BMW still not running well..... advise needed.

[Gammelhagger01]

Hi Guys..

I have a 2001 BMW 330ci convertible with 120tkm on it.
Since I bought the car last year I have spen a fortune trying to get it to run as it should.
My problem is that it can loose power when warmed up. Not always though.. ( No fault codes!! )

I have done all the typical E46 stuff....
New:
MAF,
Vacum lines.
CCV
DISA
ICV
Crank and cam sensors
Gas pedal
Throttle body
Vanos seals and O rings.

When cunducting a smoketest everything is fine..

All I have done has helped...but the power delivery is still not consistant. If I start accelerating by increasing pressure on the accelerator gently, the car kind of drags.... but if I lift my foot and then press the accelerator hard, the power is there and it does not drag...
Another very strange thing is that after driving for a while,( a few days ) it gets harder to shift gears ( manual ). It will shift, but it feels like a very badly worn gearbox that is out of sync. If I reset the ECU by disconecting the battery, the car shifts like a new car for a while ????

I have not yet:
Changed fuelfilter ( fuel presure regulator is build in ).
Changed the fuelpump.

The car idles perfectly when cold and hot and it has no cooling issues.

Any ideas ??

[Dannbodge]

For the gearbox, if it's an auto get the oil and filter changed and the box reset, if manual replace the linkages and change the oil.

As for the power delivery? I have no idea.

[nitrodave]

Dannbodge said:

For the gearbox, if it's an auto get the oil and filter changed and the box reset, if manual replace the linkages and change the oil.

As for the power delivery? I have no idea.

defo do this, changing the fluids on a high mileage car can really help.

have you tested your vanos solenoid?

[Ozzie Osmond]

Gammelhagger01 said:

Any ideas ??

Seriously, have you tried taking it to a main dealer for proper diagnosis?

[Monty Python]

Ozzie Osmond said:

Seriously, have you tried taking it to a main dealer for proper diagnosis?

At that age I'd be looking for an independent BMW specialist.

Also, I'm struggling to see how resetting the ECU will affect a manual gearbox.

Add - have you checked the throttle position sensor?

Edited by Monty Python on Tuesday 24th May 11:47

Edited by Monty Python on Tuesday 24th May 11:48

[C70R]

Gammelhagger01 said:

I have not yet:
Changed fuelfilter

Seems odd, when this would have been one of my first ports of call (particularly if it's original).

This should take you no more than an hour, but make sure you are on level ground and have some spare fuel hose and clips (to replace the ones that you will inevitably sacrifice.

There's a good guide here: https://www.youtube.com/watch?v=i7Y2Ln6EJks

[Gammelhagger01]

I have had it diagnosed by BMW, and since it throws no codes.... there is nothing wrong :-(

Fuel filter might be a god idea.... but it is only 2-3 years old, so I assumed it was ok...

I have not tested the vanos solinoids yet, since I´ve heard that they don´t fail very often. But I will give them a check up !

[RobM77]

I've not got answers for you, but I do have a lot of sympathy. I owned a year 2000 model E46 330ci back in about 2003/2004 and it had so many gremlins that I eventually gave up and sold it. I had bought it from a BMW main dealer, so they worked hard on sorting the problems whilst I drove around in various courtesy cars. They pretty much gave up after a while, after which I spent money with third party garages (on the advice of PH I think), who also failed, so I just sold the stupid thing after all of that! I returned to BMW ownership with an E36, then a Z4C and now with an E90, and have had much better experiences with those three.

[Gad-Westy]

This sounds like an intermittent problem which is of course the worst kind but have you done some basic TLC around the engine bay? Removed any connections, cleaned contacts both sides and reconnect. Whilst there, check for any suspect wiring, maybe where sleeves are broken or supporting clips have come off. Would suggest you do this right back to the ECU.

[teabelly]

Could be a faulty ECU? I saw a 2002 3 litre that needed some kind of ECU repair after persistent poor running and several expensive break downs happened. Owner sold it not long after so I don't know whether that fixed it or whether they were so fed up they got rid.

[BuzzBravado]

330Ci is common for splitting the intake boot where it meets a case vent. You need to take the airbox out to see it. Its worth checking as its free.

[Mave]

As well as all the replacement stuff, has it had a good general service? What condition are the spark plugs in?

[ADEuk]

BuzzBravado said:

330Ci is common for splitting the intake boot where it meets a case vent. You need to take the airbox out to see it. Its worth checking as its free.

+1 seen loads of split intake boots, a right PIA to change on some though

[C70R]

Gammelhagger01 said:

I have had it diagnosed by BMW, and since it throws no codes.... there is nothing wrong :-(

Fuel filter might be a god idea.... but it is only 2-3 years old, so I assumed it was ok...

I have not tested the vanos solinoids yet, since I´ve heard that they don´t fail very often. But I will give them a check up !

Vanos solenoids failing should throw up an error code, which would probably rule them out.

In your position, I would be starting with the cheap/easy stuff (like the intake boot and fuel filter), and working my way up the cost chain.

[_Neal_]

Have you tried a throttle reset? See here - although I guess disconnecting the battery probably has the same effect.

[Gammelhagger01]

Thank´s for all your comments and suggestions guys.... highly appreciated :-)

The intake boot is fine.... and so is all other hoses and tubes as well as crankcase ventilation etc...

I have owned many other BMW´s and never had so many problems before. By now I think the E46 is a crappy model to be honest...
:-(

I do the re-set almost every day.... if I don´t it becomes almost impossible to shift gears...
I think I will change the fuel filter and if that does not work, I will try to sell the car since I am by now so damned annoyed. It only spooks me that sometimes the car runs perfect, and the next time I start it it runs like crap.... so very strange....

By now I have spent a ton of money on it because in the past I have always been able to make my cars run..... but this time... not so much....

The car has a full service history and when I got it ( october last year ) I gave it a full service with new plugs, oil, gearbox oil, air filter, the works.... I got it cheap I thought..... but now I guess I know why the seller sold it cheap.

[teabelly]

Fuel pump relay is another one to check. That can cause all sorts of running issues.

[sasquartch]

You've changed all the common things - the suggestion to check the intake boots is a good one. I have a 530i but will have a very similar M54 engine

Possibly a blocked cat could cause problems. Difficult to test but by giving them a good tap might reveal something loose inside. Lambda sensors might be playing up. VANOS seals are a common problem on these engines and cause poor low down torque.

I'd be inclined to get INPA set up on a laptop and drive around with an assistant who can monitor the live values and see if you can track the fault down.

I wouldn't just keep on changing things at random (as without fault codes that's what you're really doing)

[Ozzie Osmond]

Get some proper diagnoses. Don't be frightened of the dealer. Pay them to tell you what's wrong. That doesn't mean you have to get them to do an expensive repair, you can sort it out however you like.

Chasing about spending time and money changing bits without knowing what's wrong is IMO not a good way forward.

[BuzzBravado]

Regarding the gear changes.... have you changed the clutch delay valve? There is a mod where you can do away with the valve and its supposed to make gear changes better.