Not-Charging Frustration

[idi_econoline]

Howdy, all. Been a while, again.

Fine, so, vacuum booster failed, and brake fluid bad, so replaced booster and MC. Bleeding took forever.

As soon as I started her up, the factory volt gauge read low, like 10.5 volts. Multimeter showed 12.5 or so. Tested batteries, one bad. Replaced. Charged both to near 100%. Gauge still reads low. Alternator not charging at all, even at speed.

Replaced alternator. No change! Grrrrrrrrrrrr

What's left? Wiring to the alternator? But why would that change when I never touched it before the no charge?

TIA

 

[IDIBRONCO]

Do you have V-belts? If so, you probably have a 1G alternator. Those have an external voltage regulator so changing the alternator won't change anything if that's bad. Here's a couple of pics of a 3G alternator. They aren't real good, but it's all that I could find with just a quick search of my pictures. Since you just changed yours, you should still be able to tell which one you have.

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[Philip1]

If you have a 1g alternator you will find a small box on the passenger fender that looks like this. It will be the voltage regulator for the alternator

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its best to replace it when you replace the alternator as well.

 

[stick_witch]

Like @Philip1 mentioned, if you're still using the stock 1g style alternator setup, there is an external voltage regulator on the passenger side wheel fender (note: this is where it is located in the trucks, not sure about the vans, but just follow the 2 pin pigtail connection from the alt and it should lead you to it). These are prone to going bad and should be replaced before or anytime you replace the alternator. If that doesn't do it then there is a good chance you have a bad connection and I'd go through and check and clean the grounds and terminals. But, chances are its just that voltage regulator, although the stock charging systems in these idi's are pretty famous for being horrendously underpowered and terrorizing any who dare to try and make them work properly. It's pretty much a standard practice in the idi community these days to throw away the old, stock 1g and 2g swapped alternators out and throw in a 3g. So really, if I were you, I'd save yourself the future headache and just do a 3g swap. Tons of good info out there on how to do it and it's super easy, and is leaps and bounds better in performance, especially if want to run any accessories. Just my .02.

First pic is what the 1g (1st gen) alt resembles (external cooling fans, external voltage regulator and 2 wire connection + 2 prong pig tail connection).
Second pic resembles the 3g (3rd gen) alt (internal cooling, internal voltage regulator, 1 wire connection and 3 wire pig tail connection)

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[Shadetreemechanic]

If you stick with your 1g alternator, make sure you buy a quality voltage regulator. I like the motorcraft ones myself. A lot of the cheap ones are bad off the shelf or don't last long at all.

 

[idi_econoline]

Thanks, 1992, so 3G before and after.

 

[idi_econoline]

In an offline discussion with a member here, he suggested that the one remaning "old" battery is the problem. It load tests fine, though.

 

[riphip]

Bad battery will ruin a good battery. In these diesels, change both as a pair or continually have problems.

 

[idi_econoline]

Major duh! TYVM, riphip.

Now remembering my charger stopped once, while individually charging that old battery. The indication was "bad." Unplugged, and it took the charge, but.... yeh.

 

[The_Josh_Bear]

Bad battery will ruin a good battery. In these diesels, change both as a pair or continually have problems.

Words to live by around here!

 

[Cubey]

(note: this is where it is located in the trucks, not sure about the vans, but just follow the 2 pin pigtail connection from the alt and it should lead you to it)

On my 85, it's right by the passenger side headlight, next to the starter relay.

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[IDIBRONCO]

although the stock charging systems in these idi's are pretty famous for being horrendously underpowered and terrorizing any who dare to try and make them work properly.

Very well said. I'm still chuckling about this.

Thanks, 1992, so 3G before and after.

If it had been a truck, I wouldn't have suggested it being a 1G, but the vans seem to run a little behind on technology so I wasn't sure.

 

[stick_witch]

Thanks, 1992, so 3G before and after.

Right, the 92 vans came with the 3g stock. Then definitely a bad connection or bad battery. Like @riphip said, if you had one bad battery, you pretty much have to replace both. I would also check for a fuse on the output, if it has it.

 

[stick_witch]

Very well said. I'm still chuckling about this.

Thanks! Hahaha ask me how I know... just started daily driving mine and as soon as the temp started dropping up here I now can barely make it through my errands. God forbid I turn the blower on to heat up the 40 degree cabin... just gonna skip the bs and put a 3g and some new batteries and be done with it.


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[The_Josh_Bear]

Howdy, all. Been a while, again.

Fine, so, vacuum booster failed, and brake fluid bad, so replaced booster and MC. Bleeding took forever.

As soon as I started her up, the factory volt gauge read low, like 10.5 volts. Multimeter showed 12.5 or so. Tested batteries, one bad. Replaced. Charged both to near 100%. Gauge still reads low. Alternator not charging at all, even at speed.

Replaced alternator. No change! Grrrrrrrrrrrr

What's left? Wiring to the alternator? But why would that change when I never touched it before the no charge?

TIA

One battery bad or not, your engine-on charging situation is totally separate.
You said the gauge was low when running but did not list the charging voltage from the multimeter; could you update with that?

Also a new alt doesn't guarantee that the new regulator is working correctly. However more likely is that the sense wire to the regulator has a bad connection or cracked or something and isn't telling the regulator to "turn on". This is the yellow/white stripe wire that goes to battery+. Grab that multimeter and do an ohm test on that wire, only takes a second to verify. You can also do a voltage test on it, same thing since it carries 12v all the time.