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Charging circuit question

dl242gt said:
If I was buying on line I would consider the FCP Euro option as they have the best warranty. While you don't get a great warranty Rock Auto and Parts Geek have good prices as well.
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I checked FCP. Theirs is on back order. I am leery of rock auto. But they have remaned Bosch. Maybe I’ll get brave.
 
bobxyz said:
Did they say what the problem was? Testing an old alternator should be really easy for them.
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well at advanced it was for sure the operator error. At auto zone, the machine said it was shorted. I never tested for an internal short. So I guess I’m going off his word. I decided to move on from that problem and hope I get a good one from either IPD or rock auto.
 
Ok. New alternator in, same symptoms. I felt froggy so I replaced all the fuses under the dash with new ones. No change. Scratching my head fellas. Any other ideas?
 
Oh, that's a big disappointment. The wiring should be really simple, with just 3 wires:
1) big ground wire from body of alternator to nearby engine block bolt
2) big +12v wire bolted to alternator and running around the front of the engine block to the starter, where it's bolted down along with the big battery +12V cable
3) small DF+ wire to the cluster alternator light

Do you have any other wiring, maybe something left over from the external regulator that hasn't been removed? Is the +12v battery post clamp tightened down and not just shoved on by hand?

I forget, have you measured the voltage drops (when running) between a) alternator body and chassis ground, and b) +12v stud on alternator and battery + post ?
 
bobxyz said:
Oh, that's a big disappointment. The wiring should be really simple, with just 3 wires:
1) big ground wire from body of alternator to nearby engine block bolt
2) big +12v wire bolted to alternator and running around the front of the engine block to the starter, where it's bolted down along with the big battery +12V cable
3) small DF+ wire to the cluster alternator light

Do you have any other wiring, maybe something left over from the external regulator that hasn't been removed? Is the +12v battery post clamp tightened down and not just shoved on by hand?

I forget, have you measured the voltage drops (when running) between a) alternator body and chassis ground, and b) +12v stud on alternator and battery + post ?
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It is a big disappointment.

I did the drop tests with the last alternator. I can do them again for this one.

All connections are tight. I can probably get some wire and loom and rerun everything.
 
ZVOLV said:
You may be chasing your tail. Compare to like-vehicle to determine if this is normal.
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ZVOLV said:
You may be chasing your tail. Compare to like-vehicle to determine if this is normal.
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Any idea how I’d find that out? I’ve been trying to find a data point for this. And everything I’m reading says 14v with the car on. But I’m not sure if I’m draining. I haven’t left it running or driven it in this configuration. I suppose I should drive it to see if it goes below 12v.
 
You may be worrying for no reason. I don't always expect to see 13's and 14's.

You could also drive to an auto parts store and see what their on-car tests say.

I will go check on my 1984 240 with B230FT swap.
 
ZVOLV said:
You may be worrying for no reason. I don't always expect to see 13's and 14's.

You could also drive to an auto parts store and see what their on-car tests say.

I will go check on my 1984 240 with B230FT swap.
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I appreciate it. Thank you! I’ll give that a try that’s a good idea. I have an advanced like 5 min away. I’ll bring my jump pack just in case.
 
Ok new info. Found an engine electrical guru in my neighborhood (of all places). Drove it over to him and he looks at it for 5 seconds and tells me my belt pulley is slipping. I’ll be damned it is. He said to fix that and come back to him for him to test my charging system. So now, does anyone have a line on an alternator pulley for dual v belt?

I found this part number online for one. (3544584) But I want to make sure it would be compatible.

I also need an alternator tensioning bolt. I think there’s just a random all thread in mine with a nut. Anyone know that pn? Thank you all!
 
ZVOLV said:
I was about to say check the belt tension.
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Well I have it to spec.. but he says it’s still too loose. Which makes me think I should probably see if I can find a pulley. I’ll try tensioning it when it’s cold. And see what happens. I’ll probably replace the belts too.
 
You need a 90mm long m6, it'll be a lot cheaper from a hardware store, add a washer under the head. The belt should deflect about 10mm when properly tensioned. Try new belts and proper tension before replacing the pulley.
 
Radtap said:
You need a 90mm long m6, it'll be a lot cheaper from a hardware store, add a washer under the head. The belt should deflect about 10mm when properly tensioned. Try new belts and proper tension before replacing the pulley.
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Ok good tip! Thank you! I will do this Monday. (I work all weekend)
 
Also compare the pulley size between your new and old alternator, if you got a denso you'll need shorter belts, 10x920mm iirc. Always buy the alternator/water pump belts in pairs otherwise one may be looser than the other, belt wrap sucks on the alternator so you need everything you can get.
 
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