Hi folks, I'm hoping I can tap into the collective wisdom of the list for
some light Sunday afternoon troubleshooting help.

Background: 91 Westy, 2.1l, automatic. Northern Virginia area.

My battery light came on yesterday during our icky weather. At first, it
was faint and appeared to be flickering, but quickly became steady �on�. As
I would expect, after about 15-20 minutes of driving with headlights,
windshield wipers, rear heater and rear defroster on, I lost power and the
van stalled.

On the side of the road, I put my voltmeter across the battery and got ~7
volts. Dead battery. Connected my portable jump-starter battery pack,
waited a few minutes, and started the engine (without headlights, minimal
use of wipers and all other battery drains turned off). If I turned off the
jump-starter, within 30 seconds the engine would stall out. If I Ieft the
jump-starter on, the van would start and I drove it for another 10 minutes
to get off the highway and to the parking lot of a gas station (where it
stalled out again because the jump-starter was drained by this point).

Weather turned worse and called AAA for a tow. Ran out last night and
picked up a rebuilt Remy-brand after-market 90A alternator (just in case I
would need it the next day).

Now that I�ve got a chance to check things out, here�s what I did:

Before starting anything, I charged the starting battery, checked
terminals, alt belt tension, cleaned wire connections to alternator.
Re-started the engine and the alt light came on, strong and steady. Volt
meter across terminals B and D resulted in about 7V.

Thinking to just jump all in and swap the alternator, I quickly realized
that the pulley�s were different between the alternator in the van and the
rebuilt one in the box, so no-go for a quick and easy swap since I don�t
have an air compressor strong enough to power an air-wrench to �bump� the
retaining nut on the pulleys. Tried holding it with a vice and such, but
really it�s on there tight. For reference, the pulley on the alternator in
my van (which has a �remanufactured� label on it, looks like the v-belt
pulley on 27.17 in Bentley. It�s up close to the fan. The rebuilt
replacement alternator I picked up last night from FLAPs has a pulley that
looks like the one for a 45A/65A alternator on page 27.16 and the 90A
version on 27.15. (The rest of the alternator looks like the 90A version on
27.17).

So, some quick testing with a voltmeter:

Test 1: with the engine running, I put my positive lead on terminal B and
the negative lead on terminal D. The voltage was 7.1V. Battery light still
on dash.

Thinking this is a bad voltage regulator or brushes, I pulled the voltage
regulator out. A little grimey at the metal contacts, but the brushes
looked fine. Cleaned the grime off and re-installed the regulator. Restart
the engine and check voltage across terminals B and D and I get 7.1V.
Battery light still on dash.

Just for kicks, I pulled the regulator out again compared it against the
one in the new alternator from FLAPs and they look identical physically.

Test 2: Installed the new voltage regulator into my old alternator. Started
the engine and tested across terminals B and D and I get 6.9V. A few other
measurements at this point (wish I had taken them in previous tests):

Terminal B to alternator housing: 11.75v, dropping to 11.5v after about 30
seconds

Terminal D to alternator housing: 4.57v

So, given that information and testing, I�m thinking either I have a bad
alternator (diode, perhaps) or I�m chasing down the wrong path altogether.

One other caveat to mention: on my original alternator, the suppression
condenser was not mounted the same as the new alternator from FLAPs (which
was connected to terminal W and the alternator housing). Mine has had the
connector cut off and mounted to Terminal D, and the condenser itself had
the hole enlarged and mounted to terminal B. Don�t know that this would
cause an issue, but thought I�d mention it. It�s been this way since I
acquired the van earlier this year.

Any thoughts or advice on other things to check? Or, next steps to take? Do
I replace the alternator at this point (find a way to swap the pulleys or
get a replacement one with the correct pulley)?

Thanks in advance!

Gregg

91 Westy (Blueberry)