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Is my fuel gauge broken? / My fuel gauge reads wrong. / How much fuel can I get in my tank?


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#1 Sprocket

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Posted 10 January 2006 - 12:00 AM

Right Definitive results after a 3 1/2 hour drive to run the car almost dry.

Take into consideration that this was tested on a 1275 Single Point Injection car as earlier parts may be slightly different depending on year.

Results

I drove for 1 3/4 hours from when the needle was totaly covering the red before the engine started to complain. The engine idled without problem and when the accellerator was pressed it hesitated severely but did not stall. Being gentle with the accelerator I managed to get to the fuel station without adding the five litres I had in the boot, so there is a quantity of fuel still in the bottom of the tank. I added the five litres from the can and topped it off squeezing in as much as I dare, it started to fill the nossle thingy. It took 26.32 litres.

Conclusions

The total fuel that was added was 31.32 litres

The engine still ran at idle without problem so Guestimate 0.7 littres still in the tank when run near empty, taking fuel capacity to 32 litres.

There is still room at the top of the tank that cannot be accomodated by fuel simply by the design of the filler neck. Guestimate there is room for another 1 to 1 1/2 litres.

Guestimate that the fuel filler neck and sender unit on the fuel injected cars takes up 1/4 litre and the fuel pump another 1/4 litre.

Total would equate to 34 litres tank capacity, which Rover state as correct. However what Rover do not clearly state is that figure is tank capacity or fuel capacity which leads to some confussion. Much like the power figures stated by manufacturers. The figure is correct but only they know why it is correct and no one else can replicate it.

Take it from me that if you drive the car with the needle in the red till the engine stops you will get 32 litres into the tank. Judging when the car is going to run out of fuel is the hard part as different engines have different fuel consumption. Like I said I drove for 1 3/4 hours from when the needle was totaly covering the red and that was lead foot driving on country roads.

The very point of the needle will line up with the bottom of the red and not read any farther. When this happens, it realy is time to fill up.

The fuel 'guage' is an indicator rather than a calibrated guage and only indicates that you should fill up, it is not calibrated in litres or gallons.

Edited by Mini Sprocket, 10 January 2006 - 01:08 AM.


#2 Dan

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Posted 10 January 2006 - 12:33 AM

This is a test the Mini Sprocket ran to see how much fuel you can get into the late saloon tank. That's the wider tank which sticks out quite far into your boot, held in by a one piece strap. It's quoted by Rover as 34 litres, or 7 1/2 gallons.

So your fuel gauge probably isn't broken, Mini fuel gauges are funny things.

#3 Guess-Works.com

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Posted 10 January 2006 - 08:48 AM

All I can say is when the fuel guage says empty, put some in it... There's nothing more embarrising than sitting at the side of the road after running out of fuel..

I'll stop and help someone who's broken down, but someone running out of fuel gains no sympathy from me.. that's just plain lazyness.

#4 Sprocket

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Posted 10 January 2006 - 05:18 PM

All I can say is when the fuel guage says empty, put some in it... There's nothing more embarrising than sitting at the side of the road after running out of fuel..

I'll stop and help someone who's broken down, but someone running out of fuel gains no sympathy from me.. that's just plain lazyness.

Very true. Its even more embarasing when, if like me a company car driver, you dont pay for fuel and you still run out (guess whos done that) :nugget: . The AA or RAC dont like it either.

#5 miniboo

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Posted 10 January 2006 - 06:08 PM

Dunno if this makes a difference as you were lead foot country road driving but.....do you know how many miles you got in that 1 3/4 hours driving in the red?

Or how much you got from the full tank?

cheers

#6 Sprocket

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Posted 10 January 2006 - 06:24 PM

That is the next test in progress. Going on the Wirral to Llandudno run so should cover a considerable milege. It may take some time though.

Wait for the results on that one :cheese:

#7 miniboo

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Posted 10 January 2006 - 09:21 PM

ok cool

#8 eddyg

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Posted 11 January 2006 - 10:11 AM

All I can say is when the fuel guage says empty, put some in it... There's nothing more embarrising than sitting at the side of the road after running out of fuel..

I'll stop and help someone who's broken down, but someone running out of fuel gains no sympathy from me.. that's just plain lazyness.

even for people like me whos fuel guage doesn't even work at moment!! lol
will get a new sender unit soon, just got to save the 50 quid!
i drive with an extra 5 litres just in case!

#9 mambaman

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Posted 14 January 2006 - 01:27 PM

does anyone know if the mini fuel system will self prime from a completely empty/ranout tank if say 5litres was added?

#10 minimole

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Posted 14 January 2006 - 03:18 PM

pretty sure you have to prime it yourself. what i when i had completely emptyed my tank is just turned the engine over for a bit without the plugs in... but i was checking oil pressure etc as i had just swapped the engine and stuff.

#11 Sprocket

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Posted 18 January 2006 - 11:16 PM

Fuel consumption results


Standard 1275 SPi with K&N and straight through single back box.

Ran the car almost dry from full and managed bang on 260 miles on 31 litres of regular unleaded, thats 38mpg and that was without trying. Every type of driving style was driven so is fairly good indication of MPG. Better MPG could be achieveble if you don't have a lead foot like I do and also with a taller Final Drive ratio.

As for how many miles are left in the tank when the needle is in the red, I managed 87miles from where the needle point was level with the top of the red line until the engine started to complain.

If you use this information then I take no responseblity for any consequencies that may or may not arise from its use, this is purely a guide where equipment and fuel consumptions will vary between cars, even in the exact same year and model.

#12 miniman andy

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Posted 17 March 2007 - 12:17 AM

All I can say is when the fuel guage says empty, put some in it... There's nothing more embarrising than sitting at the side of the road after running out of fuel..

I'll stop and help someone who's broken down, but someone running out of fuel gains no sympathy from me.. that's just plain lazyness.


HA! i will stop and help only "classic" mini drivers.. . one daylast week i seen one of them bmw Z4's broken down and just laughed my socks off all the way home! mwahahahaha!

i must admit the new mini is a bit of a pain as i class it as a beamer but after all it is still what they call a "mini" and they have resently started rotting away and parts falling off just like my car. so i say count them in! but just dont let them in at the mini shows! lol :D

#13 Ollie180

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Posted 17 March 2007 - 08:12 AM

ok... this post is over a year old :D :D

#14 Davis

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Posted 12 December 2007 - 05:14 PM

Lol Oldschool

#15 Jammy

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Posted 03 January 2008 - 08:55 AM

Recent post from Dan on the subject:

Oh, I don't recommend doing what I did because the crud in the bottom of your tank can be sucked into your carb


ARRRGGHHH, NO IT CAN NOT. Sorry to shout, that comes up fairly regularly and is a myth. Floating crud can be drawn into the fuel system but sediment can't really, the tank outlet is about an inch and a half off the bottom of the tank and is filtered and there is no reason it should get stirred up down there. If you aren't filling up at supermarkets there won't be much sediment there anyway.

Oh so many issues on this thread. First, DTXDave if you can't fill the tank without vapour pouring into the car there is something wrong, check the tank vent is actually venting under the car not into the boot and make sure the tank isn't leaking at high level as obviously that could be very dangerous. A boot full of vapour and fuel with a nice big heavy duty source of fat sparks nearby is a bad thing. Yours is a 7.5 gallon tank by the way.

Jon618, I don't know of any car ever made that has a fuel gauge that you would consider to be accurate. They are all different and vague and all they ever show is the level not the volume so exactly what it will show depends on whether you are moving or parked on a hill or something. If you are only getting 16 litres in then you are only using half a tank. Just keep driving next time and push it until the needle gets a bit lower on the gauge, then fill up and see how much you get in. Keep going until you can get somewhere around 30 litres in when filling to just below the join between the neck and the body of the tank (you can see where the level is then through the filler, it should never be filled into the neck). The total capacity is around 34 litres so if you are pushing it to having only about 4 left you are still quite safe. Then just note how low it will actually go on the gauge, the red sector is only a warning on any car. Keep a full jerry can with you when you are doing this testing, just in case the gauge is actually broken but it isn't likely.

AFAIK the 7.5 gallon tank became standard accross the saloon range in 1973, before that it was used on the 1275GT and I think the Mk3 Cooper S only. From then on ALL SALOON MINIS had a 7.5 gallon tank. This is not as confusing as this thread would make it seem.






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