So I've had my car parked for 4-5 months. I started it a couple times throughout the winter and the fuel gauge always read fine.

So today I go put some gas in it because it's going to the shop next week for spring power ads and such.

I put 4 gallons in and the fuel gauge stayed exactly where it was before....

When I turn the car off the needle drops to zero and when I start the car again it only went up to where it was before (just above empty). And my gas light it still on.

Any ideas??

 

Unless I'm missing something, that's a common quirk of the gauge and how it operates ( or doesn't ). Try filling it until it recognizes you've filled it sufficiently for the sensor to recognize it. It's wierd and sucks when you put in a few gals and the gauge doesn't budge. Happens every time I run low and just put a couple in trying to get to optimal fuel and fill to capacity. Then the gauge responds properly.

 

You need to fill it up (or fill it up to a certain level). Basically, my understanding is that the gauge doesn't read the last portion of the tank -- it's an estimate by the computer at that point. If you just put a few gallons in, the fuel gauge won't reflect that. Besides, by the time you own a Porsche, you should be well beyond the days of putting in a few bucks worth of gas. (Of course, I realize that you might only be putting in a little bit so the full tank of gas doesn't get old).

 

The sending unit is a part that has a long and troubled history. As posted above, it's also not accurate on the lower end of the gauge. You need to fill up the tank to at least 3/4 to get it to start giving you the right reading. Of course that assumes the sending unit is still working properly. I had 3 of them go bad on my old 996.

One very easy way to break them is to leave the car running or leave the gauge powered while filling up. ALWAYS shut off your car while fueling!

 

That does make sense. I probably didn't put enough in to have it register on the gauge. I didn't want to fill it up as the gas won't be used for a month anyways.

That is a really dumb thing for porsche to do.... Oh well!

 

Fill up to the max and it will work again. I remember first time it happened to me, I went back to petrol station and accused them of cheating! Ha ha ha!

 

Yep damn right. When mine is showing totally empty; warning lamp and needle on the bottom of red marker, I still have 10 litres in the tank.

 

i did this last week. filled a cpl gals, with no visual register of the added fuel to the gauge. on the way to refill, the gauge flatlined and the digital estimate of how much fuel went from a few miles to --------- .

not what you want to see in the middle of a ten mile canyon.

 

The problem with the sensor (and the tank) is there is a hump in the tank. Basically two compartments of the tank. The sensor is in the upper portion of the tank and therefore does not read the fuel in the lower portion. As already said, the computer estimates what is there based on fuel consumption.

 

Just found out my 07 GT3 RS has the same issue. Filled it all the way until it overflowed , gauge is still at 1/4 and it went from 80 miles remaining to 50 miles today after a short drive. The tank is absolutely full.

Time me to have it checked out ?