Fuel efficiency and Older cars : getting tank to empty before filling or not.

Grey_Critic

droopsnoot said:

HedgehogRulez said:

How can you be certain you’ve hit half way in your tank? 

The OP has said several times that they're working it out based on how much fuel they have to put back in the tank until the filler "clicks", and how many miles they've done in that time. 

Which is not really accurate as some pumps deliver at a faster than others and it clicks off due to the backpressure - There will be some foaming during filling and depending on how much fuel is in the tank when you start that also will have an effect.

paul_c123

Grey_Critic said:

droopsnoot said:

HedgehogRulez said:

How can you be certain you’ve hit half way in your tank? 

The OP has said several times that they're working it out based on how much fuel they have to put back in the tank until the filler "clicks", and how many miles they've done in that time. 

Which is not really accurate as some pumps deliver at a faster than others and it clicks off due to the backpressure - There will be some foaming during filling and depending on how much fuel is in the tank when you start that also will have an effect.

Agree, it can make a massive difference - like 6-10 litres of volume still left. The way to ensure consistency is to manually, and without spilling any, get it to the brim. Easier said than done, takes ages, and not recommended (because it can flood the evap system).

prowla

droopsnoot said:

HedgehogRulez said:

How can you be certain you’ve hit half way in your tank? 

The OP has said several times that they're working it out based on how much fuel they have to put back in the tank until the filler "clicks", and how many miles they've done in that time. 

Their receipt will also say how much fuel they've purchased.

droopsnoot

Grey_Critic said:

droopsnoot said:

HedgehogRulez said:

How can you be certain you’ve hit half way in your tank? 

The OP has said several times that they're working it out based on how much fuel they have to put back in the tank until the filler "clicks", and how many miles they've done in that time. 

Which is not really accurate as some pumps deliver at a faster than others and it clicks off due to the backpressure - There will be some foaming during filling and depending on how much fuel is in the tank when you start that also will have an effect.

Yes, though I think they have said that they allow it to click a few times rather than just stopping at the first click.

The issue here is that the thread has grown so long that new contributors are coming along and repeating suggestions that have already been posted and answered.

Nobbie1967

The OP has clearly with made a mistake in their calculations or not filled up completely before they did the calculations. Hopefully they’ll keep refilling once it reaches 2/3 and realise this as the sudden jump in MPG is not repeated reliably.