Fuel gauge reading incorrectly?

[woolveren]

Yesterday while driving back home the reserve light came on and I thought of filling the gas today. But when I started the car today morning, the fuel gauge needle just moved a bit from empty mark, but didn't go all the way upto the reserve mark. Also the center display was showing 0 miles with the current amount of fuel.

I was pretty sure that it went to reserve when I was only 1 mile away from home and there is no way 2 gallons of fuel can escape unless something is wrong with the tank. I then went to a nearby gas station and filled 3 gallons of gas, then the needle showed the right amount of fuel. This is the first time am observing this behavior of the fuel gauge.

Does this has something to do with the outside temperature? Today the temperature was 25 degree F when i started car in morning. Temperature here went as low as 8 degree F during last month. Also, I know that there is whining sound coming from the fuel pump, probably its going bad. Does any of these can affect the guage working?

Car is a 98 a4 1.8T with 250K miles.

[giorgos_B5c]

Same thing here...I can never get a right reading unless i park on a dead flat road.If i park with the car pointing upwards it goes empty.If i park with the car pointing downwards....It fills up

[woolveren]

Same thing here...I can never get a right reading unless i park on a dead flat road.If i park with the car pointing upwards it goes empty.If i park with the car pointing downwards....It fills up

Mine does read correctly now. This was like a one time thing that just happened today for the first time.

So if I get some input on what's going bad, then I can start looking for those parts before this gets more worse.

[k0mpresd]

the fuel level senders are pretty bad about crapping out. cheap and easy to replace.

[SGS]

The amount of fuel does directly deal with the outside ambient tempature. Fuel will be thicker with lower tempature and thiner at higher tempature. Molecules expand and contrast with heat added/taken away. But your fuel level will not jump drastically. The only thing that will do that as stated before is the incline of the road your on. Just from what I perfer though and I know in diesels and jet engines it is bad to run a motor out of gas because the sediments settle at the bottom of the tank and when your sucking up fumes you are also sucking up those sediments that have been at the bottom of your tank since the car came off the production line...

[Tanzimur]

The amount of fuel does directly deal with the outside ambient tempature. Fuel will be thicker with lower tempature and thiner at higher tempature. Molecules expand and contrast with heat added/taken away. But your fuel level will not jump drastically. The only thing that will do that as stated before is the incline of the road your on. Just from what I perfer though and I know in diesels and jet engines it is bad to run a motor out of gas because the sediments settle at the bottom of the tank and when your sucking up fumes you are also sucking up those sediments that have been at the bottom of your tank since the car came off the production line...

Or signs of a fuel pump on its way out lol keep your tanks filled above a qrtr tank always to prevent that

[JAM3S121]

I previously had a dead fuel sender and replaced it with one from a s4 that had 75k miles.. my gauage never correctly read the fuel level. I would start my car and it would read less fuel then what is really in the car.

In the morning start my car, it would read a few notches less than 1/2 fuel then if I let the car idle for 5minutes the gauge would slowly go back over the middle.. perhaps it is the tempature. Of the 2 cars I've ever owned (my b5 and my grand am) the gas gauges did not work so I'm not used too what would be normal. The one I replaced in my b5 shortly died and I just estimate my mileage again with the trip meter...

[woolveren]

Or signs of a fuel pump on its way out lol keep your tanks filled above a qrtr tank always to prevent that

How can I replace it? Any DIY's available?

the fuel level senders are pretty bad about crapping out. cheap and easy to replace.

As I said above, there is a high pitch whining noise coming from the rear seat area and am pretty sure that it's the fuel pump. If I remember correctly, this whining noise was there for the last 1 year but didn't affect any performance yet. I still get around 25miles/gallon.

So you think this gauge issue happened because of my car's faulty pump?

[Tanzimur]

I couldnt find any DIY's but simply drive the car till your almost empty so itll be easy to drop the gas tank from the car and you open it up and theres the fuel pump

[Avant Nate]

Wait until near empty tank, no need to drop the tank.
http://www.audizine.com/forum/showth...l-sending-unit