Fuel gauge stays on 3/4 of a tank with ignition on, and when ignition is off it reads 1/4 of a tank all the time. it is a 2005 flhtielectra glide standard.if anyone knows what is wrong i would be grateful thank u

if you have 2 fuel gauges working of a tank switch there may be some resistance in the circuit of the second circuit that increases the reading of the gauge. Personally I have the tanks balanced out with a levelling hose between them the the gauge reads the capacity left in the tanks IE full-- both tanks-- full, 1/2 both tanks 1/2 With the way you have it set up then if one gauge is faulty and shows full when it is empty you can find yourself in a spot of bother when you need the other tank

Check for 12 volts at the orange wire on the fuel gauge. If missing check instrument fuse and associated wiring. If present do the following checks:

1. Remove gauge. Ground Y/W wire of fuel gauge sender located at bottom of gauge. Turn ignition switch ON.

a. Fuel gauge must indicate FULL. If gauge indicated FULL, gauge is functioning correctly and go to step 2.

b. If gauge did not indicate FULL, proceed to step 3.

2. Set MULTI-METER to resistance scale to measure the resistance of the sending unit. Place one probe on Y/W and the other probe on a good ground.

a. If fuel tank is full, the reading should be 40 ohms. An empty tank should have a 240 ohm resistance. A half full tank will be pproximately 97-118 ohms.

b. If a very high resistance or infinity is indicated on the meter, the sender may be "open" or not grounded. Check that sender and fuel tank are grounded by placing one probe of Multi-Meter on sender ****** and the other probe on crankcase. Meter must indicate one ohm or less. Replace sender if one ohm or less was present. If a higher resistance is present, check for poor connection on ground wire.

WHAT DTC\'s are set???



It sounds like a short to ground on the gauge circuit but see below for further and better diagnosis:



When the ignition switch is ON the fuel gauge is connected to 12 VDC, current flows through the gauge and the variable resistor in the fuel gauge sending unit to ground. The sending unit float controls the amount of resistance in the variable resistor. Malfunctioning fuel gauges may be the result of a fuel gauge sender or a fuel gauge not being properly grounded OR there may be a defect in the fuel gauge sender or in the fuel gauge itself OR there may be an open circuit caused by a loose or disconnected connection or a broken wire between the ignition switch to the fuel gauge.



A suspect fuel gauge system can be tested by FIRST removing the gauge and grounding the Y/W wire of the fuel gauge sender located at the bottom of the gauge, turning the ignition switch ON at which point the fuel gauge must indicate FULL. And if it does so then the fuel gauge is functioning correctly.And if it does not read FULL then get a multimeter set to the RX1 scale and measure the resistance of the sending unit by placing one of the meter probes on the Y/W wire and the other probe on a good ground. THEN for FLHT/C/U, FLTR if thefuel tank is full the meter reading should be 7-14 ohms and if the tank is empty the meter resistance reading should be 74-95 ohms resistance and a half full tank meter resistance reading will be approximately 30-38 ohms. For FLHR/C/S if the fuel tank is full, the meter resistance reading should be 27-40 ohms, if the tank is empty 240-264 ohms and if half full approximately 97-118 ohms. FOR ALL MODELS if there is a very high meter resistance or infinity reading the sender may be "open" or not grounded. In this case check to see if the sender and fuel tank are grounded by placing one of the ohmmeter probes on the flange of the sender and the other probe on crankcase and if the ground is good the meter must indicate one ohm or less and if the reading is one ohm or less the sender is defective and requires replacement and if a higher resistance reading is obtained you will need to check for a poor ground wire. THEN you can check the voltage to the O/W (+) wire and the BK (-) wire of the fuel gauge connector if the gauge did not indicate FULL and the correct reading will depend on the source voltage and the level of fuel in the tank or the position of the sender float arm on the variable resistor etc. If there is NO battery voltage present there may be a broken, highly corroded or disconnected power wire. If you cannot find a problem using the above testing replace the gauge itself.

When the ignition switch is ON the fuel gauge is connected to 12 VDC, current flows through the gauge and the variable resistor in the fuel gauge sending unit to ground. The sending unit float controls the amount of resistance in the variable resistor. Malfunctioning fuel gauges may be the result of a fuel gauge sender or a fuel gauge not being properly grounded OR there may be a defect in the fuel gauge sender or in the fuel gauge itself OR there may be an open circuit caused by a loose or disconnected connection or a broken wire between the ignition switch to the fuel gauge.



A suspect fuel gauge system can be tested by FIRST removing the gauge and grounding the Y/W wire of the fuel gauge sender located at the bottom of the gauge, turning the ignition switch ON at which point the fuel gauge must indicate FULL. And if it does so then the fuel gauge is functioning correctly.And if it does not read FULL then get a multimeter set to the RX1 scale and measure the resistance of the sending unit by placing one of the meter probes on the Y/W wire and the other probe on a good ground. THEN for FLHT/C/U, FLTR if thefuel tank is full the meter reading should be 7-14 ohms and if the tank is empty the meter resistance reading should be 74-95 ohms resistance and a half full tank meter resistance reading will be approximately 30-38 ohms. For FLHR/C/S if the fuel tank isfull, the meter resistance reading should be 27-40 ohms, if the tank is empty 240-264 ohms and if half full approximately 97-118 ohms. FOR ALL MODELS if there is a very highmeter resistance or infinity reading the sender may be "open" or not grounded. In this case check to see if the sender and fuel tank are grounded by placing one of the ohmmeter probes on the flange of the sender and the other probe on crankcase and if the ground is good the meter must indicate one ohm or less and if the reading is one ohm or less the sender is defective and requires replacement and if a higher resistance reading is obtained you will need to check for a poor ground wire. THENyou can check the voltage to the O/W (+) wire and the BK (-) wire of the fuel gauge connector if the gauge did not indicate FULL and the correct reading will depend on the source voltage and the level of fuel in the tank or the position of the sender float arm on the variable resistor etc. If there is NO battery voltage present there may be a broken, highly corroded or disconnected power wire. If you cannot find a problem using the above testingreplace the gauge itself.

3 things to check out. Cheapest is to set your tripmeter when filling up. If this problem occurs after riding more than 180 miles, then the fuel gauge is probably reading incorrectly. Maximum range on full tank is around 200 miles. I haven't "walked for gas" since 1968. Second cheapest one is two is to add a water remover product (not fuel injector cleaner or other related product) to a full tank of gas. Make sure to measure the amount in proportion to your 5 gallon fuel tank to a car's fuel tank. The other is to take it to a qualified mechanic who can test the fuel pump pressure.

Hi you have a fuel pressure switch n the float in gas tank may be sticking

2005 PT cruiser, i replaced the cam sensor with a aft market sensor my fuel gauge started reading wrong, and it didn't fix my problem so i replaced the cam sensor with a factory sensor it fix my running problem but the fuel gauge still reads wrong, with a full tank of gas the gauge reads 3/4 tank,

The problem is caused by the fuel sloshing around in the tank and the fact that Harley does not use a "dampened" gauge. The sending unit is a float attached to a rod inside the fuel tank. As the float rises and lowers, it changes the resistance of a variable resistor in the tank. The resistance is read by the gauge and converted into a reading that approximates the level of fuel in the tank. The reason the gauge is not dampened could be any number of reasons. Either Harley wanted to use a cheap gauge or a dampened gauge might allow you to run out of fuel because it reads the level of the fuel too slowly. In small tanks like the ones on motorcycles, this could be a problem. I know of no way to remedy the problem without changing the gauge and sending unit.

Good Luck
Steve

hi will, it sounds like one or both of the fuel sending units has failed. the sender on the passenger side is responsible for reading empty to 1/2 tank, and the one on the driver's reads 1/2 to full. if the passenger sender is stuck down or failed, it could read empty when the tank is full. the senders are a pain to install correctly due to the installation angle. I have even seen techs at the dealer install them and have to reinstall them. i would recommend having both of the senders tested.