When To Re-fill Fuel Tank

[Phatboy]

Hey guys, searched for this but no cigar

I always thought that it doesn't make a difference, but I heard some people say that you're meant to refill before the needle goes down to the last 1/3 or 1/4 or so (something to do with direct fuel injection/clogging up your fuel filter???). I tend to refill when the light goes on. The fuel gets sucked from the bottom of the tank anyway, doesn't it?

If you refill at 1/3 full every time, won't that mean you will just have more and more % stale petrol in your tank for longer?

eg.

1st tank: 1/3 batch A, 2/3 batch B

2nd tank: 1/9 batch A, 2/9 batch B, 6/9 batch C

3rd tank: 1/27 batch A, 2/27 batch B, 6/27 batch C, 18/27 batch D

etc, etc you get the idea

Granted stale petrol will never reach more than 1/3 of the tank, but with each filling, a smaller fraction of that petrol you put in last year still remains...

[JMW]

Well you pretty much answered your own question in parts, as in "stale fuel at the bottom of the tank" and "the fuel get sucked from the bottom of the tank" !

Main reason to refill before a 1/4 or lower is stop the pump picking up so much crap from the bottom of the tank, ie - more fuel=less condensing of contaminents, also helps prevent surging on acceleration and cornering.

Takes a fair while for fuel to go off or stale, unless its race fuel which has a shorter shelf life.

[krzysiu]

If your running a standard fuel pump you will be fine to run it pretty low. Some aftermarket pumps dont like it when the tank drops below a certain point. Will let someone with a bit more knowledge about fuel pumps explain this.

[Phatboy]

Oh ok, I see. I guess some aftermarket fuel pumps work a bit differently to the stock ones.

If your running a standard fuel pump you will be fine to run it pretty low. Some aftermarket pumps dont like it when the tank drops below a certain point. Will let someone with a bit more knowledge about fuel pumps explain this.

[(OO)SKYLINE(OO)]

I just fill it when it gets to about half tank...

But nothing below a 1/4 tank just for safety.

[Impact]

lol i run mine to near bone dry as im a cheap bastard and cant always afford to fill up

[frozenwaffles]

why does it matter if you run till low 'as you'll pick up shit'?!?!?

isnt that whats the fuel filter sock is for and then the fuel filter???

[br3ndan]

i like to fill mine up around half tank.

Reason for this? I like to be prepared. I hate it when i go out and i see my tank is nearly empty and i have to go out of my way to fill it up. If i fill up around half tank it means i can wait until i pass by a BP and fill her up when its convenient to me. If however its at 1/4 tank left i have to go out of my way to fill it up.

From my experience its never good to run a car on less then a 1/4 tank. As hard cornering and launching or even braking the petrol can run away form the pick up point.

Stop being stingy people and just fill her up.

[GUN_METAL_GTR32]

lol i run mine to near bone dry as im a cheap bastard and cant always afford to fill up

lol

as do i, but if i run it really dry my engine light comes on and stays on till about 15 minutes after i have filled up lol.

[ali-turko]

alot of ppl saying that you'll pick up shit from the bottom of your tank is bullshit in most cases, i cant member where i saw it but a dude took his fuel tank off his r32 gtr and the bootom of the tank had no crap whats so ever,

remember there is a sock on the end of the fuel pump and a filter in engine bay

[Basti]

lol i run mine to near bone dry as im a cheap bastard and cant always afford to fill up

i have gotten up to 20km out of the tank, AFTER the fuel light was STEADY on. not just on with braking. im such a cheap karnt

[pipster11]

i was testing how out my fuel guage is

the light hasn't come on yet but i'm well and truly out of fuel

was strange tho cos i drove it the day b4 it ran out and no signs of it getting low (no fuel light but low guage)

went to start it the next morning and it barely ran

jarry can run for me now

least i know where the limit is now - i hate being poor

[Phatboy]

Lol... ok. Guess opinion is still divided. Guess I will stick to fill up at 1/4 if it's cheap - otherwise just do it when the light comes on. Filling up at 1/4 means 25% more petrol stops. Can't really be bothered.

[omega36]

The last time I tested my fuel level light I ran out of fuel :|

[battery]

i fill up when it gets to 1/4 not because im worried about picking up shit but i just get paranoid about running out of fuel lol

[Smity42]

I tend to fill up when the light comes on. Not because I'm cheap (beleive it or not people, you're still buying the same amount of fuel in total regardless of if you fill up twice with half a tank or once with a whole tank), but more because I'm lazy so don't stop for fuel unless i'm forced to

[pipster11]

well took the fuel pump out after having run it pretty much dry and was quite suprised what i found

it was spotless and there was cool baffles everywhere

so there was not much crap on the pump either, put some fuel in it and took it to the servo

runs well and not a problem

moral of the story, maybe there isn't as much crap in there as you think

[SiR_RB]

i have never ever let my fuel go low enough for the light to come on....there realy is no reason as to why u would let ur light come on and continue driving for another 50kms

i always top up when my fuel gets to 1/3

if u continue to let the light come on, ur more likely to suck up rubbish...but thats what the fuel filter is for i guess

[paulr33]

mythbusters ahoy

the pump is ... on the bottom of the tank

so regardless of how much fuel is in the tank

it sucks from the bottom with a sock (filter)

and there is an inline fuel filter before the fuel rail

so running empty, does no harm

[Phatboy]

Thanks Paul, that's what I thought.

Just had my car serviced today and the fuel filter (which I doubt has ever been changed since the car was made 8 years and 55k ago) was pristine, despite only filling up when the light goes on every time. Put my mind to rest.

mythbusters ahoy

the pump is ... on the bottom of the tank

so regardless of how much fuel is in the tank

it sucks from the bottom with a sock (filter)

and there is an inline fuel filter before the fuel rail

so running empty, does no harm