Date:         Sun, 30 Oct 2011 14:02:46 -0400
Reply-To:     Gregg Carlen <gregg.carlen@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Gregg Carlen <gregg.carlen@GMAIL.COM>
Subject:      Alternator Troubleshooting
Content-Type: text/plain; charset=windows-1252

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)