Poor MPG
- Thread starter ofis_2311
- Start date
Liverpool
In general, a normally-driven 3.0 litre should get over 400 miles to a tank (even an ///M can get over 300 miles) on a run.
However, short trips when cold will give you considerably less MPG as will doing the traffic light grand prix at every opportunity (i.e. my M can get 30 UK mpg on a run, or 17 UK MPG in stop-start traffic around town).
Automatics will also deliver slightly less MPG than manuals.
However, short trips when cold will give you considerably less MPG as will doing the traffic light grand prix at every opportunity (i.e. my M can get 30 UK mpg on a run, or 17 UK MPG in stop-start traffic around town).
Automatics will also deliver slightly less MPG than manuals.
ofis_2311 said:
I used a 3.0si Coupe as a daily for almost 2yrs. Generally speaking I got the following as my fuel economy:
- Normal motorway journeys sitting at a steady 70mph - 38-41mpg.
- Optimal conditions and being economical on the motorway - 48mpg.
- Combined - 30mpg
- Weekend trips (120miles of motorway and 80 miles or so of hooning) - 23-25mpg
- Hoons - 17mpg.
- Town only - 23mpg (plenty of unnecessary acceleration and rev matching because cool sounds).
Imperial mpg, obviously.
Pure highway, 70 MPH with cruise control, 6SPD, ~32-34 MPG (US gallons) on 93 octane fuel . I drove the car across several states when I first got it so I had opportunity to see what the car does MPG-wise on a long, uninterrupted trip.
I get less fuel economy with 91 octane (thanks California) and city / start-stop driving.
But the fuel tank seems very small, I could almost see the fuel needle move as I was driving, very odd. Amusingly Jeremy Clarkson mentioned the small fuel tank in the Top Gear review of the S2000(Clarkson) / Z4(Hammond) / Cayman(May).
I get less fuel economy with 91 octane (thanks California) and city / start-stop driving.
But the fuel tank seems very small, I could almost see the fuel needle move as I was driving, very odd. Amusingly Jeremy Clarkson mentioned the small fuel tank in the Top Gear review of the S2000(Clarkson) / Z4(Hammond) / Cayman(May).
deltasierra
Member
2.5si roadster 6 sp auto 33-35 mpg long term average, according to the dash display, I’ve never cross checked that with actual miles driven but it always seems pretty economical to me.
could be all sorts of reasons, read codes for obvious faults. Carry out a fuel consumption run - you should be able to see instantaneous consumtion as well as trip consumption. Check / change the aircleaner? Put some injector cleaner through it?
Vanos solenoids?
Take your big right boot off and drive in socks, Done floor itall the time despite the temptation - ...........
Vanos solenoids?
Take your big right boot off and drive in socks, Done floor itall the time despite the temptation - ...........
lucasxdiniz said:
This is really helpful.
I don't drive my car everyday or do many long drives in it. I usually pop to the gym in it after a work or grab groceries. 3-4 mile round trip most evenings. My average MPG is low 20's. On a weekend I might go for a hoon, or the odd 50 mile round trip or so on the motorway to the office. etc
Not sure that's good or bad?! I feel like even on the motorway I probably get 25-30. A full tank probably says about 300miles on my dash
r3vmatch said:
That's equivalent to around 38-40 mpg in UK gallons which seems pretty good!
But you're right about the tank being small. It's only 55 litres compared to the 63 litre tank in my 3 Series. It's even more annoying since I bought my MC, because it likes a drink!
I have a 2005 2.5i and I'm getting about 21 mpg in the city and maybe 27/28 on the highway. I've felt that's pretty low, but my mechanic says it's about right. Mine's a 5-speed auto and I drive it moderately conservatively. I'm in the US and using 91 octane.
A
Anonymous
Guest
Check for a vacuum leak. When I fixed my oil cooler gaskets mpg went up so much it, I couldn’t believe it. Check oil cooler / oil filter housing gaskets, as well as valve cover gasket. Leaking air into the system will use more fuel and run less mpg
Take a look at the fuel trims using a decent scan tool, high trims c an be as a result of air leaks that the exhaust sensor is picking up as unmetered air that has not been measured by the Maf sensor. Air leaks in the engines vacuum system after the Maf will cause the computer to see this as a lean mixture and try and compensate by adding fuel at the injectors to richen it up. It will continue to add fuel until its introducing 20% more fuel before it realises something is wrong and it will eventually light the EML to draw attention to the fault and set codes in relation to the fuel trims being high. MPG will be affected and you will be visiting the fuel station frequently.
Air leaks can usually be pinpointed by doing a smoke test, some can be hidden and easily missed doing a visual check. Splits or holes in the intake rubber bellows are the most common but also check the rear underside of the intake manifold where there are rubber blanking caps that perish and fall off allowing air leaks. If you have a dipstick also check the O ring in the dipstick tube for any leaks. Smoke is the best way to find small leaks. Have seen plastic cam covers develop cracks and allow air in as well as oil out, smoke found the leak in one I worked on.
Air leaks can usually be pinpointed by doing a smoke test, some can be hidden and easily missed doing a visual check. Splits or holes in the intake rubber bellows are the most common but also check the rear underside of the intake manifold where there are rubber blanking caps that perish and fall off allowing air leaks. If you have a dipstick also check the O ring in the dipstick tube for any leaks. Smoke is the best way to find small leaks. Have seen plastic cam covers develop cracks and allow air in as well as oil out, smoke found the leak in one I worked on.
