Interpreting the Fuel Gauge

Tank Capacities

Tank	Liters	US Gallons	Imperial Gallons	Sensor
Upper	20.80	5.50	4.57	Float/sender
Lower	8.20	2.17	1.81	Thermistor
Total	29.00	7.67	6.38

The fuel pump and sensor assemblies occupy a small amount of the tank's volume. The largest reported fill-up is 27.63 liters (7.3 US gallons, 6.08 Imperial gallons). Figure reported in US gallons.

Filling on the center stand will get more fuel into the tank. Some prefer to fill on the side stand because the extra range is not as critical and it prevents overfilling, which will permanently damage the evaporation canister.

Normal Indications

Three or More Bars

There is still fuel in the upper tank.

Two Bars

The float in the upper tank has bottomed out. There is still a small amount of fuel remaining in the upper tank.

One Flashing Bar and Estimated Remaining Range

The upper tank and the hose connecting it to the lower tank are empty. The thermistor in the lower tank has been exposed to air and the computer has estimated that there are are 5 liters (1.32 US gallons, 1.10 Imperial gallons) remaining. The fuel consumption display switches to Estimated Remaining Range (ERR).

Below this point, there are no other sensors in the fuel tank and the trip computer will calculate the Estimated Remaining Fuel (ERF) by monitoring the pulses the Engine Control Module (ECM) sends to trigger the fuel injectors. This method is not considered very accurate.

ERR is continuously calculated based upon ERF and the average fuel consumption during the last 20 minutes of riding. This means that if the 20 minutes prior to reaching this point were spent riding downhill, the ERR will be greater than if the same time was spent in city traffic. A change in riding style or conditions while on reserve will precipitate a change in the ERR as it starts to have larger effect on on the average MPG during the 20-minute window.

Treat ERR as you would the fuel reserve switch. Treating the ERR as accurate is likely to result in running out of fuel. To make the most use of the fuel in the lower tank, monitor the trip odometer instead.

Differences in riding style (freeway vs. rural or stop-and-go) can cause fuel to slosh around in the tank and cause the sensors in either tank to provide incorrect readings.

ERF and ERR are retained when the ignition is turned off. Removing battery power will reset ERF and ERR.

One Flashing Bar and ERR Showing --.-

The computer has estimated that there are 2 liters (0.5 US gallons, 0.44 imperial gallons) remaining and can no longer estimate ERR.

Fuel in the lower tank is used to cool the fuel pump. A completely dry lower tank may cause the fuel pump to overheat and fail.

Error Condition Indications

All segments and --.- blinking

Upper tank sensor:

• Open or short circuit
• Faulty sensor

Lower tank sensor:

• Short circuit
• Faulty sensor

Faulty gauge panel.

All segments normal and --.- blinking

Open or short circuit in the fuel pulse line.

Faulty ECM.

Faulty gauge panel.

Reference

Related Pages

• Calibrate Your Fuel Gauge (for ST1100): http://www.pan-europe.utvinternet.ie/guides/recalibrate_your_fuel_gauge.htm

Sources

• OwnersManual
• Service Manual, page 22-17

-- MarkFeit - 23 Sep 2005