Petrol Gauge - Incorrect Reading

[Hombre]

Guys,

I have noticed that if I let the petrol gauge go below last quarter line I encounter problems.

i.e. I was on red warning light with about 42Kms left of juice. I re-fueled putting in half-tank worth of petrol. The gauge did not move and read "red". Dash still suggested 42Kms left also.

I went back next day and filled tank to brim. Gauge went back to registering Full "4/4".

Is this common on 996?

[fastboydave]

Guys,

I have noticed that if I let the petrol gauge go below last quarter line I encounter problems.

i.e. I was on red warning light with about 42Kms left of juice. I re-fueled putting in half-tank worth of petrol. The gauge did not move and read "red". Dash still suggested 42Kms left also.

I went back next day and filled tank to brim. Gauge went back to registering Full "4/4".

Is this common on 996?

I had the exact same problem on a brand new (at the time) Boxster S. After filling the tank up fully, the problem went away and never came back. It was as if running the tank 'low', something got stuck as it was tight/new??? Dont know??

[Philip1972]

It is a common issue. Sometimes, if its run very low, you have to put a certain amount in before it will register on the gague. If I run mine till the light comes on I have to put more than £25 in before it registers. I have no idea why?

[Richard Hamilton]

There are a couple of TSB's about this. I think you should take a look at them.

[Loren]

Only C4 has a problem with this - it is even noted in the Owners manual.

The C4 has a "saddle bag" fuel tank - that is, part of the tank sits on each side of the front wheel drive axle. So the fuel level sender is only on one side and it does not know how much gas is on the other side - it guesses. So if you let the tank get too low it can get confused.

The easy fix is to always fill the tank as it reaches the 1/4 mark.

[Hombre]

Loren,

Many thanks that makes complete sense.

[Richard Hamilton]

On the Boxster there is a TSB (1/04) for the same problem that involves re-routing the fuel pressure pipe in the fuel tank. There is a similar one for the 996 (5/99).

[SteveGraham]

I have a 2005 996 TTS and experience the same thing. So, does the TTS also have a "saddlebag" gas tank like the C4, or just the C4, and I'm experiencing a difference issue?

Again, once filled to 4/4 fuel gauge reads correctly.

Also, if the TTS has a "saddlebag" fuel tank, is its fuel capacity reduced from a "standard" fuel tank. It just seems like I can't put much fuel in the thing when the low fuel light comes on (about 10 US gallons).

TIA, Steve

[Loren]

The fuel tank used on the C4/C4S/TT and TTS are the same.

A C2 holds 16.9 gallons/64 liters.

C4/C4S/TT/TTS holds 16.6 gallons/63 liters.