Date: Sat, 19 Apr 2008 20:48:13 -0700
Reply-To: neil N <musomuso@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: neil N <musomuso@GMAIL.COM>
Subject: Re: '86 Westy cranking trouble
In-Reply-To: <5F8C30BA-D1E7-4475-B697-6F7F7FE4D4D2@WESTAL.NET>
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On 97.88 and 97.89 of Bentley, one connection from coil goes to track
34, which goes to one side of the coil on the digifant control unit
relay. Not the fuel pump relay.
Both fuel pump and digifant control relays are supplied with 12V from
30 (B+) to one side of the "switch" in the relay.
When the ignition switch is turned to position 15, (ign.) 12V goes to
a connection on the primary side of the ignition coil. From there it
goes to 4/86 of the electromagnetic coil on the digifant control unit
relay. The coil is energized, and this closes the relay which sends
power to the digifant control unit. The FP relay is energized when a
ground connection is "sent" by the Digifant Control Unit. AFAIK, this
happens when the engine is cranking, or when it is running. i.e. if
the engine were to stall, the fuel pump relay would stop.
I would check for dirty connections at the relays in question. I would
also check for dirty fuse connections though I bet you have the more
modern fuses. Not the old style ones.
Neil.
On Sat, Apr 19, 2008 at 7:49 PM, Dan Hall <elektro@westal.net> wrote:
> I have an '86 Westy Weekender, Wolfsburg edition---pop-top but no
> kitchen.
>
> In the past several weeks, I've had a mysterious, intermittent
> starting problem. The starter works and the engine turns over fine
> but won't crank.
>
> The fuel relays and, thusly, the fuel pump were not cycling when I
> turned the ignition switch.
>
> I discovered that if I lightly tapped on the fuel relay box above the
> coil with the key switched on, the relays would click on and the fuel
> pump would cycle and I'd start it up and off I'd go.
> Thinking it was bad relays, I bought replacements. That solved nothing.
> I've since bench tested the relays and they work fine.
>
> The big red wires that supply constant current to the fuel relays have
> 12 volts.
>
> There is a black/yellow wire that runs from the fuel relay to the
> coil. The Bentley says this wire is Black/White but mine is black/
> yellow. With the ignition switch on, I only had 5 to 6 volts on this
> wire. Tap the relay with power on and the relays work, fuel pump
> cycles. Then, I tried to start the van as usual after and it turned
> over fine but would not start. Now, that same black/yellow wire shows
> only 1.2 volts. The relays will not work, even with tapping.
> I plugged in a borrowed Digifant ECU but that did not help the
> situation. I put the old ECU back in.
>
> I ran a jumper wire with 12 volts to that black/yellow wire on the
> coil and the relays and fuel pump all worked nomially.
>
> I had a spare ignition switch and tried that but no joy.
>
> I've studied the wiring diagrams of the Bentley til I'm cross-eyed.
>
> Where does the coil get its voltage supply?
> ----My Bentley shows from a relay in the 2 position on the panel next
> to the fuses in the wiring diagrams but not in the legend of the same
> pages. And I've never had a relay in the 2 postion.
> -----I tested the resistance of the coil and it seems within
> specifications.
>
> What voltage should I have on poles 1 and 15 on the coil with the
> ignition turned on?
>
> I have thought about leaving the 12 volt jumper wire hooked up the
> coil and then try starting it but am holding off til I hear from the
> List.
>
> Any help, advice, guesses would be appreciated.
>
> Dan Hall
> '86 Westy Wolfsburg Weekender
> "Das Boot"
>
--
Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
http://web.mac.com/tubaneil
http://tubaneil.googlepages.com/
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