why am i getting such bad fuel economy?

[adashio]

ok first off, how big are the tanks in the 1995 model 520i's
my display reads 80L but when i fill up i only put in about 60, unless it has an AWEFULLY big reserve.

my fuel consumption is 18L/100 on average which equates to 15miles/gallon

why is my fuel consumption so bad? its worse than the v8's driving round town . any help would be very useful. thanks

oh and i used a fuel additive to clean out the engine but did not help much

i also dont use the cheap fuel. i use middle of the range octane 95 i think it is, as opposed to octane 92

whats the first things i should check/do

[Anton CH.]

Wow 18l/100, thats sounds pretty bad. How's the idle?
First thing that I'd check would be for vacuum leaks.

[Morgenster]

Well something must be wrong cause I get 9,5 l/100km on petrol and I put my foot down pretty hard. Sure there's no slow fuel leaks?

[DaveVoorhis]

Just under the front middle of the plastic engine cover is a fuel return hose that connects to the fuel rail. Make sure it isn't leaking.

[Ross]

A foot in the throttle body?

[Morgenster]

ok first off, how big are the tanks in the 1995 model 520i's
my display reads 80L but when i fill up i only put in about 60, unless it has an AWEFULLY big reserve.

As for the reserve: do you get a warning light? fuel level senders can start going south on our cars at their age. I know mine drops fast from 80 to 40 and then lingers a little longer which I'm told to be normal. Capacity is definitely 80l.

[e34.535i.sport]

Stry enough i was getting better fuel economy BEFORE i fixed a leak through one of the fuel pipes! However, if you take the right hand rear wheel off and then the mud cover thats where my leak was. There's a few important lines there, maybe worth a check. I get at about 18-20mpg round town in my 535 (not the most economic of drivers either to be honest). Hope you get it sorted let us know...

[adashio]

hi, thanks for everyones input
must find time to check these things!

idle is quite good, although it does have that "old man car tick" you know the one? this isnt related, just annoys me, its not a smooth idle, its a tick tick tick tick

i havent gotten any warning lights although havent run the car all the way down into the reserve . if i had to judge i would say i was 10L of hitting empty (past red bar) and thats when i filled up and topped it full at 55L. havent really had the car long enough to fully check and recheck things.

i DID smell fuel inthe car one afternoon,just once though, and hasnt repeated itself and went away after about 15min

oh and no it seems to go down gradually from full to empty...

[NielsGalan]

i havent gotten any warning lights although havent run the car all the way down into the reserve . i...

The "FUEL LOW" light doesn't come on until you go past the red bar. Then the fuel meter can go all the way down along the light. I seldom can fill her up more than 60 liters. Thats because once the fuel light comes on you actually have 16 liters or something in the tank.