Alternator not charging

[east302]

That’s pretty low for a healthy alternator, but you would need to rule out a cable issue first. What is the alternator voltage measured from the alternator post to ground? Rev it to around 1500-rpm and compare.

Try what Ken said, put one lead on the battery positive and the other on the cable post at the back of the alternator. It should be a low number, less than 0.5V.



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[Wade]

From alternator post to ground is at 12.48 volts, when I rev the engine it stays the same.

Measuring from alternator post to battery + lead reads 0.01 volts.

 

[Wade]

Just making sure I don't miss any here, these are the grounds I've checked: Alternator mounting, batt to engine block, batt to fender, I made a new one from battery to frame, engine to firewall.

 

[east302]

From alternator post to ground is at 12.48 volts, when I rev the engine it stays the same.

Measuring from alternator post to battery + lead reads 0.01 volts.

Yeah, the alternator isn’t doing its job.

The drop across the cable looks good.


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[Supercharged111]

Do you have 12V at the small plug? That's what turns the alternator on. Just spinning the pulley won't excite the alternator.

 

[Wade]

Do you have 12V at the small plug? That's what turns the alternator on. Just spinning the pulley won't excite the alternator.

I assume it does because the idiot light turns off when it is removed, but I'll test it in the morning when I get crackin` again.
Someone at work also told me I should check out the starter solenoid. I'll get it eventually

 

[Jared Jackson]

As an ASE Master Tech since 1978, I grew up rebuilding alternators, carburetors, distributors, starters, etc. I hate the new "BOX" fixer's. If you don't perform best practices first by testing, the trips to the store will increase...with your box & receipt.

Nowadays, it's more cost and time effective to just swap in assemblies. I am guilty of some things you might hate. If I can buy a control arm assembly where I don't have to press anything in or out... I am buying that assembly! Strut goes out... I am picking up a quik strut! Engine goes... Long block all day for me. I think you were leaning more towards not doing the proper troubleshooting and just throwing parts at it, which I try not to do in most cases... I do have a rule though... if the part I think is broken is a likely culprit and the collective internet has had the same problems with the same symptoms as I have, and they suggest that part, and it's under 40 bucks, I am just going to buy it and try it.

 

[Wade]

Well, more diagnostics on my part lead to the alternator. So in a last ditch effort I pulled every bolt and grounding strap, polished the surfaces, and replaced. Nothing, not a ground problem. Took out the alternator and took the only running vehicle I have left, a motorized Schwinn bicycle, to auto zone to get it tested. Came back bad. Went back to Carquest for my warranty. On the bench test it sounded like running over a sprinkler head with your lawn mower. "Doctor, I think it's a bearing!" I got my replacement. Runs great now, 14.7 volts.

 

[DallasTahoe]

Well, more diagnostics on my part lead to the alternator. So in a last ditch effort I pulled every bolt and grounding strap, polished the surfaces, and replaced. Nothing, not a ground problem. Took out the alternator and took the only running vehicle I have left, a motorized Schwinn bicycle, to auto zone to get it tested. Came back bad. Went back to Carquest for my warranty. On the bench test it sounded like running over a sprinkler head with your lawn mower. "Doctor, I think it's a bearing!" I got my replacement. Runs great now, 14.7 volts.

Sounds like post #2


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[Wade]

Sounds like post #2


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Yeah, you were right. Odd that the first time I tested it at Carquest it came back good.