[Shery1997]

I have recently purchased a BMW 320i 2004 Auto and its fuel consumption is 5.5km per litre according to its own computer. This translates to

3.4 miles per litre or 15.3mpg

How are people with 2001 e46's with bigger engines getting more mpg?

I drive sensibly and keep revs before 2000- 2500

Please help as to what could be the cause?

 

[FredoinSF]

Reason is simple, BMW deployed special software to increase fuel consumption for all UK registered cars as a result of Brexit decision. Sorry, couldn't resist...

Seriously now, there are so many factors. Number one is have you reset the computer? Have you compared it to actual consumption over a few fill ups? What kind of driving do you do? The car is 12-13 years old, has it been maintained? What is age of spark plugs / filters / any vacuum leaks??

 

[Shery1997]

Hahahaha! & I will fill up today and do an actual consumption & when I reset the computer through the knob on the speedo it only resets the mileage and not the consumption. I have no maintenance history on the car. So far I have changed the Engine oil (Castrol) Original oil filter and original air filter. There is a "44 solenoid value tank ventilation" which is indicated by the engine light ( Codes read by BMW) so I changed the seal on the fuel cap and I am waiting for the light to go out hopefully.
Also there is a fault in the steering angle sensor.

 

[Shery1997]

Should I get the spark plugs changed?

 

[FredoinSF]

To reset consumption push and hold the button at the end of turn signal stalk you use to cycle through the various measures.
As far as what to do maintenance wise it's dependent on mileage, and what has been done before (assuming you have some history), and how long you want to keep the car and how much you want to invest into it. If you have no records, assuming nothing's been done would likely reflect the sad reality.

Cheers.

 

[Art Teach 325Ci]

Never use the computer. Fill up the tank do your driving then divide your km driven by litre needed to refill that will give you your true consumption.

As with any used car, without a service record or obvious signs something was done assume it wasn't done including filters and fluids. I'd go ahead and change your plugs if for nothing else preventive maintenance. Fuel filter is another cheap fix that has probably never been done. Like FredoinSF mentioned the possibility of a vacuum leak somewhere is possible. Do you have stock wheels and good rubber? Proper air pressure?

Also did you have the car inspected before you bought it? I saw biggest improvements in my car after getting rid of the wide low pros the po had on it.

 

[Shery1997]

Thank you so much FredoinSF I was able to reset the computer.

Yes I will be trying to get hold of spark plugs and fuel filter on Tuesday and see how that goes. How could I check if there is a vacuum leak?

The car does have stock wheels and decent rubber & the air pressure is correct as well.

No the car was not inspected before purchase unfortunately