Before I buy a new alternator...

[Ftbagkicker]

Long time E30 fan, just purchased '89 325i 4dr weeks ago and need help with what I think it's an alternator issue.

Multimeter Test:
Not started = battery tested at 12.6v
Started = battery tested at 11.78
Started for 1 min = battery tested at 11.68
Started for 4 mins = battery tested at 11.50
Started for 6 mins = battery tested at 11.35
Started 6 mins (2k RPM this time) = battery tested at 11.25

The pattern is obvious. Also, it looks like the voltage regulator has been replaced (old one in ashtray). Before I go buy a Bosch reman alternator, is it the culprit for sure? Thoughts?

[TobyB]

Probably.

Less likely, could also be alternator connections...

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[uturn]

Check the wiring, there needs to be power to the alternator field windings before it can start to charge. If it's confirmed there's power then yes, you're alternator is shot.

[Ftbagkicker]

There're only two ground wires, correct (from what I read)?

[uturn]

It should already be grounded via the engine if not then by #4. #2, the large bolt goes to the battery, #2, the small bolt should have battery voltage when you turn on the key.

[Ftbagkicker]

Thank you, uturn (I can't enlarge image).

BTW, is the alternator the same through the years? May pick one up from a part out car. Also, what's the best place to buy reman Bosch? Sorry, lots of noobie Qs.

[jlevie]

Does the battery warning light come on when ignition is switched on? If it doesn't the alternator wont charge. Before getting a replacement alternator, pull the requlator and see if it is fact a new part. The PO could have swapped in a used and worn part. The length of the brushes will be a clue.

[uturn]

The original picture and light reading. http://www.e30owners.com/forums/show...t=4446&page=17

[Ftbagkicker]

uturn... thank you. I can't believe it. Pulled the alternator today, didn't see anything visual wrong, then saw your link to pic. Check out my alternator! I don't have (#4) ground wire at all!!! WTH? Could the PO lost it? Who would have forgotten it? Luckily, I ordered the wire kit from Gregs///M.

So, my question is = was my low readings due to the missing ground wire? BTW, the two wires (#2 in link) was properly attached.

[FLG]

The alt will ground though the bracket. Only used in alts with rubber bushings

Sent from my SCH-I545 using Tapatalk 2

[jalopi]

Dude take the alternator to autozone or somewhere like that, they will test it for free.

[lcoleman]

That alternator certainly looks like it's toast. You can pull the voltage regulator out to learn more. Since the VR has already been replaced once, I am guessing that the slip ring is in bad shape and your best course of action is to buy a new (not remanufactured) or low-miles OEM one.

As stated, that later-style alternator grounds through the bracket.

[Ftbagkicker]

Got a used alternator from a member who has an E30 warehouse. Put it on, started the car, ran it at 2k RPM, and got a reading of 13.7v... can I rule out the regulator? I'm monitoring the battery.

BTW, had to take a pic w/ my FZJ80.

[jalopi]

voltage isn't the only thing you've gotta look for when testing alternators. yeah, it's a pretty good indicator of how well they're working but to get that good test on you gotta look for charging amps. autozone & other places will do this for free.

also, that generation of land cruisers are fucking awesome.

[Ftbagkicker]

Thank you, Jalopi. My land cruiser will probably out last me. It has never let me down.