easiest way to work out mpg

[gazzainayr]

hi folks,im worried my peugeot is using to much fuel..i filled completely up the other day + am wondering what is easiest + accurate way of working out the mpg i am using? i dont want to use the full tank just to get a reading, is there an easier way? thanks in advance

 

[obi_waynne]

The full tank method works well because you know exactly how much fuel you've used. Here's another way but there are issues with it.

Run the car to empty and it stalls. Reset your trip counter and fill up with 15 litres exactly (the more fuel you use the more accurate your reading will be)

Wait until you run out again and you'll know how far you've got on an exact amount of fuel.

Running empty is fraught. Many fuel systems get air locks and you risk puling through all the junk in the bottom of the tank.

The full tank method is much simpler to do and without the risks.

 

[obi_waynne]

Method 2: drive for a good bit, top up the tank again and you'll see how many gallons of fuel you used to cover your measured distance (you did reset your trip counter and note your mileage didn't you?)

http://www.torquecars.com/tools/uk-mpg-calculator.php

 

[old-git]

The full tank method works well because you know exactly how much fuel you've used. Here's another way but there are issues with it.

Run the car to empty and it stalls. Reset your trip counter and fill up with 15 litres exactly (the more fuel you use the more accurate your reading will be)

Wait until you run out again and you'll know how far you've got on an exact amount of fuel.

Running empty is fraught. Many fuel systems get air locks and you risk puling through all the junk in the bottom of the tank.

The full tank method is much simpler to do and without the risks.

l would use this method but fill to the brim drive until nearly empty and fill to the brim again at the same fuel pump and facing the same way. This saves having to carry a can and you are bound to run out at a junction or on a roundabout

With regard to sludge in the tank, what sludge? The fuel is sloshing around so any muck that may be in there is constantly being mixed with the fuel. Also, the fuel is sucked from the bottom regardless of how full the tank is otherwise you wouldn't be able to use it all

 

[obi_waynne]

Another urban myth debunked! I'll have none left at this rate og!

 

[old-git]

That's the problem when you have a pedant on the staff

 

[HDi fun]

There are some dubious merits to not running or leaving a tank nearly empty. In the case of steel tanks corrosion is a potential problem so keeping fuel in there stops the tank walls being in contact with oxygen.

'What gunk' is a good question though? Where does it come from? Apart from the tailpipe and filler neck the fuel system is entirely closed anyway

 

[obi_waynne]

Hmm up for debate and justification of my earlier comment!

Filling up with the wrong fuel where one floats on the top is never a problem until the level drops right down, fuel additives put in the fuel by the user, plastics and rubber from the filler decaying, Dust from the atmosphere (this must add up over the lifetime of a car to at least a milligram! )

Clutching at straws now, never tell me you haven't sneezed whilst filling up your car.

 

[T9 man]

Greetings gazzainayr and a Warm Welcome to our TorqueCars Forum my Friend!

Good to have you along with us

 

[obi_waynne]

I forgot my manners too! Welcome Gazzainayr, nice to have you with us. I hope you enjoy the site and stick around and get to know us a bit better.

 

[old-git]

Hmm up for debate and justification of my earlier comment!

Filling up with the wrong fuel where one floats on the top is never a problem until the level drops right down, fuel additives put in the fuel by the user, plastics and rubber from the filler decaying, Dust from the atmosphere (this must add up over the lifetime of a car to at least a milligram! )

Clutching at straws now, never tell me you haven't sneezed whilst filling up your car.

But you are forgetting one thing. The fuel line is fitted with filters to stop this sort of stuff!

But the fuel is still taken from the bottom of the tank so running the fuel low will have no effect on what the pipe picks up.

PS - Sneezes are fluid so will mix with or be diluted by the fuel and pass through the filters

 

[obi_waynne]

You've thought way too much about this!

 

[old-git]

The myth has been around for a long time despite my best efforts

 

[HDi fun]

Yeah - forgot about the line filters. At sub ten quid (for my car anyway - yep BMW service parts are dead cheap !!!!) it's not worth skipping these at service time. Just get em swapped and done with it.

I DO, however, advocate the use of good quality fuel - leave supermarket stuff alone in general. I have NO concrete evidence to support this recommendation but the circumstantial evidence ie. I've not yet need to replace a fuel injector or any carburettor component, or any other fuel system component in over 750,000 miles of driving and of car ownership.

You'll not damage the engine with dirt if the filter(s) are clogged but should fuel starvation occur you are likely to mess up the emission control system - cats and lambda probes etc.