Question on Gas Tank Indicator

Last few times when i gas, it seems like it is full and i'm not able to put anymore gas in, but for some reason the gas indicator in the car still shows about 1/8 below the full line. I gas when light comes on and take in about 13 to 13.5 gallons. Just curious as to whether anyone has had this problem, and whether its a gas indicator issue. Or is it related to my installing the PSS9 which adjusts ride height and prevents me from filling up the gas tank. Thanks

I have intermittent problems getting a full tank of gas in the car. Occasionally, the pump will shut off and I'll get a 3/4 tank of gas. It happens at different stations so I don't think it's a pump issue. I got a full tank in yesterday. My service rep has never heard of a failure of the gas indicator. Is it a problem with the design of the filler neck, allowing pressure (gasoline fumes, air?) to build up and trigger the pump to shut off? I have made it a habit to check my fuel level after my fill-ups so I don't get stuck, thumbing a ride at the roadside.

I have the same problem. I've been told by other Porsche owners that it's a software problem. The dealer can correct it.

Ok thanks, I'll check with dealer

This was also a problem with early C4s. If you ran the car until the gas light came on, when you tried to refill it would only show 2/3 full. I believe there was a recall on this.

i had this, still have it. '04 C4S. Dealer checked and mine wasn't part of the recall, but they replaced the fuel sending pump anyways. Still no change - refueling sometimes hits me all the way to full tank, sometimes to 3/4 to 7/8. I've tried refueling before reserve light goes on, after, from 1/2 a tank, etc. No real change.

There is new TSB out about this (only for MY02 and newer cars). Ask your dealer to perform TSB 1/04 2066 Incorrect Fuel Level Display in Instrument Cluster (dated 3-26-04). It will take them at least 2-3 hours to fix the problem (according to the TSB). The fuel pump is not the problem. The float sensor is catching on one of the fuel lines. They need to go into the tank reroute the lines and use a tie-wraps to secure the lines.

Loren, thanks for the information!

Thanks Loren. I have an 03 C4S and hadn't taken it in yet. I will now. Great help!!

there was a recall on the fuel sending unit in my car. once it was replaced, it worked fine. in my case the gas gauge got stuck on empty!

This is exactly what's been going on with mine. 2 sending units later and still no change. I'm tired of bitching about it! Every once in a while it may show "FULL" but mostly it's 3/4 to 7/8.

Maybe Porsche is using the same standards of fuel gauge calibration that the FAA uses on general aviation planes - the gauges only have to be accurate at empty. Steve 99 996 79 Cessna 152

I also have had an intermittent fueling issue with my 2004 C4S. I fill the tank, sometimes before and sometimes after the fuel indicator light comes on. On occasion, the pump would shut off and the gauge would read about 3/4 or 7/8. I didn't try to top-off, because my first fill resulted in some spillage when I tried to squeeze in that last 0.1-0.2 gal. Thinking that there might be a gas pump problem, I then tried 3 or 4 different stations. Well, the filling problem persisted, so I took the car into my local Porsche dealer. They couldn't find a problem, and suggested that I bring it in when the regional service rep was at the shop. The next time I left the car and the agency replaced the fuel tank because they said the sensor might be bad and it could not be replaced separately from the tank.. I was told that Porsche Technical in Atlanta also advised them to replace the ORVR (?) valve. My car was at the dealer for a week on that visit. The dealer filled the tank and everything seemed to be o.k., until last week when I refilled. Guess what? The pump shut off and the gauge showed a little more than 3/4. I calculate milage between tanks, and the value for that tank was impossible. I called the local dealer and mentioned some of the comments on this forum, including the TSB referenced above. The service manager was quite sure the TSB was addressed, and that was not the problem with my car. I now have an appointment to take my car in next week when the regional service manager will again be on site. This whole thing is getting quite frustrating, because I have a recurring problem that is not being fixed! Any suggestions would be appreciated....

lOl nickS nice avatar

My experience has been that if I fill the tank with the nozzle flowing at the highest rate, when it shuts off automatically I can still put as much as 2.5 to 3 more gallons in at a drastically slower rate before the fuel level reaches the vicinity of the filler neck on the car. If I accept the initial shutoff as final and don't put in any more fuel, the gauge typically reads about 7/8 ths, which would be about right for 13 or 14 gallons in a 16.9 gallon tank. If you fill at max flow and don't top off I would expect you'd see the gauge reading not full. The gauge in my car is right on from what I've seen. The design of fuel storage system on the 996 doesn't seem to lend itself to topping off the car without a lot of short squirts. By contrast, when our Acura MDX is being filled and the nozzle shuts off, the car is within about a pint from being topped off.