Pessimistic Fuel Guage??

[mozzzy_2000]

Just a thought; how does one get in more than 45L when its supposed to be a 45L max tank? lol
I've always thought the fuel guage to be rather wacky. Whenever I fill up, it so generaously tells me I have over 500Km to go when in reality I've never got more than 400kms if I am really lucky and on average its less than that. Have you guys also noticed that driving sedately uses up almost the same amount of fuel as when you're driving hard? It makes almost no difference according to my fuel guage. At the end of the tank I have covered virtually the same Kms regardless of distance driven or how lead footed I have been.
And yes I hate it when it tells you you've got 10kms left then all of a sudden you've got none in the blink of an eye and panic sets in.

[VW GTI]

hahahaha... seriously though I find the speedo wildly optimistic compared to several satnavs I've used, it seems to overstate the GPS-measured speed by at least 5km/h

It's out by about 10%, I've had mine checked on the dyno (and my 17s make it a little more accurate).

Just a thought; how does one get in more than 45L when its supposed to be a 45L max tank? lol

They understate it, to fit into the hole they put it in, it may need to be a slightly odd shape so they round to a nice number. I don't think I've heard of a fuel tank that is 46.8L or something. They are always 25, 40, 45, 60 etc.

[Roodosutaa]

Just a thought; how does one get in more than 45L when its supposed to be a 45L max tank? lol

The filler neck's probably got a litre or two in there too plus I'm sure the servo pumps aren't exactly super-accurate, if anything they'll probably make them overstate a bit but hopefully within legal margins

That'd explain why I consistently get 5.6 litres into a 5 litre can at every servo I've used even if you allow for a bit of expansion space in the can.

[Cygnus]

Most ive ever got in is 54.5L

Ive ran the car out of fuel on purpose. I got 120km with it on 0 K's to go. (driving sensibly)

Looks like you got ripped off by the petrol station!

[Chuck]

isn't running it that low not too great for the fuel injection system?

..just something i have heard, not sure if its applicable to our Pogos tho

[Blitzen]

isn't running it that low not too great for the fuel injection system?

..just something i have heard, not sure if its applicable to our Pogos tho

Its definatly not good for fuel pumps. The fuel pump is lubricated by the fuel, so if the tank nearly runs dry, and you do this alot, you can kill your fuel pump. Do a dry bench test of an electric fuel pump, and see what happens.
Also, it has the ability do suck up the unwanted detritis that can exixt in the pick up point in your fuel tank, and then clog your fuel filter. this is alot cheaper to replace than a fuel pump, but an annoyance none the less.

[Kai]

Is that even possible?????

This explains a lot ..... you must have a V8 in there Kai .... only way you can ever beat another V8 .....

So, the secret to refuelling a V8 then .... switch it off when you fill up .... otherwise you'll never get it full ..... it consumes more at idle than what the pump can provide ....

Looks like you got ripped off by the petrol station!

It was bone dry when i filled it up.

There is a little button in the fuel cap. No idea what it is. Everyone says not to press it. It lets some gas out. And then lets you put more fuel in. Someone said its an expansion tank or somthing?? Whatever it is. I press it. And it lets me put another 2L in. Then i press it again and put another 1.9L in then press it again and put another 1.5L in...

so on and so on...

I have the receipt. As i keep them all. So i dont mind going through all 10000000 of them to find it

Oh and in regards to the servo ripping you off thing. Just recently i put 25L into a 20L jerry can. They told me my jerry can holds more then it says. YEAH RIGHT!

[T Go]

It was bone dry when i filled it up.

There is a little button in the fuel cap. No idea what it is. Everyone says not to press it. It lets some gas out. And then lets you put more fuel in. Someone said its an expansion tank or somthing?? Whatever it is. I press it. And it lets me put another 2L in. Then i press it again and put another 1.9L in then press it again and put another 1.5L in...

so on and so on...

Dont press that button 2 many times... could be like the Reebok Pumps... one more press and the shoe explodes!! Messy when its a Polo tho... haha.

[CatonaPC©]

I consistently get 5.6 litres into a 5 litre can at every servo I've used even if you allow for a bit of expansion space in the can.

The can is probably legally allowed to be filled with 5 litres of fuel only. The rest of the space is to allow for expansion.

I have 20 litre jerry can. I always fill it with 20 litres and no more and there's at least 3 inches of space above the fuel.

[mozzzy_2000]

isn't running it that low not too great for the fuel injection system?

..just something i have heard, not sure if its applicable to our Pogos tho

Yeah I was gonna ask that too. I did that a couple of times in my previous car, a subi, and my mechanic reckond you can do all sorts of damage. The fuel pump doesn't like it and he said something about damaging the catalytic converteras well. Beats the hell out of me how it can damage it though. I only ever did it twice and the car was still going strong after 17 years of pretty rough abuse.

[Blitzen]

Yeah I was gonna ask that too. I did that a couple of times in my previous car, a subi, and my mechanic reckond you can do all sorts of damage. The fuel pump doesn't like it and he said something about damaging the catalytic converteras well. Beats the hell out of me how it can damage it though. I only ever did it twice and the car was still going strong after 17 years of pretty rough abuse.

Its definatly not good for fuel pumps. The fuel pump is lubricated by the fuel, so if the tank nearly runs dry, and you do this alot, you can kill your fuel pump. Do a dry bench test of an electric fuel pump, and see what happens.
Also, it has the ability do suck up the unwanted detritis that can exixt in the pick up point in your fuel tank, and then clog your fuel filter. this is alot cheaper to replace than a fuel pump, but an annoyance none the less.

I have no idea how it could damage a Cat Converter, but I have destroyed a fuel pump doing a dry bench test just to see what running a fuel tank dry can do.

[mozzzy_2000]

I have no idea how it could damage a Cat Converter, but I have destroyed a fuel pump doing a dry bench test just to see what running a fuel tank dry can do.

I think, as it was mentioned, debri can perhaps get through the exhaust and clog up the catylst perhaps? I think thats what my mechanic told me.
But yeah running out of fuel serves too purposes; You'll never do it twice and you'll find out the maximum capacity of your tank! No more guessing next time.

[Bubu]

Lets get one thing clear people!

Running low on fuel does not mean your fuel pump sucks dirt from the bottom of the tank. I dont know if any of you have ever pulled out an in-tank fuel pump out, I have, if you have a look at it, the pump always draws fuel from the bottom of the tank. Its the only way your car can use that very last liter of fuel before the engine stops.

The fuel that goes in your car is generally quite clean and any dirt that may get in the fuel tank will be trapped in the fuel filter. The only dirt that may get to the combustion chamber would be microscopic. And once the spark fires it would be disintegrated due to the high temperature.

[FL00DY]

My light doesn't come on till 30-40km. Closest I've filled to 45L is 42 and I had been cruising on 0km for some time. I almost always fill mine at 10km to empty.

Is it perhaps something about chipped cars that there light comes on earlier? I haven't read the full thread.

[Blitzen]

Lets get one thing clear people!

Running low on fuel does not mean your fuel pump sucks dirt from the bottom of the tank. I dont know if any of you have ever pulled out an in-tank fuel pump out, I have, if you have a look at it, the pump always draws fuel from the bottom of the tank. Its the only way your car can use that very last liter of fuel before the engine stops.

The fuel that goes in your car is generally quite clean and any dirt that may get in the fuel tank will be trapped in the fuel filter. The only dirt that may get to the combustion chamber would be microscopic. And once the spark fires it would be disintegrated due to the high temperature.

Thats generally true, however I have removed an in tank pump from a car with a plastic tank(an EL Falcon) to find ou why the pump had failed, and found a piece of rusty metal about 1.5mm accross that has lodged in the pump.
A cool little experiment to do on a fuel filter(and just about any filter) is to cut or pull out the casing, and then cut out a section of the filter element. You then squeeze this element in a vice to get all of the fluid out, then remove it and open like an accordion. In doing this you can see what you filter has been catching, and it is also good for fault finding and componant failure analysis.