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 ??

[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 !

[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.

[Gammelhagger01]

Ozzie Osmond said:

^^ PH motoring myth number 27.

The MAF is original....

[Gammelhagger01]

_Neal_ said:

Definitely another vote for getting a proper diagnostic done - that could either be main dealer or good independent. Whereabouts in the country are you, sure someone on here can recommend a garage?

Well I´m from Denmark, so I don´t know if any of you knows a good garage here :-)

[Gammelhagger01]

ADEuk said:

I still think the boot needs checking. It won't take much of a split. A big one will give idle problems and trigger the EML, but a small one will just give drivability issues. If it's pulling air in it will confuse the ECU as it won't all pass through the MAF. You could try disconnecting the MAF and see if things improve.

Boot is fine.... no holes. MAF disconnected.... no improvements... :-(

[Gammelhagger01]

Output Flange said:

Don't take it to a main dealer - if it isn't throwing a code, they won't be able to fix it.

Do take it to a decent indie though. I'm sure we could recommend somewhere if you tell us where you are.

I´m in Denmark :-)

[Gammelhagger01]

Rsdop said:

The fact that sometimes it's running fine and sometimes it's not would make me think it's an electrical issue rather than a mechanical one. I've just done a load of work on my 330ci, including vanos seals, intake boot, CCV, Disa valve etc.
The car is now running better in that I'm getting more mpg and definitely a bit punchier, but it didn't feel particularly bad before the work and was showing no fault codes. Only when I did the work I discovered the intake boot had big holes in it, the CCV was completely blocked and so for the symptoms you describe I would think it's a different problem.
Is the new MAF that you mention a genuine one?

I agree.... the Grimlin must be electrical..... but when it does´nt throw any codes ????

[Gammelhagger01]

nitrodave said:

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

have you tested your vanos solenoid?

Fluids are new......

[Gammelhagger01]

Ozzie Osmond said:

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

Yes..... BMW diagnosis finds no faults !!!???

[Gammelhagger01]

Monty Python said:

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

If the problem is of an electrical nature, resetting the ECU will clear the stored faults and the car will run default for a while. A problem with the TPS for an example, will effect shifting... also in a manual..... but TPS is a part of the throttle body which was changed to a new original last week..... helped, but did´nt solve the problem.

[Gammelhagger01]

BuzzBravado said:

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.

No.... was´nt aware it had a delay valve... :-)

[Gammelhagger01]

padhinbed said:

I had similar 2003 E46 330ci. Couldn't find anything wrong and it kept losing power randomly when warm. I had only just purchased the car but privately so no come back.

The previous owner had fitted a fancy air filter thing (don't know make/model). Anyway, I didn't need/want nor see benefit from it so removed it and fitted a normal airbox with a new air filter. Problem disappeared! It was the air filter sucking in warm engine air impacting performance (or aleast I think anyway but the issue definitely went away).

I would check the air filter itself, the boot as mentioned by others and generally the pipework surrounding the air intake system. It's free and easy to check and will help eliminate it from investigations.

Do feedback how you get on.

Mine is an original air filter, and all the hoses are ok... ???

[Gammelhagger01]

Blue Oval84 said:

OP - to repeat what someone asked earlier, have you tried the Throttle Position Sensor?

You can test it yourself if you have a Bluetooth dongle to connect to the OBDII port.

Just fitted a new trottle body which include TPS..... better but not solved :-(

[Gammelhagger01]

Rsdop said:

The fact that sometimes it's running fine and sometimes it's not would make me think it's an electrical issue rather than a mechanical one. I've just done a load of work on my 330ci, including vanos seals, intake boot, CCV, Disa valve etc.
The car is now running better in that I'm getting more mpg and definitely a bit punchier, but it didn't feel particularly bad before the work and was showing no fault codes. Only when I did the work I discovered the intake boot had big holes in it, the CCV was completely blocked and so for the symptoms you describe I would think it's a different problem.
Is the new MAF that you mention a genuine one?

Yes..... the MAF and all the sensors changed are all org. BMW parts.