Re: More problems

[cordeiro@adi.com (Alan Cordeiro)]

>For the last week or so I have been informed by my trip computer
>that my fuel tank is empty.  (Flashing E in the display.)  The
>fuel gauge says otherwise.  It indicates that I have maybe a
>third to perhaps a half tank left.  When I fill the tank it
>accepts only about the right amount as indicated by the fuel
>gauge.

>Driving the car for a few miles causes the computer miles
>remaining display to increase from E to 30 to 35 to 40, etc.,
>until it finally reaches some fairly realistic estimate of what
>should be correct based upon the fuel gauge reading.  The next
>morning (or evening) the process repeats again.

Hi Bob,

For starters, the transducer in the fuel tank is probably OK since your
guage seems to read correctly. So now we concentrate on the trip computer.

The "miles to empty" reading is calculated on the fly from information
based on the current fuel economy, and the fuel level in the tank.
Current fuel economy is calculated continuously ( every few seconds ) 
by reading the fuel flow sensor right next to the fuel pump and dividing
by the number of odometer pulses received between the readings. The miles
to empty is based on the PRESENT RATE OF FUEL CONSUMPTION.

I suspect some location in the trip computer's memory holds the present
average, and would be a "starting point" when you first start the car.
( This is a GUESS... who knows what they use ). If this location were
reset to zero MPG somehow, no matter how full your tank was, you would
have ZERO miles to empty. Then as the MPG climbs upward, the miles to
empty would recover.

I'm not sure what the solution could be .... but try and look at the
fuel economy averages when you first start. Then while you drive
run the display with the average displayed. Keep resetting it from
time to time and you will see the "instantaneous average" as it were.

Perhaps you have a problem with the fuel flow sensor, and this is
creating the strange behaviour.

Alan Cordeiro