Power loss

[MiniPetrolHead]

Hi there everyone,

Is it true that when you are low on fuel and the red light has been on for a while (the computer says i can do 17 miles left on the tank) does the ecu restrict the power at all, as i have noticed that when im low on fuel it doesnt feel quite as fast as when its got say half a tank in?

Any ideas would be great!

Alex

[Richard Crofts]

Nah wouldn't think so. The MINI ECU is not a very clever bit of kit and I can't see BMW bothering to add something like that to the computer processes.

[Lucky Dave]

It may be because you are running out of fuel!! and drawing air/dirt from the bottom of the tank?

I dont think the ECU does any restriction due to low fuel, I have driven a car without the fuel gauge working at all and its power was fine.

[MINI-Morgan]

Maybe a drop in fuel pressure with it splashing around in the tank and sucking air instead of fuel. I'd be amazed if its the ECU..... but then it will probably retard the ignition too if its not getting quite enough fuel.

[PmP]

I get the same feeling when my S is below 1/8 full, the performance is less than if ive just filled up, has always seemed this way. Guess it would make sense to put in some sort of system like this.

That said could be down to the injection of fresh fuel into the tank, or the increased pressure of extra fuel in tank.

Maybe it just me.
Have another theory of my own, that when you fill up and open the pump up full as most people do, you could be getting dirt/oil out of the pump and possibly air. I always open it halfway without thinking about it now. Maybe I've just got OCD about my car...

Might be interesting to get a car on a dyno with needle in the red and then 3/4 full.

[Paul@1320]

Mmmm thats intresting maybe thats why our dyno numbers are so low compared to others because its in the red on the dyno but our car is always faster.

[Fevs]

Quote: Originally Posted by PmP (original)

I get the same feeling when my S is below 1/8 full, the performance is less than if ive just filled up, has always seemed this way. Guess it would make sense to put in some sort of system like this.

That said could be down to the injection of fresh fuel into the tank, or the increased pressure of extra fuel in tank.

Maybe it just me.
Have another theory of my own, that when you fill up and open the pump up full as most people do, you could be getting dirt/oil out of the pump and possibly air. I always open it halfway without thinking about it now. Maybe I've just got OCD about my car...

Might be interesting to get a car on a dyno with needle in the red and then 3/4 full.

you got ocd mate i tell ya fuel from the pump is not filtered till it goes through the filter on ya car

and no matter how fast or slow ya pump it you will get some dirt if its there as for the air from the pump if the pump gets air in its stops working as it requires a proper vacume feed so air stops it end of !!!!

[iain cooper]

Quote: Originally Posted by Lucky Dave (original)

It may be because you are running out of fuel!! and drawing air/dirt from the bottom of the tank?

I dont think the ECU does any restriction due to low fuel, I have driven a car without the fuel gauge working at all and its power was fine.

I would agree with this, you should never on purpose allow your tank to go as low as this.

done on a regular basis, you are asking for problems with your fuel system.

[PmP]

Quote: Originally Posted by iain cooper (original)

I would agree with this, you should never on purpose allow your tank to go as low as this.

done on a regular basis, you are asking for problems with your fuel system.

I experienced this again today, needle was just below the 1/4 full mark, and put £30 of fuel in and on leaving the garage it accelerates better

[MINI-Morgan]

Doesnt make sense to me unless the fuel is going off really quickly?? Maybe the part biofuel mixes are less stable over time? moisture in the fuel? I cant see it being fuel pressure or you're talking lean mixture all the time...

p.s. if anything the difference between empty and 50litre of fuel would be slower with that much extra weight on board.

[MiniPetrolHead]

Its weird that the car feels faster with a healthy level of fuel on board rather than a really low level, my Mini One also used to do it. I only really noticed it when i was coming to the end of a tank of 95 ron fuel (they didnt have 99) now its got 1/4 tank of tesco 99 its a little rocket!

Alex