Frantic Fuel Gauge

4.2 V8 40v biturbo - 450 bhp
4.2 V8 40v biturbo - 480 bhp (plus)
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chriswebb9
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Frantic Fuel Gauge

Post by chriswebb9 » Wed Jan 28, 2009 11:30 pm

Hello fellow forummers!!

Here's a new one for you - Do you have a fuel gauge that enjoys going to the left overnight?

What the pheck am I on about you ask? Well obviously these cars are keen drinkers, in fact I ought to call mine Oliver, as it's got a thirst just like Mr. Reed had.

But seriously, From having vapour in the tank, if I put 40 litres in, which should be half a tanks worth (as 80litres really is as much as I can get in), the fuel needle jumps somewhere up around the area between half way and 3/4 mark. That's the 1st sign of the inaccuracy.

Secondly, once the needle goes just below the 1/4 tank mark and shows around say 40 miles range, if I park the car overnight on the drive, the following morning when I jump in and switch on, the orange warning lamp and beeper come on. The range then shows something like 25 miles or so.

I used to think that the fuel was leaking or evaporating away, but monitoring the gauge and fuel computer, there's no way that my Gauge is displaying the German accuracy that one would expect with a gauge.

My question to the panel is - Have you noticed the same characteristics on your car/s? If so, was there a fix, or this a trademark on these cars and a cunning way of making sure you always visit the pumps before the GO-GO juice runs out?


As always, I'd love to hear your findings and any keen fan will be keen to read your views too.


Kindest Regards,
Chris Webb :wink:

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RE: Frantic Fuel Gauge

Post by HYFR » Wed Jan 28, 2009 11:43 pm

isnt it because fuel consumption is dramtically reduced when the engine is cold and so when you start your engine the next morning (engine cold), its using a much lower MPG figure to calculate range based on whats left in the tank ? ? ?

turbonutter68
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Post by turbonutter68 » Wed Jan 28, 2009 11:57 pm

I've had a couple of A8's and both did the same but much worse.Range could be 60-70 miles when I parked up and only 20 or less the next morning! Annoying but I just learnt to live with it.A cold engine probably had a lot to do with it.

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Rupert
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Post by Rupert » Thu Jan 29, 2009 12:06 am

Switch the DIS to show current MPG, you might get a shock tomorrow morning when you drive to work! :D
It dumps fuel in like it's going out of fashion.

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chriswebb9
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Fuelling the debate

Post by chriswebb9 » Thu Jan 29, 2009 12:13 am

Dear David & Turbonutter,

Thanks for your comments and I agree that the computer side of the display along with cold starting will indeed produce lower ranges - it does this to me every morning and then rises as I gently drive along to warm the car up.

I'm not bothered by this and like you have learned to live with it. Upon thinking about it, my main query with the gauge is actually the needle itself.

The best example I can think of right now, is that if I park up with the tip of the fuel needle just touching the red zone, by the morning, it won't even rise up off the far left hand datum point, suggesting that I have no fuel left.

I appreciate the computer's trying to work out the range based on circumstances, but I assumed that the needle still works off a sender in the tank via a float mechanism. If it does, then I'd have expected it to be in the same place by the morning.

I'm off to my dealer soon anyway, so I'll ask out of curiosity, but base :wink: d on your comments, I won't be making a big deal of it - I just wanted to settle my mind on why it does it.


Regards,
Chris

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RE: Fuelling the debate

Post by johnny11 » Thu Jan 29, 2009 9:40 am

after owning mine now for over 2 years i`ve come to the conclusion that the gauge goes quicker to the left from half a tank onwards, from full to half i seem to get more than from half onwards, and this is on long journeys of 500miles

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Daveperc
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RE: Fuelling the debate

Post by Daveperc » Thu Jan 29, 2009 10:02 am

Got exactly the same symptoms/issues with mine. I've come to the conclusion that it's a "feature" of the car :?

Also noted that when I start in the morning, the range shown is a lot less than reality. Drove 25 miles to nearest filling station from cold with range saying "Zero" the whole way :shock: Was a tad nervous over the last few miles, and didn't floor it the whole way!

I simply try and keep mine topped up, even on longer runs, rather than take the risk. After all, I didn't buy it for fuel efficiency! :roll:

Dave

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RE: Fuelling the debate

Post by andyt » Thu Jan 29, 2009 10:34 am

Yeah, I've noticed this too. I get up in the morning believing I've got enough fuel to get to work easily because it was showing quarter full when I er put it to bed. Then when I start the car, the needle barely moves and I'm straight to the petrol station.

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SteveCuz
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RE: Fuelling the debate

Post by SteveCuz » Thu Jan 29, 2009 11:25 am

I think this is common to us all. Just a warning though for something that happened to me bout 6 months ago. I was doing some very long journeys and was playing games like trying to drive as economically as possible. Mostly on country roads etc so wasn't going to smash any records that I have seen claimed here but I got 26 mpg. Anyway I was going for the challenge of how many miles I could get out of a tank. I normally try to get 300 and unless I have too many fast runs I normally get around this. Anyway I was crusing home on a dual carriageway and had done 340 and computer said 40 more miles. I had 20 more miles to get home and decided to go to my local petrol station. Anyway about 30 seconds later the fuel light came on and 2 minutes later I was chugging along.

It seems that if you drive it very economically you fool the computer even more.

Steve
2011 Audi RS3 Daytona Grey | 2003 Audi RS6 Avant Ebony Black

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Re: RE: Fuelling the debate

Post by HYFR » Thu Jan 29, 2009 11:34 am

SteveCuz wrote:I think this is common to us all. Just a warning though for something that happened to me bout 6 months ago. I was doing some very long journeys and was playing games like trying to drive as economically as possible. Mostly on country roads etc so wasn't going to smash any records that I have seen claimed here but I got 26 mpg. Anyway I was going for the challenge of how many miles I could get out of a tank. I normally try to get 300 and unless I have too many fast runs I normally get around this. Anyway I was crusing home on a dual carriageway and had done 340 and computer said 40 more miles. I had 20 more miles to get home and decided to go to my local petrol station. Anyway about 30 seconds later the fuel light came on and 2 minutes later I was chugging along.

It seems that if you drive it very economically you fool the computer even more.

Steve
I agree the computer is easily fooled.
On one occasion, having filled to the brim, I drove from Birmingham to London, this was on pure motorway and it was fairly busy therefore had cruise control on 65mph most of the way, having done 70miles from full, my DIS was showing a range of 460 !!!! I've even got a photo of it on my phone [will try to post]
Therefore a theoretical range of 550 miles !
This i doubt is possible unless driven at 56mph cruise control on a level road
I can get indicated 28-29 mpg on cruise control on a motorway doing indicated 70mph.
Where it falls down is the MPG on DIS is inaccurate, so where it says 28-29mpg, it really might be 26mpg and so on
So to trust the DIS is at your own peril !

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Rupert
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Re: RE: Fuelling the debate

Post by Rupert » Thu Jan 29, 2009 11:36 am

SteveCuz wrote:.... Anyway I was crusing home on a dual carriageway and had done 340 and computer said 40 more miles. I had 20 more miles to get home and decided to go to my local petrol station. Anyway about 30 seconds later the fuel light came on and 2 minutes later I was chugging along.
LOL, Amateur! ;)

http://rs246.com/index.php?name=PNphpBB ... highlight=

Driving like that is no fun though!

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chriswebb9
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Post by chriswebb9 » Fri Jan 30, 2009 1:41 am

Hello chaps! A big thanks to you all for your comments, I'm relieved to hear you have all made similar observations towards needle behaviour, as I no longer feel I need to bother my dealer about it and your comments made both amusing and worthwhile reading.

Here's the Jerry Springer style closing conclusions - We all walked into RS6 ownership with our eyes wide open about economy and this little forum query, certainly wasn't to whinge about average fuel consumption.
I'm sure we all like to play the odd "Let's see if I can get over 26MPG average on a run, or hit 20mpg average on a tank" games, but the reality is, hearing the V8 burble is like having an itch and not scratching it, you simply have to feel the surge every now and then! - For me it's generally every time I get some wannabe trying to tailgate me, which generally flicks the "initiate hyper thrust mode" switch in my brain and then grin at the speck in the rear view mirror. YOU JUST CAN'T HAVE ENOUGH POWER IN MY OPINION and the next investment has to be - get a real good tune-up done by one of the experts out there, ooh and the brakes whilst they're at it.

Looking on the brightside, it's nice to see SuperPlus Unleaded back into the £0.89 per litre bracket (well in South Wales anyway), as it's a way of fooling yourself into thinking that the car has improved economy per mile!!! There you go, you heard it here first, keep your cars and search for the cheaper pumps!!

I'm off now, but I just want to finish off by saying, it's these kind of forums that not only unite us, but make me (and hopefully others) like we're driving something really special and are part of a real club of enthusiasts - it's nice. Keep it going! :D

Regards,
Chris W

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Post by Ramone » Fri Jan 30, 2009 9:51 am

Funnily enough, I was going to post on exactly the same issue today - its a small world - my 6 does exactly the same.
I'm going to check that drive to work MPG out too.....

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GardinerG
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Post by GardinerG » Fri Jan 30, 2009 10:03 am

A courtesy driver dropped my car off with 10 miles left on the gauge just after I had spent £1,500 having bits done. It's not like I wouldn't have paid them for the fuel, lol. Needless to say I had to drive a couple of miles to the garage on a cold morning with 0 miles left.... grrrr.

It seems to be a feature of the A6 in my experience.

I've never got more than 280 miles on a tank - am I doing something wrong? :D

(no motorway driving, before you ask!)

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Post by MoRS6+ » Fri Jan 30, 2009 2:13 pm

Mine seems to get slightly weird when near empty also. Not only that, but mine makes a weird sucking noise when my fuel is low, but only from cold and only for the split second I turn the key to the first position before I start the engine. It wont do it after that.

I just keep the fuel to a healthy level at all times now to avoid both the issue you've raised and my weird noise issue.

I also find that the car is most definitely quicker and smoother when there is a healthy amount of fuel in the tank.

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