Gas tank content

[docdav]

Strange strange???

I normally fill up the tank when the light comes on. It takes max 32 liters and the manual says it should take about 60 liters. After having filled (with the 32 liters) the meter shows full tank. When driving nicely, the car goes about 10 km/l thats ok. Range on a full tank (untill the light comes on is about 290 km

 

The tank seems too small.?

 

Any suggestions?

 

Its a C4

 

Kind regards Michael

Edited November 16, 2014 by docdav

[JFP in PA]

Strange strange???

I normally fill up the tank when the light comes on. It takes max 32 liters and the manual says it should take about 60 liters. After having filled (with the 32 liters) the meter shows full tank. When driving nicely, the car goes about 10 km/l thats ok. Range on a full tank (untill the light comes on is about 290 km

 

The tank seems too small.?

 

Any suggestions?

 

Its a C4

 

Kind regards Michael

 

A C4 should hold about 64L of fuel total, it is possible that your gauge is not calibrated correctly as you should be down more that half a tank when the light comes on.

[Loren]

Here is the difference in your tank (C4, C4S, and Turbo)

 

You tank actually looks like this (note the lower area where the level gauge does not go.

 

Here is what Porsche says in a TSB about "running out of fuel..."

In all current models except the 911 Carrera 4 (996), the fuel level warning
light (reserve) illuminates when there is approx. 10 liters of fuel remaining in the fuel tank.
When the reserve light comes on, the driving-distance-on-remaining-fuel (trip computer) is calculated by
monitoring the fuel consumption signal (ti), and continues until the fuel tank is empty (or refilled).

In the case of the 911 Carrera 4 (996), the shape and configuration of the fuel tank prevent the fuel
level sensing system from being able to physically read down to a level of 10 liters. Therefore, on the
911 Carrera 4 the driving-distance-on-remaining-fuel calculation begins when the fuel reaches a level of
19 liters (approx. 1/4 tank).

As fuel is further consumed below 19 liters, the amount of fuel remaining in the tank is a calculated
value. The calculated value is derived from the fuel consumption signal (ti), and continues until the fuel
tank is empty (unless the fuel tank is refilled).

Whenever the fuel level is less than 19 liters and the ignition is switched off, the fuel-level and driving-distance-
on-remaining-fuel values are stored in instrument cluster memory.

If battery power is interrupted, these stored values are lost (erased from instrument cluster memory).
Once lost, these values will not be automatically recalculated unless the fuel tank is filled with at least
19 liters (crossing the calculation-switchover threshold).

To summarize, if the battery is disconnected with the fuel level less than 1/4 tank, the fuel level and driving-
range-on-remaining-fuel values will be incorrect. When the battery is reconnected, the fuel
calculation will default to 19 liters, when in fact, the fuel level is most likely less than 19 liters. This can
result in the vehicle running out of fuel, with a seemingly good fuel level indication.

If the battery must be disconnected on a 911 Carrera 4 (996), perform one of the following to prevent
running out of fuel:
1. Fill the fuel tank with more than 19 liters of fuel (1/4 or more) before disconnecting the battery. This
will eliminate the danger of invalid values being stored because the fuel level will already be above the
calculation switching point when the battery is reconnected.
or
2. Fill the fuel tank with at least 19 liters of fuel after reconnecting the battery. This will reset the calculation
process with valid values.

Of course our Contributing Members have access to all the TSBs as well as many other technical documents.

 

[docdav]

True friends. I have looked at pictures of the sender, it looks like it is pressed to the bottom by a spring, and there is a telescopic mecanism in the unit itself, There must be theoretical risk og the telescopic mecanism has got stucked in a high position and the foot of the unit is not at the bottom? Just a thought (and a easy check). But the above also makes sense.

 

Thank you for responses.

 

Michael