Cooking alternator and starter in 1HD-T (1 Viewer)

Joined
Oct 23, 2018
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Hi all,

I have an issue to solve.

During my 1FZ-FE (out) / 1HD-T (in) engine swap project I have been slowly going through the newly installed old electric system that fits the 1HD-T. During the installation, the 3 connector plug (IG, S, L) on the alternator back wasn't connected but only the main power cable. I didn't install the engine my self and didn't notice this until yesterday. When I finished connecting the alternator and measured the batteries while running, the voltage slowly increased up to 14 volts and I decided to do some tests with the lights etc. When I placed the voltmeter on the batteries with the lights on, the charging had stopped and the batteries were falling 12.5 volts and going down, rather fast. When I then switched off the truck the alternator was smoking. I decided to wait a bit, let it cool down, start again and measure after hitting the alternator with a hammer to see if the coils were stuck, but when I switched on the truck, it started immediately, with out me turning the key into the start position. The starter then didn't pull the bendix back into the starter - so I immediately turned of the car.

Therefore, now before having the smoking alternator repaired, I want to figure out why this happened. I find the behavior of the starter strange, it did start OK before connecting the 3 connector plug on the alternator (IG, S, L). I have been going through the electrical system, and finishing missing bits here and there (for example the voltage converter timer and relay weren't connected) and I thought I was going in the right direction, until yesterday after 5 minutes of extreme happiness and then what now seems to be an endless sadness...

Any thoughts on this? Could a faulty starter smoke the alternator? Or could a faulty relay or wiring smoke the alternator using the starter for the task?
 
Joined
Oct 23, 2018
Messages
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Iceland
To clarify - the truck is now able to start with key in switch at "On" position.
Any thoughts?
 
Joined
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Messages
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Is there someone here that could explain the purpose of the 24 Volt Hold Warning Relay to me?
It seems to be grounding the Alternator Terminal L.
Why?
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Joined
Dec 8, 2006
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You may have more luck posting this in the diesel section.
If the starter is cranking over with the key in the ON position, then the starter relay logic is wrong.
Also, why would you hit an alternator with a hammer? There is nothing to get "stuck" and a hammer is not a volt meter.
It appears as if the 24V hold warning relay disables the alternator during 24 volt start, but I could be wrong about that as I don't have the rest of the schematic.
 
Joined
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Messages
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Location
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You may have more luck posting this in the diesel section.
If the starter is cranking over with the key in the ON position, then the starter relay logic is wrong.
Also, why would you hit an alternator with a hammer? There is nothing to get "stuck" and a hammer is not a volt meter.
It appears as if the 24V hold warning relay disables the alternator during 24 volt start, but I could be wrong about that as I don't have the rest of the schematic.

Thanks. Will get it into the diesel section. My guess was the 24V hold warning relay disables the alternator, but I don't know.
(About knocking it with a hammer, I was simply following an advise from a mechanic to see if the brush set / solenoids could be stuck. Not deeper than that.)
 
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Joined
Dec 8, 2006
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9,724
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Thanks. Will get it into the diesel section. My guess was the 24V hold warning relay disables the alternator, but I don't know.
(About knocking it with a hammer, I was simply following an advise from a mechanic to see if the brush set / solenoids could be stuck. Not deeper than that.)
An alternator does not have solenoids. I think you're confusing the alternator with the starter.
 

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