[jinjur]

Dude......34 mpg is good for a fast hatch or sports car.....not for an oil burner

My Civic gets around the same and would demolish the Bee Em

[ElegantSpoon]

It all depends on the type of driving you do. I've had a Audi TT 25mpg, BMW Z4 24mpg, Mini Cooper 28mpg, and the 320d is 34mpg. Plenty of people get much better mpg on all of those cars but I never managed it and I don't see the big problem.

[beemerbird]

Your sort of mpg is not good, but you already know that, 34 mpg is what I used to get out of re-mapped 335d..........I would certainly expect to get significantly more out of a 320d.

I know a bloke who has an '07 plate 520d coming up for 70k miles (he's a rep) and the car is going in for a second set of new injectors following his second bout of poor fuel economy.

I am no engineer but have heard it muted that in order to obtain such official and 'claimed' fuel economy figures in the first place, part of that process may be to run the pressure within the injectors quite high, which may sacrifice longevity of said injectors. I don't honestly know.

From what you've said your wife Helen appears to drive longish distances which should be producing decent mpg returns, especially in an oil burner.

I'm currently getting 19 mpg if that makes you feel any better..............just trying to make you feel better.....hopefully!

[teemuturunen]

If fuel economy raise... probably the catalysator/DPF FILTER hevily glogged.... it will raise fuel consuption and exhaust back pressure... IT will not open with driving pedal to the metal!! have to drive over 80km/h 30min stable pedal or cruise control (DDE/digital diesel electronics will then automatically activate the DPF REGENERATION/cleaning function ... (sorry for my english) and some of ecu remaps will fuck up this function... that's why i would newer remap my car(diesel)... powerbox (p-tronic) is much better

[MEGA]

No one has mentioned MAF yet.

BTW my 320d is currently sat on 23mpg over the last 200 miles.

So you think you've got problems

If you get a definite answer here, let me know I'm sure I've got the same issues.

car is due a service in March anyway. Will get them to replace the MAF under warranty if I can...

[mikeysix]

by the sounds of the replys all of the 163's remapped are getting roughly the same consumption. I never use the car during the week, the missus uses it for nippin round the town, not ideal but thats what a cars for. Mine too is remapped and its currently sitting on 34.5. Before it was mapped it usually avg 38-40 so its not really a great loss. When I do use it at the weekends and I dont have the wee one I will give it a blast. I do hear where the op is coming from. My mate runs an A3 55 plate 2.0 litre denz and its constantly mid to high 40's around town. I wont be buying a diesel again, I do love the torque and really want a 335i but I think a nice 6 cyl 3 litre petrol would be fine. My previous e46 was a 2.5 petrol and it avg 30 mpg around town and sounded lovely

[HighlandPete]

If there are no fault codes and you don't sense any performance issues, I'd seriously be looking at the engine hot running temperature.

As we don't have coolant temperature gauges we can be ignorant of the hot running temperature. It is a known issue that fuel economy can be dire in our diesels, if the coolant temperature is low. BTW, you won't be the first to have this issue and once sorted the economy goes back up to average. Likely the thermostat, coolant temperature needs to be interrogated.

One other thought, how good is the remap? If the fuelling map is poor, that could explain it all.

HighlandPete

[jinjur]

Pete,

Thanks for the suggestion on the temps.....will look into that

The economy was dire before the remap.............it was no different after at all.



Regards
Andy

[lons]

Car's definately not right

Mines a 177 sept 08 but I do only 5 - 6k pa no motorway and max run on dual carriageway is 15 miles.
Longest journey I ever do is 25 miles and loads of very short trips and stop start.

I consistantly average (albeit via car computer) is high forties in summer - mid forties in winter and it's been consistant since I bought it.

I don't hang around either and try to make the most of accelleration available.

You need to get it sorted - the 320d is a pretty good engine imo
It might cost a chunk of £ to diagnose it but you'ld get that back in fuel consuption if you can fix it.
Gonna lose money if you trade in anyway surely?

[chris330D]

Fuel consumption is a really tricking one to pin down as so much depends on the driver, the conditions and the type of driving. I have owned both a 320d (163) and a 330d (231). On my daily commute the 320 averaged 30-32mpg. The 320d on the same commute give 27-28mpg. The difference is on a long steady run. These cars don't like stop-start driving and the mpg climbs on smooth steady speeds. My last car, the 320d, was the same as yours on a smooth motorway run (80ish) it would do 40-45mpg. Can't help buth think the remap won't have helped?

[jinjur]

Ok.....map now off.


Slow as sh@t and no notable difference in economy.

Averaged 36mpg on the way there (about 20 miles, 90% motorway)

Averaged 37mpg home.

Computer was reset at the start of each.



Please note......I was driving like a complete wuss.....cruise control @ 70mph all the way.

No overtakes or WOT at all.





Dung.

A

[F104]

Only other things i can think off:
- does the engine feel ok and can you get top speed out of it? If not i would investigate if you get correct turbo boost
- as someone said check the thermostat. Not for running hot (the light would come on, and the fan way before that), but for running cold. If it's stuck open the ECU might try to heat the engine up by increased fueling. Start with a cold engine, let it idle and check the hose to radiator. It should stay cold and when you pinch it you can feel if there's flow.

good luck

[jinjur]

Ok......

Lets try an reason this out.

My mapper dude reckons this is no way a software thing and even he thinks the economy is poor. That leaves mechanical items.

He also thoughtthe engine was indeed noisy....this is after the de-map

So, I would like to know the tests for the following items to see if they are faulty or not:

1. MAF sensor
2. Diesel Injectors
3. Turbo
4. Variable Vanes

Do our cars also still suffer from the breather gunging up or was that only the older bee ems?

Would really appreciate some BMW tech advice, I really have no faith in our dealerships at sorting problems like this out

Regards
Andy

[Ti Rich]

I would do the easy things first:-

No 1. The MAF sensor - In my opionion these should be service items as they normally below par by about 40k miles. At 80K i bet yours is shot. One of the ways to tell is how the boost comes in. If there is nothing at low rpm and then a wack at about 2200rpm this is a sign the MAF has gone. The MAF sensor governs the fueling at low rpm and small throttle opening. Once the turbo spins up more of the fueling is controlled by the MAP sensor. So if the MAF goes, or gives an incorrect reading fueling is effected most when trying to obtain good MPG.

No 2. Change thw PCV valve. Again at 80K this might be worth changing especially if it is early type that has a toilet roll type filter. The later vortex type don't give as many problems. Not sure then they change from one type to another. This is the breather filter and can cause rough running.

No 3. Check tyre pressures again (sure you have done this)

Given that you car is making good power with the remap I doubt it is a turbo problem.

My money is on option 1, good luck.

[F104]

Thanks - I learned something - never knew why we have both MAP & MAF. Would agree with it being number one cause then. One needs one hell of a PCV/CCV problem to cause this fuel difference, which could only? be caused by a worn out engine which is not in line with it pulling ok. And such problem would result in burning oil & oil consumption

[Ti Rich]

I was saying to change the PCV due to the rough running, I agree this shouldn't effect the MPG.

[Taylor]

mines a 163 im getting 34 mpg so it says, not been on a long run for a while and im pretty heavy on the accelerator always refueling at morrisons £20 every few days then the fuel warning light flashes back up....

[jinjur]

Again mate......34 mpg is wank.

So, I disconnected the MAF sensor there and took it for a drive.

It did NOT feel any different at all.

Does that point to the MAF being borked?


Also, I gingerly opened the oil filler cap when the engine was running and there was alot of blowing out through the filler happening.....is that normal on these enignes?

I know i can open the cap on my wee Civic and there is more or less no blowing out of the opening. I appreciate that this is a petrol though.

Is anyone confident that the breather on these cars is the new type that doesnt clog?

Regards
Andy

[ElegantSpoon]

It doesn't sounds like the MAF then. If your MAF was faulty you should feel a performance increase.

[jinjur]

Odd....

My logic dictates that if I disconnect something that is working and helping the engine I would feel the engine suffer

Likewise, if its not working, then there will be negligible difference whether it is connected or not.

Does that not make more sense?

Regards
Andy

[ElegantSpoon]

No a faulty MAF normally causes a loss in power. If you disconnect the MAF the ECU goes to a default setting and will restore performance. Its seems to be a very common fault not just on BMW but Audi's as well

[ElegantSpoon]

Here you go

Q3: WHAT ARE THE SYMPTOMS OF A FAULTY MAF & HOW CAN I TELL IF IT IS FAULTY?

A1: Loss of power throughout the rev range, can indicate a dead maf (possibly even worse at low rpm).

A2: Loss of or absence of low down power (below about 2100rpm - i.e. before the turbo comes in) tends to indicate an out of spec maf.

A3 : Not too bad low down, but a reluctance to rev past 3800rpm indicates dead maf OR disconnected maf OR bad connection.

TIP Unplug the MAF plug and go for a drive - you'll soon notice a difference if your maf is faulty or out of spec! You will find that low down driveability is vastly improved, but max torque and turbo boost is often reduced somewhat and there is an unwillingness to rev past 3800-4000rpm. If you get gains throughout the rev range then your maf is seriously ill, but still fixable with a Mafam unless completely dead. (rare)