rubbish mpg 320i

[pirate952]

right, ive been out in the bm twice since i got it, both times ive put £10 of fuel in @ £1.16 a ;litre, and both times only managed 20-23 miles!
so if im right its about 12mpg.
the fuel guage isnt that great, but is thre anything obvious why i wuold be gettin rubbish mpg?
ive not been thrashing it either, pretty gentle country road driving, no traffis or towns.

[Felix79]

My 320 use to give me rubbish mpg also.

[pirate952]

shouldnt be that bad tho, 25-30 average, upto 35 on a run should be right.
manifold gasket could account for some, think i will have to brim the tank, run it til its empty and see exactly how many miles i get to a tank.

[georob]

Thats well below what it should be, what state are your plugs?

[pirate952]

ive not had a look yet tbh, will rip one out.
another question, if i wnt to swap to a 325 exhuast, will i need to change the manifold too?
just thinking if im goin to do the gasket i might aswell do the lot at the same time.

[georob]

No, afaik it would fit fine

[StuBeeDoo]

shouldnt be that bad tho, 25-30 average

That's the sort of figure you should expect.

upto 35 on a run should be right.

You'll be very lucky to get that. I only managed it once - when I was driving like an 80-year-old with both his parents in the car.

think i will have to brim the tank, run it til its empty and see exactly how many miles i get to a tank.

That's the only way to do it. If it's any less than 22mpg the first thing I would do is replace the blue temp. sensor in the thermostat housing.

[capri_rob]

Thats godawful mpg. Check for a leak in the tank/fuel lines. If you've not been driving it hard contrary to what you may read on here they return reasonable mpg. Once you've confirmed there are no leaks get the thing fully serviced and if still no improvement get a local specialist to give it a once over.

[Bob_S]

thrash it..

[pirate952]

right, update after lots of miles, its not that acurate but i shoved £25 in, done about 50 miles, then had to do a long drive so brimed the tank, its back down to where i put the £25 in. if not theres more not less.
so on £54 of fuel at £1.15 litre, i got 305 miles.
i think its about 30mpg that was mainly motorway, but i was late on the way up so 100mph for a bit, mainly 80-90 cruising. (i have a private road from my house to wales) then 70ish all the way home.
i was told teh manifold had a blow, but after another look what i thought first seems to be right, its the tappets or a noisey one, also a leak on the gasket from what i can tell.
are they adjustible?
not had the plugs out yet, but dont know if its me but around 300rpm it almost holds back slightly which iirc is about where the plugs need to work the hardest.
anyway, if ive got the figures right, its not too bad, im goin to run it right down, then brim it again and see what i get. then, before i refil again i will drop some new plugs in and work out what to do with the noisey tappet.

[pirate952]

ment to say 3000rpm lol

[StonyRay]

air filter, new plugs, fuel filter, and check for leaks in the fuel,exhaust and inake system.

[snoops]

right, ive been out in the bm twice since i got it, both times ive put £10 of fuel in @ £1.16 a ;litre, and both times only managed 20-23 miles!
so if im right its about 12mpg.
the fuel guage isnt that great, but is thre anything obvious why i wuold be gettin rubbish mpg?
ive not been thrashing it either, pretty gentle country road driving, no traffis or towns.

definitely something wrong with yours then as I was getting that and I had a loose exhaust joint on the centre box, the downpipe gasket was shot, air leak from the AFM to TB hose and also a couple of other things that I can't remember..

[pirate952]

have you read my last post?

[handpaper]

300 miles is about right from a full tank, from brimmed to the reserve light coming on.
Tappets are adjustable, look in the Articles section for instructions on doing this. A clicking sound may remain, this is the injectors which are a bit noisy.
The manifolds and downpipes may be different as there are two sizes. My (facelift) 320i had the larger, yours may not. If you have a three-piece system with a joint between the manifold and centre box, a 325i system can be fitted from this joint.

[casper8r]

300 miles is ok from a tank driving at the speeds you describe on your very own private 4 lane motorway. I get about 350 but then I drive at 70 since I'm not among Her Majesty's family/friends and I don't have a license to kill.