[stefank]

As I mentioned in title, I doubt my fuel consumption is few liters per 100 km higher than it should be. Only on cruise control I can get something like between 8-9 L/100 km, on sporty driving outside of city it is like between 10-12 L/100 km, and in the city it whoops for 14+ liters no matter how I drive (if I measure it getting stuck in traffic with many idles and hard foot on gas pedal, I can get up to 18 L). With very light traffic and very light leg on the pedal, I can get maybe around 13 L, not a chance it can be lower than that.

My car is E93 2008, 330d M57N2, ZF6.

My nozzles are perfect (all 6 are around zero on diagnostics), no errors on computer, all runs just fine.

Today I got MAF controlled and cleaned, we read 478 mg on idle while for target value it says 449 mg (tested while driving too, it was about +100 mg more than target value), after cleaning we got that target values so I suppose it is fine now, my mechanic told me not to change it. Car runs smoothly now, no more causal jerking in first gears (it's automatic, I guess mixture confused the gearbox).

I haven't tested fuel consumption after this intervention yet, but if it doesn't get significally better, where to start? MAP sensor maybe? Is it this at number 7 on this diagram?

http://www.bmw-etk.info/parts-catalo...77/13627792260

Also, I have read somewhere on the forum about pressure converter and low mileage, is that this little thing on the number 1 on diagram?

http://www.bmw-etk.info/parts-catalo...170/11/11_2336

[335stoner]

number 1 is an egr solenoid. pressure converters are on the turbo side of the motor.. follow the mess of vacuum lines they lead to the pressure converters..

carbon build up can cause bad fuel economy

[stefank]

Thanks...

I was just driving around town for a while, I think it is a bit better with cleaned MAF, but it isn't ideal yet.

There is no carbon build up, EGR looks clean, checked it visually...DPF is fine too.

My mechanic disconnected EGR few months ago for a test for something else (we thought it is bad, but it wasn't), but I think I had like 1-2 liters lower consumption with EGR off (and check engine on, lol). But EGR seemed ok, it is not clogged, it opens/closes fine, vacuum was working...so we put it back in function, as I had DPF clogging problem without EGR connected (it cleaned itself very fast after that, on highway, DPF measurement showed only 7 mbar on diagnostics after regen, which is ideal). That time I had a problem with glow plug unit, when I replaced it, DPF regens continued to work immediately.

So EGR solenoid might be a good start, if I think better. That solenoid is actually an electro-switch for EGR valve, right? Do you have part number or diagram, so I can find it online? Is it part number 01 on diagram on this link:

http://www.bmw-etk.info/parts-catalo...170/11/11_3877


Is there any reliable way to check if EGR solenoid and turbo pressure converter (is that MAP sensor?) are making problems, without error codes?