Fuel gauge calibration - FIXED!! Page 2

Just when I thought I'd got every job done on my car, I just remembered my fuel gauge is out (well I think it is cos when my light comes on I've still 4 gallon in the tank). I know that these things can be out and need recalibrating by Porsche. The method being: Empty the fuel tank, e.g. see Checking quantity delivered by fuel system. 1. Fill the fuel tank with 28 litres of fuel, metered by volume. 2. Wait for a short time to allow the tank sensor to settle down to the level. 3. Connect the Porsche System Tester to the vehicle and start the System Tester. Switch on the ignition. >> Continue. 4. Select vehicle type, then go to the list of control units. 5. Select Instrument cluster control unit, then press >>. 6. Select the Special functions menu, then press >>. 7. Select the Tank check menu, then press >>. 8. Carry out the tank calibration; the tester gives a reading in litres, which is then synchronised to 28 litres. 9. Check position of tank needle in instrument cluster. Tank needle in lower third. 10. Fill vehicle with fuel and check position of tank needle in instrument cluster. Wait for a few minutes. Tank needle shows full. My questions are: Does anyone know if their is a recall for this and I get it done FOC? If not, anyone know the cost? Other that OPC doing this process, does anyone know of an alternative - including DIY methods? Any comments welcome!

Bump.

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Are you sure you actually have a problem? Lots of previous threads from years ago talked about the C4 having a 'saddle' type fuel tank due to limited space and so my understanding is its often got more fuel than it thinks. You need to brim it rather than 1/2 fill. Just my 2p...

Hi, I'm perfectly aware of the saddle tank that only registers after putting a third of a tank in (as I found out once after putting £20 and nearly complaining to the garage about their pumps). No, it's definitely out. Once my light comes on I can do over 100 miles and still not run out. Light usually comes on about 210 - 220 miles from brimming it. If I fill up as soon as the light comes on I get about 10 gallon in.

The gauge on my 996.2 C4 never worked properly. It would never register more than 2/3 full so I always used my trip meter as a petrol mileage recorder and zeroed it every time I filled up, normally every 250 miles. The gauge was always accurate for the last 100 miles so I never got caught out. It was a pain but I was told it would take about 3 hours to sort out the issue so I just lived with it. It was only after my WMS warranty expired that I realised I could probably have claimed for it.

When my light comes on and I fill up the most I have ever put in is 49 litres so have plenty left and this comes around 240 miles. Never worried after reading previous post about C4 tanks. Never had a problem with the tank registering full after filling up and I always wait till the fuel light comes on.

Same here, but it's a bit annoying that the light comes on when it's only used just over 2/3rds of a tank, especially if you're doing a 1000 mile journey.

I agree, I feel I should see how far I can go, but haven't got the balls to try it just incase I run out of fuel

A small square of insulating tape over the light will ease your annoyance, but not sure if pulling the tank put and fitting new innards would be worth the expenditure. Depends ultimately on how much it irritates you.

I was thinking more of something like: Run the car till it's bone dry. Disconnect the battery for 6 hours. Reconnect and brim the tank. or Connect a decent code reader and select reset fuel gauge when you've got exactly 28 litres in the tank. or There was a recall on this, call you local OPC and they'll book it in to do the reset and give you a 991 for the day whilst they carry out the work. :driving: I know that it's not a case of doing anything with the tank to make it right and was probably wrong by the dealer I bought it off letting the battery go flat with less than a 3rd of a tank in.

Well that's weird!! I've just been to fill up at my local Tesco (£1.11/litre for 99 ron with my points off :lol: ) and I reckoned I had just under a gallon left in the tank. I brimmed it right to the top (managed to get 60 litres in) and had left my ignition switched on, just to see if it made a difference to the gauge. Anyway, when I get back in, the needle is way past full (about 1/8th of a tank over the top mark). I've never seen it like this before when I've filled it, so took a quick snap (see below). Anyway I drove away from the pump and within 50 yards had to stop for something else and turned the ignition off. When I restarted the car, the fuel gauge has now dropped to the top mark (as usual). I nearly thought for a minute when the gauge shot up that it had corrected itself. :?:

I have to agree with you that it is really annoying. Wonky fuel gauges have always bothered me, years ago most cars had gauges that went up and down when you went round corners, so you had to guess how much you had left. I've been a biker since I was 16, so I've tended to go to the number of miles then fill up way of fuelling up, resetting the trip every fill up. I've just finished building a project bike which has a massive tank ( 40ltr+), so I don't yet know when the fill up point is, but I do have reserve taps so when it starts to splutter, I know I have a gallon to play with when I activate reserve. Is there a fault with the sender unit? Or has the float or float lever come loose?.

I think it just needs recalibrating by Porsche. Don't actually think there's an issue with anything, just lost it's original memory.

How come your digital speed reading is in the rev counter? My 2002 996T has it in the speedo, which is rubbish.