[rimz]

Hi, i have a 2007 320d e90 se. 114k miles, serviced and looked aftered, i only drive it to work which is a 16 round trip dual carriagways. I put in 40 pounds of shell fuel only at 134.9 and its only showing 30.3 mpg, i always reset the trip and it gets me about 190 miles to £40... Tyre pressure checked, water and oil regulary too, no smoke or noises from turbo, no judders from injectors, have not tried the diagnostics yet. Any thoughts on what i can do or check? Thanks

[HighlandPete]

Originally Posted by rimz

Hi, i have a 2007 320d e90 se. 114k miles, serviced and looked aftered, i only drive it to work which is a 16 round trip dual carriagways. I put in 40 pounds of shell fuel only at 134.9 and its only showing 30.3 mpg, i always reset the trip and it gets me about 190 miles to £40... Tyre pressure checked, water and oil regulary too, no smoke or noises from turbo, no judders from injectors, have not tried the diagnostics yet. Any thoughts on what i can do or check? Thanks

What is the ECT (engine coolant temperature)? Have you checked it through the hidden menu? Should be around 90C, common to see poor mpg due to low ECT, caused by failing thermostats.

HighlandPete

[rimz]

No,havent checked that, is there a step by step guide i can follow?

[mammoo6]

Here is the guide here mate... easy enough to get into... i do it via option 2.

Once you Unlock it, your looking for menu 07.00

http://e90.wikifoundry.com/page/BC+hidden+menus

[doughboy]

30mpg seems ok for such a short commute, the engine will be barely warmed up ever.

Go for a 100 mile steady mway cruise and see what you get.

Is it an auto or a manual?

[Jase 320d]

You need to check engine temperature

I suspect a duff main thermostat / egr thermostat and the car will be running at 70 degrees

[Digitalize]

The engine will be warm in about 2-3 miles, but I do suspect faulty stats, and an EGR that probably could do with a good clean.

[rimz]

Thanks to all, will get on the menu.

[rimz]

Just checked after unlocking the menu... The thermo on 07:00 was reading 78C. Is this normal?

[Pumper]

Originally Posted by rimz

Just checked after unlocking the menu... The thermo on 07:00 was reading 78C. Is this normal?

Fully warmed should be ~90C. Mine takes ~15-20 minutes of driving to get to 90C-91C.

[rimz]

I have done a motorway stretch of 80 miles and hot 55mpg on display before, I drove it for 5 miles before checking it, it was driven earlier too, prior to me checking. Is 78C low and how much is a thermostat cost?

[doughboy]

Originally Posted by Digitalize

The engine will be warm in about 2-3 miles, but I do suspect faulty stats, and an EGR that probably could do with a good clean.

No chance 2 or 3 miles. More like 10 miles, or 15 minutes minimum.

A steady water temp is not an indicator of a warm engine. Oil temp is the true indicator. A stable oil temp means the engine is warmed through.

My current car has digital water and oil gauges, the water can be on 90 in a few minutes while the oil is still on 10.

10 miles min gives a steady oil of 105, same in the 335i too.

OP, i still say 30mpg is ok for a short commute, what figure were you expecting?

My missus has a 1.6 mini and that barely does 26mpg on a 5 mile run.

[Digitalize]

I get 36mpg in bath, which is all hills.

[Jedimindtrix]

My wife's gets low 30's when dropping off the toddler for nursery, popping out to the shops/gym etc.

But on a motorway run the MPG is 45+.

OP I think you car is running ok but i have a spare EGR in my garage that I could sell to you, I ordered it by accident 2 months ago.

[rimz]

I think its low because my bro has a 320d e46 and he is on 36.9 mpg and his is a private taxi, my old e46 320d last year was giving 35mpg, i owned a vw passat 130bhp 2004 1.9 tdi which was giving 60 miles to £10.

[chrissyw]

I've recently bought an 06 320d and I haven't been 'blown' away by the MPG. I stuck 30 litres of diesel in and got 310 miles out of it but I mainly sit at 65mph on a dual carriageway.

Checked my coolant temp and it is running at 80c after a 50 minute drive.

Wacked my tyre pressure up as it was very low.

The EGR stat is the cheapest and gets stuck open, which causes poor MPG - £30 from BMW. The main stat is a bit harder to change and is about £50. You need new coolant too.

[Digitalize]

Coolant temp is too low, an EGR stat is a simple fix but might not get it fully to temp.

[Jase 320d]

Mine sat at 80 degrees

Changed EGR stat and still 80 degrees!

Had to change the main stat to get it upto 90

[chrissyw]

My car is still under warranty, i'm just not sure how to go about saying there is a thermostat problem without getting fobbed off?

Are there any other symptons of a stat on its way out?

[Digitalize]

I had this issue, after arguing lots I got the main stat changed.