Fuel Distance/Mileage Module: Description and Operation

DESCRIPTION
The fuel computer calculates and displays trip distance, fuel remaining, instantaneous economy, average economy, and distance to empty. The fuel computer display consists of the fuel gauge, three digits with a decimal point, the legends LITERS/100 km and MILES/GAL, and the menu functions TRIP DISTANCE, FUEL REMAINING, INSTANT ECONOMY, AVERAGE ECONOMY, and DISTANCE TO EMPTY.

OPERATION
The fuel computer takes in signals from the speed sensor, fuel sender and the EEC-IV module. Speed information comes from the transmission-mounted speed sensor to the speedometer module, which in turn feeds the fuel computer. Fuel level information comes from the fuel sender which is located in the fuel tank, and the fuel flow information comes from the EEC-IV module.

The fuel computer goes through prove-out when powered up and then goes into normal mode by displaying the function selected before the last ignition switch turn off. All menu functions remain illuminated for three seconds following prove out, and the pointer preceding the selected function is also illuminated. After three seconds, the pointer and the non-selected functions will not be displayed. If the cluster memory has been reset by interrupting battery power to the cluster, the default display is TRIP DISTANCE.

Three of the four buttons on the switch module are used to operate the fuel computer functions. They are as follows:

- SELECT: Will move the menu cursor from top to bottom. The selected function is indicated by the position of the pointer.
- e/m: will alternately cause the fuel computer information to be displayed in English or Metric units with successive depressions.
- RESET: Will reset the TRIP DISTANCE and AVERAGE ECONOMY functions when they are selected. Two successive depressions of the RESET button within two seconds will reset both of these functions regardless of the function currently selected. No other function can be reset.

FUNCTIONS
Each of the following functions may be selected by pressing the SELECT button on the switch module until the pointer preceding the desired function is illuminated. The appropriate numeric information is displayed with units in the three digit display above the menu.

Trip Distance
Trip distance is the distance traveled in tenths of kilometers or (miles) up to 99.0 (whole numbers above 99.9) since the Trip Distance was last reset. The value is displayed with leading zeros suppressed. The value rolls over to 0.0 after 999 Kilometers or Miles. The appropriate Km or MILES logo is displayed when Trip Distance is selected. Trip Distance can be reset to 0.0 by pressing the RESET button while Trip Distance is selected.

Fuel Remaining
Fuel Remaining is the amount of fuel remaining in the tank. The fuel remaining value will be consistent with the display of the FUEL bargraph segments. It is displayed in whole liters or gallons along with the LITERS or GAL logo. The numeric range of the fuel remaining display is from 66 liters (17 gallons) down to 3 liters (1 gallon). The value "F" (Full) is displayed above 66 liters (17 gallons) and "E" (Empty) is displayed below 3 liters (1 gallon). Fuel remaining cannot be reset.

Instantaneous Fuel Economy
Instant economy is the fuel economy calculated at that instant. The instantaneous fuel economy value is displayed along with the LITERS /100 km or MILES/GAL logo. The range of Instant Economy which can be displayed is from 99 to 0 LITERS /100 km or from 0 to 99 MILES 1 GAL. When the vehicle is not moving, Instant Economy is displayed as 99.9 to 0.0 LITERS/100 km or 0.0 to 99.9 MILES/GAL. Instantaneous Fuel Economy cannot be reset.

Average Fuel Economy
Average economy is the fuel economy obtained since the Average Economy function was last reset. The average fuel economy value is displayed along with the LITERS I 100 km or MILES/GAL logo. The range of average economy which can be displayed is from 99.9 to 0.0 LITERS/ 100 km (0.0 to 99.9 MILES/ GAL). Average economy can be reset by pressing the RESET button while Average Economy is displayed. A reset causes the current instantaneous fuel economy value to be displayed as the average fuel economy. This value is then updated according to continuing changes in vehicle speed and fuel consumption.

Distance To Empty
Distance To Empty (DTE) is the distance that can be traveled before the fuel tank becomes empty. The Distance To Empty value is displayed in whole kilometers or miles along with the km or MILES logo. The range of distance to empty which can be displayed is from 0 to 999 kilometers or miles. Distance to empty cannot be reset.

Low DTE Alert
At 80 km (50 miles) to empty, the fuel computer self selects the Distance To Empty function, provides a one second audible tone, and flashes the DTE value for approximately five seconds. The display continues to indicate DTE (not flashing) until another function is selected. This alert will reoccur at 40 Km (25 miles) and at 16 Km (10 miles) to empty and at every subsequent power up below 80 Km (50 miles) to empty.