turbo'S'

Hi there,
I have just got a 525d Touring and the urban fuel economy is worse than I expected. Its showing 20.4mpg when being driven easily!
Is this the norm or should it be better. Maybe something needs looking at?
I had a car once that required the settings to be reset when new tyres were fitted as this would effect calibration- is this the case with the E61?

Thanks in advance.

xBMWx

Some more info would help us help you...
- What month+year is your 525d (i.e. what engine version of the 525d you have)
- Manual or auto
- short / cold drives in the city only, or also motorway driving

Your location details will also help in general. You do this by hitting My Controls at the top of the page, then click on Edit Profile Information on the left handside of the page, and then enter the Your Location details.


My current 6/2005 530dA had pretty poor fuel economy in the city, somewhere around 10,5-11L/100km. I've had it remapped and its now around the 9L/100km, which I believe is somewhere around 32mpg. Still not at the 7,5L/100km I was getting out of my LCI 2008 525dA, but better than before. NOTE: this includes some motorway driving as well, but 80% urban.
The older pre-LCI diesels are good on the open road and motorway, but in the city I was also disappointed with the fuel economy and I've read in a number of forums that this is unforetunately the way it is. The new (LCI) diesels are however much much better, especially when you compare automatics, the LCI being far more efficient and effective at getting the power to the wheels.

turbo'S'

Thanks for that.
It is an auto 525 2.5litre Post september 2005 car. Driven short trips by wife to school and shops.
I have driven it longer distances but it is new to us and not had a real run yet.
I noticed it had that diesel smell that someone mentioned at start up through the vents and wondered if it might be this manifold issue? Its sounds reasonably loud on idle but that's maybe the way they are. Its not loud in the car!

I have only just changed my wheels to 19" and not sure if I have to reset the I drive or whether it works it out itself?

I'm in Edinburgh, Scotland.

Nice car BTW.

Stephen F

Hi, There are a couple of things I would check/replace after spending a year or so solving the poor fuel economy on our now sold 2004 E61 530D.

Firstly ensure the air intake is not blocked with debris (remove air filter to check) - will be full of leaves etc if not recently replaced

Secondly Check the engine is reaching normal operating temp (do a search on here there is a big topic about this) Our car was not reaching full temp due to the EGR thermostat and main thermostat being faulty (replaced under BMW warranty) This made a huge difference to economy.

Once you know how, it is easy to display the coolant temp on the dash and self diagnose if the thermostats are faulty as the car will take ages to warm up and not maintain normal temp of 90 - 92 at motorway speeds causing the ecu to supply more fuel as it will be in warm up mode all the time.
This in turn can prevent the DPF regeneration cycle from operating correctly and can cause the DPF (diesel particulate filter) to become clogged

Third - Have the oil seperator replaced - again if not recently done it can get blocked and cause long term damage and excessive oil use.

Once the above work was done our car went from 28mpg to 35 mpg on longer journeys and even around town never went below 31 over several thousand miles.

No harm in trying some premium diesel and giving the car a good work out! - ours was much smoother on the expensive diesel

chesney72

Just out of interest are you reffering to the oil breather? Top of engine between the intake and the fuel rail? When I bought the car I replaced this, cleaned the MAF and cleaned out the EGR.

Agree with you that premuim diesel somehow makes the car sound smoother.

I get about 42mpg out of an average tank but as soon as you start with school runs and city driving then it drops massively. Never seem worse than 36mpg from a tank but we live in the sticks so even the school/nursery run we don't get stuck in traffic. Thankfully our eldest is in the village school now so he gets walked to school, that must be saving us 5mpg !!!

Also agree that a diesel needs a good thrash every now and again rather than pottering about clogging it up!

chesney72

To access the hidden menu I found this procedure from another post on here. I didn't need to start my engine though!

http://www.kolumbus.fi/jkorkala/bmwdebug.html