V8V inaccurate fuel gauge
Discussion
I hate the anxiety of running low on fuel, especially in a car like the Vantage, where a little fuel doesn't get you very far. Getting low in deepest Wales or Scotland is a recipe for an AA callout...
I generally fill up soon after the low fuel light comes on, but on occasion, I've run it towards the bottom of the gauge waiting for a filling station with 99 octane fuel, before finally bottling it and filling up with 95. By this point, the remaining range on the dash display has usually dropped to zero
However, I've just checked my Fuelly record (60+ fills, 12,500 miles, average 20.0mpg) and the most I've ever put in is 58 litres. According to the manual, the tank has a usable capacity of 78 litres, so it looks like I'm filling up well before I need to (c. 60-80 miles too early),
Does anyone ignore the gauge and wait longer, or do you chicken out too?
I generally fill up soon after the low fuel light comes on, but on occasion, I've run it towards the bottom of the gauge waiting for a filling station with 99 octane fuel, before finally bottling it and filling up with 95. By this point, the remaining range on the dash display has usually dropped to zero
However, I've just checked my Fuelly record (60+ fills, 12,500 miles, average 20.0mpg) and the most I've ever put in is 58 litres. According to the manual, the tank has a usable capacity of 78 litres, so it looks like I'm filling up well before I need to (c. 60-80 miles too early),
Does anyone ignore the gauge and wait longer, or do you chicken out too?
Nigel_O said:
<snip>
Does anyone ignore the gauge and wait longer, or do you chicken out too?
I never wait for the fuel light and usually refill at around or below 1/4. On my 4.7 V8V the gauge is slightly non-linear and it seems to have less than half a tank at the half mark. I usually bank on adding about 60 litres.Does anyone ignore the gauge and wait longer, or do you chicken out too?
I don’t ignore the fuel gage in the 4.7 V8V.
It drops like a stone in the last quarter, especially in kph in France. Did get down 12km range after 20 minutes of slowish driving and minimal acceleration on motorway back towards Rouen after Le Mans as was surprised at the long gap after a few service stations every 20km or so. Not keen on autoroute service station prices and also didn’t want to re-overtake lots of cars. Finally pulled into unmanned petrol pumps (but they were out of order) and other guys at pumps found a sleepy village 5 miles or so with a Total Energies station open on the Monday. Read just 6km after starting up at motorway filling station ti head off into the country.
Have run out at least 5 times in other cars - last time in Jaguar with large engine and still showed 9 miles range and didn’t make it to Shell station 1/2 a mile away. Also once got a Discovery stuck diagonally across the road as tried to turn right into another local station many years ago - took a few people to push that. Audi TT Mk 1’s are also surprisingly heavy - 200m short that time.
Jag was last time. No longer run zero plus 20 miles as starting up from cold burns so much fuel.
Try to only use Esso Supreme in UK for the Vantage and as that’s a 10 to 15 min drive away on a busy road so normally refill at a quarter.
It drops like a stone in the last quarter, especially in kph in France. Did get down 12km range after 20 minutes of slowish driving and minimal acceleration on motorway back towards Rouen after Le Mans as was surprised at the long gap after a few service stations every 20km or so. Not keen on autoroute service station prices and also didn’t want to re-overtake lots of cars. Finally pulled into unmanned petrol pumps (but they were out of order) and other guys at pumps found a sleepy village 5 miles or so with a Total Energies station open on the Monday. Read just 6km after starting up at motorway filling station ti head off into the country.
Have run out at least 5 times in other cars - last time in Jaguar with large engine and still showed 9 miles range and didn’t make it to Shell station 1/2 a mile away. Also once got a Discovery stuck diagonally across the road as tried to turn right into another local station many years ago - took a few people to push that. Audi TT Mk 1’s are also surprisingly heavy - 200m short that time.
Jag was last time. No longer run zero plus 20 miles as starting up from cold burns so much fuel.
Try to only use Esso Supreme in UK for the Vantage and as that’s a 10 to 15 min drive away on a busy road so normally refill at a quarter.
I really don’t understand why anyone would intentionally wait until the low fuel light illuminates before they decide to refuel, especially when you say you hate the anxiety of running low. That makes absolutely no sense at all. I hope you’re not a pilot too! I am firmly aligned with LTP on this issue. BRM.
2007 4.3 here, I do find the gauge pretty accurate (actually both in this car and the 2008 I had previously) and I tend not to fill up before I need to, as the gauge has been accurate. I'm sure I've had 78 litres on a fill before so you should be getting more. The tank size is actually a huge plus for me as if you're on a long trip it's easy to get 400+ miles range.
Stupid question but I assume that your gauge needle at full is fully round at the top? I find some fuels are frothier and cause the pump cut out to kick in prematurely, sometimes it can be the angle of dangle of the pump into the filler neck that exacerbates it. This happened recently to me in France, thought it was full but when I got in the car it was 5-10 litres short of full.
Stupid question but I assume that your gauge needle at full is fully round at the top? I find some fuels are frothier and cause the pump cut out to kick in prematurely, sometimes it can be the angle of dangle of the pump into the filler neck that exacerbates it. This happened recently to me in France, thought it was full but when I got in the car it was 5-10 litres short of full.
olv said:
2007 4.3 here, I do find the gauge pretty accurate (actually both in this car and the 2008 I had previously) and I tend not to fill up before I need to, as the gauge has been accurate. I'm sure I've had 78 litres on a fill before so you should be getting more. The tank size is actually a huge plus for me as if you're on a long trip it's easy to get 400+ miles range.
Stupid question but I assume that your gauge needle at full is fully round at the top? I find some fuels are frothier and cause the pump cut out to kick in prematurely, sometimes it can be the angle of dangle of the pump into the filler neck that exacerbates it. This happened recently to me in France, thought it was full but when I got in the car it was 5-10 litres short of full.
That's my point - only two of my 60+ tanks have seen me do more than 300 miles (best is 324 miles at 26mpg). On that occasion, the fuel light would have been on for a few miles, but when I came to fill up, it only took 57 litres. Basically, the gauge is under-reading and the low fuel light is coming on way too early. That said, its better this way than the other...Stupid question but I assume that your gauge needle at full is fully round at the top? I find some fuels are frothier and cause the pump cut out to kick in prematurely, sometimes it can be the angle of dangle of the pump into the filler neck that exacerbates it. This happened recently to me in France, thought it was full but when I got in the car it was 5-10 litres short of full.
Yes, the fuel gauge goes all the way to 'full' after a fill-up.
I have a feeling that the car would simply do 50+ miles after the range indicator says zero. Perhaps what I need to do is put a jerry can in the boot and then drive it until it cuts out. However, I was brought up on carburettor cars where this was always a bad idea. I don't suppose injector are any more tolerant than carbs of pulling detritus from the fuel tank, but I suspect the filters are better.
Yeah that definitely doesn't seem right. I wonder if your fuel level sender is just not floating properly and dropping too soon? Whilst not directly about the fuel level sender, I remember there was a Redpants YouTube video where he uses the access panel on the fuel tank https://youtu.be/8jiTRZkI63I?t=495 Once you've tried to run out of fuel might be a good chance to look inside 
I only have DB9 experience wrt the fuel tank, but the float in the DB9 is in the center of the tank, while the low pressure / suction pumps are in the aft corners which are a good 2.54cm lower (roughly). I have been in my tank a number of times this spring/early summer and even after syphoning out all the fuel I could get to with the float laying on the bottom of the tank, there's still fuel in the back.
The pumps are fed by the syphon pumps and have a well around the pump to try and keep them well cooled and with a constant source of gas to pull from.
As noted, pumps like to be cool and fuel is what cools them. When they get hot they fail faster. For the DB9 the dealer wants $1600 US and your old pump ($1400 core charge). I'm guessing VDO doesn't make the pump basket anymore so they just rebuild your old pump and send it back. The alternative is a $100.00 Walbro or the pump/top of the basket from a Jag XK8 (which is what I'm running).
The pumps are fed by the syphon pumps and have a well around the pump to try and keep them well cooled and with a constant source of gas to pull from.
As noted, pumps like to be cool and fuel is what cools them. When they get hot they fail faster. For the DB9 the dealer wants $1600 US and your old pump ($1400 core charge). I'm guessing VDO doesn't make the pump basket anymore so they just rebuild your old pump and send it back. The alternative is a $100.00 Walbro or the pump/top of the basket from a Jag XK8 (which is what I'm running).
Minglar said:
I really don’t understand why anyone would intentionally wait until the low fuel light illuminates before they decide to refuel, especially when you say you hate the anxiety of running low. That makes absolutely no sense at all. I hope you’re not a pilot too! I am firmly aligned with LTP on this issue. BRM.
+1.My wife gets "anxious" if her RS4 tells her less than 120 miles range and fills up at the next garage she sees
Nigel_O said:
olv said:
2007 4.3 here, I do find the gauge pretty accurate (actually both in this car and the 2008 I had previously) and I tend not to fill up before I need to, as the gauge has been accurate. I'm sure I've had 78 litres on a fill before so you should be getting more. The tank size is actually a huge plus for me as if you're on a long trip it's easy to get 400+ miles range.
Stupid question but I assume that your gauge needle at full is fully round at the top? I find some fuels are frothier and cause the pump cut out to kick in prematurely, sometimes it can be the angle of dangle of the pump into the filler neck that exacerbates it. This happened recently to me in France, thought it was full but when I got in the car it was 5-10 litres short of full.
That's my point - only two of my 60+ tanks have seen me do more than 300 miles (best is 324 miles at 26mpg). On that occasion, the fuel light would have been on for a few miles, but when I came to fill up, it only took 57 litres. Basically, the gauge is under-reading and the low fuel light is coming on way too early. That said, its better this way than the other...Stupid question but I assume that your gauge needle at full is fully round at the top? I find some fuels are frothier and cause the pump cut out to kick in prematurely, sometimes it can be the angle of dangle of the pump into the filler neck that exacerbates it. This happened recently to me in France, thought it was full but when I got in the car it was 5-10 litres short of full.
Yes, the fuel gauge goes all the way to 'full' after a fill-up.
Does over 300 miles easily to Le Mans regularly with spirited driving so does sound like a gage problem for you
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