Fuel/Distance Remaining, how low can it go?

[Ryy]

I've got it to 5 miles remaining, but fact is each time I get it there (and the same with everyone else I take it), you'll change your driving style. Your miles to empty will work on how you have been driving, so if (like me) you drive a lot more conservatively trying to get it to the preferred cheaper station, then the car will stay on 5 miles to empty for ages, so it's so accurate as people are saying. I dunno how bout the litres, but "how low can it go", depends on how YOU are driving at the time and for the last whatever it is the car references from.

[maisbitt]

Yep: 24 miles past zero whilst averaging 52mpg for the journey it stopped 1/4 of a mile from home after I couldn't find a local garage serving fuel at 7:10am on a Sunday - by my reckoning I would say my reserve was about 2 litres!

It started up again without a hitch once I got 5 litres in from a jerry can that my mate always keeps in his boot

The "0 miles" does cut in a lot sooner on my new Roc - don't know whether that's a feature of the newer cars or difference between 170 and 140 TDIs. It took 55.3 litres to fill (including replacing the contents of the jerry can), my old one once took 57 litres without dying on me. It definitely seems like my 11 plate 170TDI has a smaller tank than my 09 140TDI.

[RW1]

Lets not play the game of lowest..... There are implications for running a modern fuel system "dry" with it being very high air and fuel pressures involved in the system, particularly direct cylinder injection.

Emergencies understood but it is fool hardy to not fill up by the time the red warning area is reached and warning lamp comes on.

C.

[maisbitt]

On past experience with the last Roc and previous Golfs I thought I had enough to get me 24 miles on the reserve at 52mpg, I was always going to fill up for a complete tank on the return from dropping wor lass off at work.

I couldn't believe there were people serving in the Shell garage at 7:10am if you wanted a sunday paper, but won't turn the fuel pumps on until 8am. Luckily enough I was doing all of about 15mph on a flat piece of road when it ran out of fuel or shut itself down before it was starved of fuel (more likely I think) as a safeguard.

Just goes to show that the "reserve" tank is not something you can count on - by my experience mine is considerably less than the published 7L, more like a smidge over 2L (24/52=0.46 Gallons = 2.09L).

[Trickytree]

I've had 40+ miles from a zero reading on my TDI and filled it up to just over 56L.

[goatboy]

surely when it says it has 7 litres reserve, the reserve is from when you get into the red, not 7 litres left from when it says you have no miles left.
Certainly seems about the right kind of distance left for 7 litres when the warning flashes up.

I've got mine down to about 30 miles to go and have not had to fill more than 51 litres...

[maisbitt]

I had a 57L fill once on my previous Roc (140TDI).

I have always taken it to mean that the reserve is from "0 miles", otherwise it's not really right to call it a reserve.

If the Roc tank is 55L, I would therefore expect the car to say "0 miles" when there were 7L left in it/48L used from a complete fill.

I think that the only thing you can be sure of is you can't rely on the "reserve" to get you beyond "0 miles left", it could give up at any time.

Still not sure why my newer Roc gives you less notice (40 miles range left) than my older Roc (90 miles) that your fuel is low, although you can't use that as an excuse to ignore the needle on the fuel gauge.

[Richard A]

Lots of interesting real world experience above, thanks.

I do have one question. My Scirocco manual (English, print status on back cover 24.08.2009) says in a table at the bottom of page 180 that the fuel tank capacity is "approx 55l, plus approx. 17l reserve".

Is this a misprint? To be honest 7l, as quoted in numerous posts above, sounds a lot more realistic. 17l sounds too much, but I'm wondering where folk are getting 7l from.

I checked it out after getting caught short in the Thuringian mountains last year - that 'miles to go' indicator drops very quickly when you are driving up steep, twisty hill roads!

[maisbitt]

Richard A:

55L + 7L reserve seems way off the mark for my experience (+17L even more so). When I ran out it was only a 56L fill (and i'm taking the volume from the jerry can into account there). My "miles left" counter tells me to fill up at 40/45miles left and despite driving economically (averaging at least 50mpg) those miles fall off very quickly - i'm lucky if I drive 25 miles before "45 miles left" becomes "0 miles left".

My new Roc definitely has a smaller tank than my old Roc (or my high level computer's economy calculations are way off), but it appears that the users manual doesn't reflect this.

Assuming "reserve" is from when the car reaches zero - I had about 2L left, judging from when I ran out.
Assuming "reserve" is from when the computer tells you to fill up (at about 40/45miles left for my TDI), I had about 6L left to when I ran out, assuming I travelled 40 miles from "40 miles left" to "Zero miles left", which was more like 30 miles + 24 miles taken beyond zero, all at an indicated 50-52mpg - so about 5L in reality.

Don't trust it beyond "0 miles" is the key message.

Just waiting for the robbing b'stards to lower their prices since crude oil prices dipped 12% over the last 6 weeks and Diesel is still 135.9p/L at the cheapest place locally - it should be about 125p/L.

[RW1]

In Booklet 3.1 it states.....

The fuel tank holds about 55 litres.

When the needle reaches the reserve zone (MFD message, lamp and acoustic warning) ......as reminder to fill up.
At this point there are still about 7 litres of fuel in the tank

Says the same in the 3.2 booklet

Booklet 3.3

Fuel Tank Capacity approx 55 litres of which reserve is approx. 7 litres

(All dated 03.2009)

The "miles to go /km to go" is dynamic on the state the ECU is fuelling the engine/tank contents. So it does vary and very dramitically if the engine gets some welly. Or engine is cold started obviously.

You forgot the £/$ rate change, need to put that in the abacus.

C.

[Richard A]

Richard A:

55L + 7L reserve seems way off the mark for my experience (+17L even more so). When I ran out it was only a 56L fill (and i'm taking the volume from the jerry can into account there). My "miles left" counter tells me to fill up at 40/45miles left and despite driving economically (averaging at least 50mpg) those miles fall off very quickly - i'm lucky if I drive 25 miles before "45 miles left" becomes "0 miles left".

Thanks, maisbitt, that pretty much confirms my thinking and that there is a misprint in the manual (i.e. seems like it should be "55L, of which 7L is reserve", rather than "approx 55l, plus approx. 17l reserve").

Now I think about it, I got about 53.5L in after the Thuringia experience (I managed to get to the hotel, but the next morning I walked to the fuel station after asking directions, to check exactly where it was, so I didn't make any unnecessary and tank emptying detours en route), sounds like I was pretty close!

PS, some above are counselling a tow to the local dealer before refilling after a dryout, but there's no warning in the manual to that effect (although it does warn about possible DPF damage during the 'running out' phase) and it sounds like you did a jerry can refill and restart with no problems.

[RW1]

PS, some above are counselling a tow to the local dealer before refilling after a dryout, but there's no warning in the manual to that effect (although it does warn about possible DPF damage during the 'running out' phase) and it sounds like you did a jerry can refill and restart with no problems.

The references weren't to absolute dry hence the use of quotes......

1) Allowing your fuel tank to run low can cause sediment in the bottom of the tank to clog the fuel filter.

2) Running on empty can also cause the fuel pump to become exposed and overheat, as it is designed to sit submerged in the fuel.

3) Very high pressure valves exist and air gulped up by the fuel pump in a turning maneouvre which forces the tank fuel away from the fuel pump intake. This will push air pockets through the system causing surges on the pump and valves in the fuel system resulting in possible damage. The max. fuel pressure in the high pressure part of a TSI fuel system for instance has a pressure range upto 120bar/1,800lb per square inch.

----

4) And on absolute dry, you could lose control of your car if the tank runs completely dry and the brakes and power steering stop functioning due to the loss of an operating engine and alternator. Not something to be caught with at 70mph on a fast road or going down a hill incline.

C.

[maisbitt]

Something I forgot to add. My car kept power steering and brake servo assistance as I coasted to a stop, and I rolled it into a parking bay. My car didn't splutter at all before the engine stopped - it was as though the Roc decided to cut power/fuel before it was at risk of pulling air through the injection system instead of fuel.

[maisbitt]

You forgot the £/$ rate change, need to put that in the abacus.

C.

I thought that a dollar on crude exchanged to a penny at the pumps on a litre. Abacus or not - a 12% drop in the price of crude in the last 3 weeks and no reduction at the pumps is plain wrong. Now that the fuel companies have had huge profits from recent surges, they're under pressure to keep making the kind of profits that should've been considered a one-off a few years ago when the crude price spiked at about $140 a barrel. It's now at less than $90 a barrel for WTI from around $115 in May, and we saved about 3p a litre on the initial drop from $115 to $110 and no more since. Robbers.

[mortc002]

with a diesel 170 I was on 0 for about 7 miles, arse was clapping the whole way!

[goatboy]

I was down to 15 miles to go the other day (by accident and I drove very carefully averaging 56mpg by the time I got to the pumps) and still only managed to get 52litres in the tank.

[RW1]

no more since.

Cos since from that time the £ / $ rate has changed 3.6%..... in the wrong direction! Cancelling out any further drop and the exchange rate is going worse in trend so it will raise pump prices again soon unless there is a significant drop in crude price due to such supplies as Libya's oil production coming back on stream. Heaven forbid if the Chinese economy wakes up after languishing around for the last 12 months. Then you'll see £2/ltr at the pumps.

C.

[maisbitt]

RW1: I still think that a 12% drop in the price of crude (in dollars) vs a 3.6% drop in the value of the pound to the dollar should still mean a noticeable reduction at the pumps.

Something that costs 12% less in dollars and then factoring 3.6% more because the pound has weakened surely means that crude is still almost 9% cheaper in pounds than it previously was (in pounds). This is just blatant profiteering and the government don't care as they get extra VAT revenues when the price goes up due to external forces and not as a result of a duty increase. If they applied a single level of tax that didn't change then they might have more motive to ask why the petrol companies aren't passing on reductions in the raw material cost.

BP, Shell and the rest got a 50% profits boost a few years ago when the price of crude spiked at its highest ever level and are reluctant to see it as a windfall - they expect those profits every year now no matter what the price of crude is.

No wonder there are 2 unsold R's in my local dealership right now (saw them while getting a warranty fix on Tues and this morning).

[IROC-CH]

Morning all

I have just been reading this thread and thought I would put my two cents in. Normally I hate going to the petrol station so i fill up right to the top and run it low. That and have competitions with my friends to see how much we can squeeze out of one tank. So normally I am 63 liters to fill up. One time i was trying to beat my mates 850km from one tank he has a mini cooper s.

Anyway you can see from the pic I managed 831km from 63.4 liters. Then i lost my nerve and filled him up.

[maisbitt]

IROC-CH: How did you manage to get 63 litres into a 55 litre Roc tank? Do different markets have different sized tanks?