
What I did was find the parts and illustration book and downloaded it...it's 491 pages...half way down it starts to show pics...it has a pic of the truck on the front 84-87 on it...it might be in the tm section of this site too...it has every part blown up in sections with every part number for it...I copy and paste the part number then search for it...you'll find about everything that way...I have had very little luck at parts stores since most have no clue what a temp sensor is plus this engine uses more than one.

Sent from my SM-G955U using Tapatalk
 

Laszlo

New member
17
20
3
Location
Alabama
So I got both alts rebuilt the isolated ground alt was alot more involved. I got it wrong the first time. Had the common wire on the wrong side of the rectifier. But I got them all back together now. And I suspect i need those gen lights working. To excite the units. Before it was stuck wide open. Unregulated. After the rebuilt im not producing but 12.9v of power. Im gonna dig into the dash and check the bulb for my gen 2 indicator. On another note. Those guys at Hillbilly Wizard are some great folks. Wow. Fast delivery. I cant say enough very happy they do what they do. She still aint perfect but shes running again.
 

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Laszlo

New member
17
20
3
Location
Alabama
A slightly different question. At approx what temp does the glow inhibitor switch call for glow plugs ? Like first start on a summer day. Should it cycle the glow? Today it was 52' this morning. No glow cycle. If I unplug the inhibitor and try it. The glow plugs come on no issues. Is it just not cold enough yet? Or is my original style OEM switch bad?
 
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