Date:         Fri, 03 May 1996 11:09:00 -0700 (PDT)
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         "Maher, Steve (SD-MS)" <SMAHER@gi.com>
Subject:      '80 Vgon gas gauge specs?


Anyone know the internal resistance of the gas gauge in an '80 Vanagon?
Bentley says that the sensor varies from about 50 ohms to around 500
ohms, full to empty (sorry, I don't recall exact figures). But Bentley
never mentions the resistance of the other part of the circuit: the
gauge itself.

The V6anagon's gauge has never read accurately. For the longest time,
when you filled it up it would read between 1/2 and 3/4 full. I
checked the voltage stabilizer (OK), measured the sensor resistance
(OK), and tightened a lot of connections. Helped slightly but not
much. Then I bypassed the stabilizer and wired the gauge power directly
to 12VDC, which of course varies from 11.5 to 14 depending on how the
alternator feels that day (hence the need for a "stabiliser", or
voltage regulator as we call them here in the colonies). With the
stabiliser bypassed, the needle goes right off the gauge when the tank
is full and alternator is alternating. When I stop the engine, the
gauge sits on the full mark (hallelujah!) with the key on.

The cause is probably dirty contacts where the gauge wire connects to the
tank sensor. But I've heard that you have to disassemble the entire bus
to get to it, so I haven't tried. Yet.

I may eventually stick a temporary 1-ohm resistor in the line to get a
reading of gauge current, but I thought I'd ask if anyone has already
done this, or found out in some other way what the current flow normally
is in this circuit.

I might also put a 7812 or LM317 in place of the stabiliser, in a
sleazy attempt to compensate for whatever's wrong with this thing.
It won't be too effective at lower (<13V) supply voltages, but it may
work with engine running. Hopefully I can avoid having to go after
the sender contacts (i.e. fixing it right).

    _______
   /\ o o o\         Steve Maher   smaher@gi.com   75461,1717
  /o \ o o o\_______   San Diego, California
 <    >------>   o /|
  \ o/  o   /_____/o|      '80 VW V6anagon
   \/______/     |oo|        '66 Mustang Coupevertible
         |   o   |o/       '89 Son Sherwin
         |_______|/
                     http://www.lookup.com/homepages/76242/home.html

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