Date: Tue, 24 Jun 1997 03:59:11 EDT
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: uvx196@juno.com (Jim Thompson)
Subject: Re: Fuel Gauge inaccuracy(pessimistic vs optimistic)
Well, with Ari and myself sharing 35 years each (or so) or VW ownership
(with him owning a few Porsche's to boot) we seem to be at opposite ends
of the sprectrum when it comes to viewing gas gauges and their accuracies
(or lack thereof). But I'm sure there's others out there that have more
accurate gauges.
As far as driving or using VW's with "pessimistic" gas gauges, I have
driven those too. Never owned 'em, but have driven some on occasion.
The worst case of "optimism" though was with my 67 Deluxe Bus (bought
that new too - going to a VERY good home this coming weekend). Never
could get the hang of reading that gauge right in over 30 years. I just
made sure that I filled up when the odo said to.
With all the electronic felgercarb in the dashpod of a LATE VW (re:
voltage stabilizers, etc.,) I wouldn't be surprised at inaccurate
readings of the water temp gauge as well - which is why a separate VDO
gauge with numbers is installed as well to really tell me what's going
on.
Of course there are American and Japanese makes that aren't all that
accurate either.
Chris (JordanVW@aol.com) makes a very valid point of inaccuracies
regarding people using used/junkyard tanks that have been banged or bent
up with the forklift method. But I don't think that's the problem in
your situation. It could very well be a bad voltage stabilizer in the
dashpod - especially if the dang gauge is reading 1/2 full and it runs
outa gas (and the sender is in good shape of course). But I believe (and
I could be very wrong) that the same voltage stabilizer works with the
temp gauge as well, so that MAY be wrong as well. I know you'll figure
it out sooner or later, because I know it can be unnerving to have
inaccurate information.
But I just felt that what I have experienced for over 35 years myself was
worth looking at. Sometimes you just can't fight fate, satisfy karma or
please everyone. Everyone's experiences are different and unique.
That's what makes the human race, much less VW owners special, right?
Jim
84 Westy 2.1 * 62 Beetle (Father was orig. owner)
Sherwood Automotive * The Old Volks Home (oldvolkshome1@juno.com)
On Tue, 24 Jun 1997 01:40:34 -0500 Ari Ollikainen <ari@interserve.com>
writes:
>Jim Thompson wrote:
>>
>> Ari -
>>
>> Vanagon gas gauges have a notorious habit of becoming "optimisticly"
>> inaccurate when the fuel level gets low and close to the red zone
>> (so-called reserve area) of the gauge. Generally speaking from the
>> owner's manual, when the needle hits the red you're supposed to have
>2.5
>> gallons left to get yerself to a gas station. I've seen it dip as
>low as
>> half-way thru the red zone on the gauge. However when the tank
>finally
>> empties out, the sender (or the gauge - or both I really don't know)
>has
>> the habit of causing the needle to slightly drift back up showing
>just
>> over a quarter of a tank of fuel left to drive on.
>>
>> This has happened in my 80 Vanagon (now sold off) and I have a few
>other
>> friends with Vanagons that this has happened to as well. When your
>tank
>> empties out (as you and maybe others have found out already), the
>van
>> starts to slow down due to the lack of fuel slowly becoming
>unavailable
>> in the FI system. Because the fuel is used to "cool" the fuel pump,
>> running it dry can (but not always) overheat and destroy the pump.
>An
>> area to be very careful as pumps are NOT cheap.
>
> A quarter to half mile of travel won't hurt the pump...been
>there, done
>that!
> (including Sunday)
>
> Having a history of 35+ years of VW ownership including the
>first model
>('62)
> with a fuel gauge I can, anecdotally, report that NONE (zero,
>zip,
>nada) have
> exhibited "optimistic" behavior...they have all reported LESS
>fuel
>remaining
> (ie. PESSIMISTIC readings) than acually remaining in the tank!
>The
>sample
> includes: '62 112, '64.5 Porsche 356SC, '66 Westfalia, '68.5
>Bug
>w/autostick,
> '69 Westfalia, '71 Westfalia, '73 Westfalia, '75 VW-Porsche
>914 2.0,
> '81 (basic) Westfalia, '85 VanagonGL, '85 Westfalia, '86.5
>Scirocco16v,
> '91 VanagonCarat...
>
> HOWEVER, EMPTY, as beyond the RESERVE (or "red zone") or
>almost pegged
>is
> pretty much fumes remaining in the tank.
>
> The ONLY exception is the current '91 Westy under discussion.
>In
>otherwords,
> the behavior of the fuel gauge is decidedly NOT normal!
>>
>> Don't always trust the gauge. I use the odometer and the gauge as a
>team
>> to keep track of the fuel and of course the mileage I'm getting as
>well.
>> I always fill up between the 1/4 to 1/2 mark.
>
> Yep...and I said as much in my original post. I ALWAYS reset
>the trip
>odo on
> fill-up and note the mileage.
>>
>> I might add that the fuel gauges in my 84 Westy, 62 Bug and the
>following
>> formerly owned VW's have always been "optimistic" and never that
>> accurate: 67 Bus, 63 Kombi, 69 Camper, 71 9 Passenger Bus, 64
>Notchback,
>> 73 Panel Bus, 61 Panel Bus (Retrofitted with factory gauge/sender
>[new] -
>> recently seen in Hot VW's now owned by Scott Pearson/WCM), 81 Rabbit
>PU
>> Diesel, 63 Bug, 73 Karmann Ghia (bought that new) and a 59 Euro
>Single
>> Cab PU.
>
> I think you have to learn the definition of "optimistic"...
>>
>> My 73 Toyota PU and 78 "Cheby" Monte Carlo are VERY accurate.
>
> I have more anecdotal evidence with other car makes which
>refutes the
>idea
> of "accurate"...
>>
>> I'm going to acquire a 90 VW Fox Wagon this week (VERY low miles,
>fully
>> loaded). It will be interesting to see how accurate the gauge is on
>it's
>> trip from LA to Redding.
>>
>> My experience has been that the term - fuel gauge accuracy - in
>> Volkswagens is an oxymoron.
>
> That depends on how you view it...I'll bet that *most* auto
>manufacturers bias
> their fuel gauges to be pessimistic as opposed to optimistic
>or
>accurate to
> combat the tendency of the average owner to "streeeeetch" the
>time
>between
> fill-ups.
>
> I'll bet it's the voltage stabilizer.
>
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