Re:low fuel signal (was: computer MPG adjustment)

[pjrose@servtech.com (Phil & Judy Rose)]

>> This thread is to address the question of _instrument panel_ adjustment of
>> MPG output. All I had originally posted was the simple fact (heh, heh) that
>> when the MPG adjustment in the instrument panel is done (+15% to -15%
>> range), one needs to keep in mind that what this does is to change the
>> "fuel consumption factor" (up or down) and therefore has the _inverse_
>> effect on the MPG readout. If MPG reads too low, then decrease the FCF (and
>> vice versa).
>
>Is this done using the set of DIP switches at the back of the
>instrument cluster? If yes, then do these switches also control the
>level at which the "out of fuel" indicator on the auto-check system
>will be displayed? Mine pops up at above 1/3 tank left. The
>consumption figures and raneg left and fuel level gauge work perfectly
>fine.
>

Yes, the FCF refers to the DIP switches at the back. To my knowledge (i.e.,
my Bentley knowledge, that is), these switches should not affect the
low-fuel level warning from the Autocheck system. It seems that this
warning takes its info from the resistance change caused by the fuel level
sensor in the tank. In the 26-pin connector at the back of the instrument
cluster, the resistance between terminals 3 and 10 should be 40 ohms for
full tank and 283 ohms for empty tank. I suppose it's possible that the
connections have developed some extra resistance from poor contacts,
causing your Autocheck to believe the tank has less fuel than actual. So
you might try cleaning these connectors.

Phil