[imygaf]

Hi guys

I know there are countless threads on fuel consumption but they all seem to be about diesels. Cant find much on petrol cars.

I have a e92 2.5 325i and am averaging 20.5 if i really try or abput 19.5 if i put my foot down occasionally. The official urban figure is 23.3 and from reading on here most seem to get atleast 25. Admittedly my journeys are not in favour of high mpg, mainly local trips of 5-10 minutes and the odd short motorway run but i was still hoping for a bit more.

So do i just accept it for what it is or could there be something wrong? I have had the car over a year and only once managed to get it over 21. It takes atleast 10 minutes of driving before the oil temp begins to even move from the 70 mark. This is longer than evey other car i have driven but seems to be common with these cars.

[MrBen]

That does sound a bit on the low side, I have a 325i, although the later 3.0 engine, and the worst tank I've ever done averaged at 21.9 MPG, but overall over 24,000 miles so far, I've averaged 26.6 with some motorway driving but most of my time spent in town. On a gentle motorway run it will do mid 30's.

Are you taking the reading from the dash, or actually working out MPG? I use Fuelly.com, which is far more accurate than the on board computer, as long as you can be bothered to put in the details each time you fill up.

[Jamie_E92]

the earlier N52 isn't as efficient thus with the type of driving your doing low 20's isn't really far off the mark, the only real sensors which can affect consumption are lambda (o2) sensors & the crank/camshaft sensors. Could be the thermostat but if your not letting it get up to temp then that wouldn't really be an issue.

[imygaf]

I did have an error code a while ago, sure it was something to do with the camshaft sensors. Cant remember the code but will have a look for it. Was recommended to clean or replace vanos solenoid but not had a chance yet.

Im going by the reading on the dash

[MrBen]

Originally Posted by imygaf

Im going by the reading on the dash

I don't find that very accurate, and rely on actual calculations.

[Jamie_E92]

Originally Posted by imygaf

I did have an error code a while ago, sure it was something to do with the camshaft sensors. Cant remember the code but will have a look for it. Was recommended to clean or replace vanos solenoid but not had a chance yet.

Im going by the reading on the dash

there's your answer then more than likley, when my camshaft sensor was down on my old 330ci i noticed an MPG drop of 5 and lack of performance.

[imygaf]

Thanks for the replies.

The camshaft error was atleast 6 months ago. That was reset and i then had error code 2A87, vanos mechanism. After being reset i have not had any errors for a few months although i still get a slight hesitation/misfire very occasionally.

If the error has not came back would it be clear or could there still be a problem. Any idea on cost of camshaft sensor?

[Jamie_E92]

it'll be the camshaft sensor, theyre notorious for failing & are less than £100 for a siemens part, they are very accessible to with removal of the Vanos solenoid.

[ALF_E90]

Sounds like something could well be wrong, but the trip types make a huge difference.

I mostly use my N53 330i for long trips and mostly at 70 or 75, with a bit of thrashing about in between - since I reset the dash when putting the winter tyres on, it has averaged 36.6. My summer average is usually 33-34. I sell vehicle Telematics systems for a living and have trip averages via an OBD plug-in device showing on my satnav and on our tracking software, this gives me trip MPG's which I have worked out to be very accurate - they can be as high as 42 if really trying but for short urban trips then will be low 20's- as low as 20.

The biggest difference I notice with something like my wife's 1.6 FSi Golf or a loan 116d is that from a cold start the MPG is much better much sooner - I usually have to have been driving for 20+ minutes very steadily to get beyond 30.

[Soul_Glo]

Stick a bottle of techron through it and see how you get on I say.

[Wazza26]

Blimey, that's really low.

I'm averaging 31 MPG - Both town and country road driving.

[oliver51090]

Well my 09 is still getting between 19 amd 23