Bmw 640d f13 Poor Mpg

[Bmw640dude]

Hello I wanted advice on how to improve my mpg or what may be the issue. My 2013 F13 is averaging 22 mpg on eco-pro/very sensible slow driving. I put in 5 gallons of fuel and have done just about 100 miles averaging 20MPG(City and dual carriageway 50mph). The car had a service last month. There are no warning signs on the dashboard And nothing displaying any signs. 70k miles. Anyone can give me advice please and what could be a problem or what to do.

Thanks.

[Huskyman]

That’s really bad. I’ve got an f11 with the same engine and I get 34mpg and I drive mine quite hard.
What’s the state of the tyres? Are they at the correct pressure?
Has the car suddenly started drinking fuel or is this a gradual thing that’s happened I’ve time?
Has the car been in for the EGR cooler recall?

[Bmw640dude]

Hi

Tyres are brand new! With 500 miles on them, Service done last month, car is in tip top shape! It was used as a spare 2nd car so in last 12 months only driven 4000 miles. I had it repainted in September from Red To purple and now im making use of the car as a daily however due to the mpg im Reluctant to continue using it. The only sign on the dashboard is, “check drivetrain” I thought this was due to the suspension springs on the rear which were broken and had been changed last month too but the error message never went away.

Mpg seems like it went slowly down gradually as previously it was doing 35.

[Huskyman]

Bmw640dude said:

Hi

Tyres are brand new! With 500 miles on them, Service done last month, car is in tip top shape! It was used as a spare 2nd car so in last 12 months only driven 4000 miles. I had it repainted in September from Red To purple and now im making use of the car as a daily however due to the mpg im Reluctant to continue using it. The only sign on the dashboard is, “check drivetrain” I thought this was due to the suspension springs on the rear which were broken and had been changed last month too but the error message never went away.

Mpg seems like it went slowly down gradually as previously it was doing 35.

Check drivetrain means that there is a probable fault with the engine. You didn’t mention if you’ve had the EGR cooler recall done. The fact that it is doing 20mpg sets some very loud alarm bells ringing. Is the engine oil level staying constant or increasing? Get the codes read ASAP and start from there.

[Bmw640dude]

No idea to be honest never had a recall letter so probably not and ok will check the codes out never thought of Diagnosing it

[cossy400]

Has this got a temperature gauge?

If not get the secret menu up and see what the temps are doing as if they are shot the the MPGs will suffer.

[Ninja59]

Get the codes checked check drivetrain can cover a number of sins.

It is probably down to that.

Also the temperature gauge is for oil, secret display can give real-time coolant temp. Should be 88 plus or minus 2 really.

[S8QUATTRO]

Bmw640dude said:

No idea to be honest never had a recall letter so probably not and ok will check the codes out never thought of Diagnosing it

Ring the dealer with your reg. will tell you in minutes if it needs the recall doing.

[Monty Python]

It's city driving that kills MPG. My 340 can easily manage ~20mpg if I do a lot of stop-start driving. What do you get at a constant 50mph?

[_Hoppers]

S8QUATTRO said:

Bmw640dude said:

No idea to be honest never had a recall letter so probably not and ok will check the codes out never thought of Diagnosing it

Ring the dealer with your reg. will tell you in minutes if it needs the recall doing.

The MOT History website should also tell you

[thatdude]

City driving, as has been said, will really kill the MPG. Idling means using fuel for going no-where, and the constant accelerating means you're always throwing in more fuel than you need for a given speed becausw you'e trying to get faster. Ok, sorry for being a bit partnising thre, but you see what I'm getting at. How about the journey length? Short journeys are also going to kill MPG as the engine stays in the richer cycle for mroe of the time the engine is running.

Couple of things to check then: engine coolant temperature - does it get up to temp? If it doesnt, then it'll be running n that enriched map. How about things like binding brake calipers, tyre pressures (check them yourself!) and wheel alignment? Admitidely unless the alignment is well off and you;re going down the road sideways this wont cost you much.

Does the car feel more sluggish to you at all?

Wat was done on the last service? Any idling issues (i'm thinking of air leaks now that could cause the engine to compensate for that by running richer)?

reset the MPG meter, go for a good steady run on a motorway at 60-70 mph , see what it averages out to after 30-45 minutes of driving.

[Jiebo]

City driving still returns decent MPG in mine. Ive never had below 25mpg and that’s driving it very very hard in stop start. Ordinarily I get a solid 28mpg in constant stop start traffic in London, 30mpg if its eco pro and driven very carefully. 20 isn’t normal.

[Bmw640dude]

I got a diagnostic check and it says
27b900
Exhaust pressure upstream of the turbine
244c00
Boost pressure control to low
290a00
Air system to to EGR mass flow plausibility. Air mass to high and and high boost pressure.

[gizlaroc]

I would do a smoke test and check for leaks, maybe a pipe or could be a cracked manifold.

Your car has gone into default mode and is over fuelling due to boost leak.

[gizlaroc]

You can get someone to rev it and see if you can see/smell exhaust gases anywhere, if not then spray water all over the pipes, inlet manifold and see if you see any bubbles.

If not joy get garage to do a smoke test.

[Huskyman]

Bmw640dude said:

I got a diagnostic check and it says
27b900
Exhaust pressure upstream of the turbine
244c00
Boost pressure control to low
290a00
Air system to to EGR mass flow plausibility. Air mass to high and and high boost pressure.

If you haven’t had the EGR cooler recall done I would get the inlet manifold checked for damage as the EGR cooler failure can take this out. You need to get this checked ASAP.

[gizlaroc]

The other thing to check, does it smell of exhaust fumes under the bonnet?

[mekondelta]

Cruise control doesn't help fuel consumption even in eco pro mode.