E46 330ci restricted performance (re-posted)
Discussion
I’ve got a BMW 330ci “E46” and for quite some time now I’ve noticed that it’s performance seems a bit limited.
It’s been to BMW a couple of times and they cannot find fault with it.
She starts up fine and the engine has never missed a beat. She gets through about 1 litre of oil every 1,000 miles which I’ve never had on a car before and which I think is excessive, but I’ve been told by BMW themselves is normal for that type of engine.
The symptoms are as follows:
Once the engine is all up to temperature and you can start to give it the “beans”, when accelerating it seems to “bog down”. There’s a nice burble from the exhaust but it doesn’t really go any faster, however as you start to ease off the accelerator pedal it seems to catch up with itself and the acceleration seems to increase.
I’ve looked at various forums and people with similar restricted performance issues have suggested either a dirty or broken MAF sensor, however they also mention that their restricted performance was accompanied by poor starting / stalling vehicles, however like I’ve said mine runs fine, its only when accelerating that I notice a problem.
I’ve carefully removed the MAF sensor and cleaned it with both electric contact cleaner and carb cleaner but this has made no difference at all!
People have also suggested I unplug the MAF sensor and see if the performance improves, as they say the car will revert back to a factory setting. I’ve tried this and can’t really notice any difference.
BMW have quoted me £340 to change the MAF but as you can appreciate without knowing that it is definitely the problem I’m not keen to do this at the moment.
Any help would be much appreciated.
It’s been to BMW a couple of times and they cannot find fault with it.
She starts up fine and the engine has never missed a beat. She gets through about 1 litre of oil every 1,000 miles which I’ve never had on a car before and which I think is excessive, but I’ve been told by BMW themselves is normal for that type of engine.
The symptoms are as follows:
Once the engine is all up to temperature and you can start to give it the “beans”, when accelerating it seems to “bog down”. There’s a nice burble from the exhaust but it doesn’t really go any faster, however as you start to ease off the accelerator pedal it seems to catch up with itself and the acceleration seems to increase.
I’ve looked at various forums and people with similar restricted performance issues have suggested either a dirty or broken MAF sensor, however they also mention that their restricted performance was accompanied by poor starting / stalling vehicles, however like I’ve said mine runs fine, its only when accelerating that I notice a problem.
I’ve carefully removed the MAF sensor and cleaned it with both electric contact cleaner and carb cleaner but this has made no difference at all!
People have also suggested I unplug the MAF sensor and see if the performance improves, as they say the car will revert back to a factory setting. I’ve tried this and can’t really notice any difference.
BMW have quoted me £340 to change the MAF but as you can appreciate without knowing that it is definitely the problem I’m not keen to do this at the moment.
Any help would be much appreciated.
i have a friend with a 330ci cab and it seems slower than my other friends 323ci coupe. performance stats suggest it should be totally the other way but reality says otherwise. if your car indeed has a problem, then i would suggest his would be the same problem as it seems a perfect runner and makes a decent sound but just is not as fast as the 230 or so bhp would suggest. His car also uses a fair amount of oil. (within bmw tolerances, what a joke)
Edited by rb5230 on Monday 14th June 13:21
If it is the maf sensor (usually faulty ones won't show up on a code read) just disconnect it, it will go to the default setting, then drive the car, if it feels better then it'll point to the fault, the poor starting/idling you mention is usually a faulty cam sensor.
Most other things will show up on a code read though a split hose will cause problems, doubtful to be this at it causes idling problems.
Check the twin exhausts and make sure the flap in the 2nd exhaust isn't stuck closed as this can cause a problem at higher revs.
Hope you get the problen sorted.
Most other things will show up on a code read though a split hose will cause problems, doubtful to be this at it causes idling problems.
Check the twin exhausts and make sure the flap in the 2nd exhaust isn't stuck closed as this can cause a problem at higher revs.
Hope you get the problen sorted.
Edited by Martyn D on Monday 14th June 20:20
Worth checking out the DISA air intake flap, when this started failing on my Z4 the engine had quite a loud warble and pulled ok but nowhere as crisp as when I fitted a new working replacement.
Its on the air intake side of the engine near the top, big plastic device with one electrical plug and a moving plunger which actuates a flap inside the engine intake to vary the air flow characteristics.
With the engine idling does the unit rattle, remove the electric plug and does the rattling stop. Go for a drive with and without it connected and see if it make a difference above 4k rpm.
Good luck!
Adam.
Its on the air intake side of the engine near the top, big plastic device with one electrical plug and a moving plunger which actuates a flap inside the engine intake to vary the air flow characteristics.
With the engine idling does the unit rattle, remove the electric plug and does the rattling stop. Go for a drive with and without it connected and see if it make a difference above 4k rpm.
Good luck!
Adam.
Cheers for all the responses guys, really appreciated.
I've done some research on some of the suggestions preople have made, but almost all of these seem to be accompanied by bad idle / rough running etc. however the engine on my car runs fine its just down on power under acceleration!
Was wondering if it was something like a blocked crankcase breather valve or a bad throttle position sensor, which may not necessarily thow any error codes when read by BMW diognostic machine? Would these cause loss of power without the engine running roughly???
I've done some research on some of the suggestions preople have made, but almost all of these seem to be accompanied by bad idle / rough running etc. however the engine on my car runs fine its just down on power under acceleration!
Was wondering if it was something like a blocked crankcase breather valve or a bad throttle position sensor, which may not necessarily thow any error codes when read by BMW diognostic machine? Would these cause loss of power without the engine running roughly???
Podie said:
4rephill said:
anonymous said:
[redacted]
+1 
, BMW say as little as 600 miles per litre of oil is within specification.2000-2003 E39 5 Series
2000-2006 E46 3 Series
2003-2005 E60 5 Series
2003-2005 E63 6 Series
2000-2005 E53 X5
2004-2005 X3?
2003-2006 E85 Z4
2000-2002 E36 Z3
2001-2004 E65 7 Series
Yep the 2 x M54 I've had (x5, 330ci) both like a drink (1litre in 1000miles for the x5) much more so than the m52 version. BMW say it is a trade off between internal friction (and hence economy) and oil consumption, probably BS tho ! I always take oil consumption as a sign of a knackered engine, probably best I don't get an e39 m5 then !
Ian
Ian
Gassing Station | BMW General | Top of Page | What's New | My Stuff