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Discussion Starter #1
Hi guys new to the forum.

So ive had a 2001 330ci for about five years now. Ive done plenty of work on this car myself. For a while my car has had rough idle during stops, in the morning and misfires. when checking CEL codes it give me fuel bank low and random multiple cylinder misfire.

Things ive changed:

170k miles currently

new fuel pump
new fuel filter
new injectors
new MAF sensor
new coil packs
new spark plugs
all new engine seals
new intake hoses
K&N filter

when the car is in cold start, it idles very rough and begins to misfire and then i need to turn the ignition off and start it again. this also happens sometimes when i am driving and the car is warm. when i come to a stop the car begins to idle rough and misfires and again i need to restart the engine. a few times however in really hot weather after changing my MAF sensor, the car while driving would lose power and the EML light would come on. i lose a good amount of power and acceleration and then i need to turn it off and on again (it clears). My question to you guys is what could the cause of this be?

1) I have read a few places where the cause of this can be the adjuster unit? my adjuster unit on the intake manifold seems to be malfunctioning and rattles.

2) some say for the cold start it can be the secondary air pump/smog pump??

3) could it be any o2 sensors?

4) clearing adaptation values with carsoft?

I am running out of diagnosis here and would appreciate some help. I dont know what else to change but my main guess is the adjuster unit or the smog pump which kinda are pricey.

If anyone had similar problems or anyone can help thats be great..

thx!
 

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Have your car's CCV system ever replaced? And if you going to do the CCV you might as well do the VCG and oil filter housing gasket too.
 

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Have you cleaned your Idle control valve?

Here is some info from a BMW document for the MS43 ECU on the M54 3.0 liter: Page 45

http://www.bmwmotorsports.org/BMW_docs/m54x5.pdf

IDLE SPEED CONTROL
The ECM determines idle speed by controlling an idle speed actuator (dual winding rotary
actuator) ZWD 5.
The basic functions of the idle speed control are:
• Control the initial air quantity (at air temperatures <0 C,the EDK is simultaneously opened)
• Variable preset idle based on load and inputs
• Monitor RPM feedback for each preset position
• Lower RPM range intake air flow (even while driving)
• Vacuum limitation
• Smooth out the transition from acceleration to deceleration
Under certain engine operating parameters, the EDK throttle control and the idle speed actuator (ZWD) are operated simultaneously.This includes All idling conditions and the transition from off idle to load.
As the request for load increases, the idle valve will remain open and the EDK will supply any additional air volume required to meet the demand.
Emergency Operation of Idle Speed Actuator:
If a fault is detected with the idle speed actuator, the ECM will initiate failsafe measures depending on the effect of the fault (increased air flow or decreased air flow).
If there is a fault in the idle speed actuator/circuit, the EDK will compensate to maintain idle speed. The EML lamp will be illuminated to inform the driver of a fault.
If the fault causes increased air flow (actuator failed open), VANOS and Knock Control are
deactivated which noticeably reduces engine performance.
 

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Oiled filter?

Disconnect the new maf and see if it runs better.

If it does, clean maf or buy a non-ebay one (don't know what you got)...or buy the hyundai maf that might be the same as yours...return to either stock air box or just plain old, crappy piece of filter the bmw engineered coz they weren't as smart as the KnN folks...sorry! LOL

If you do anything with icv, you have to think, at least, about doing some more..all inexpensive, but all might add up together for a little improvement...too tired to tell you more than to search for me and keywords, icv, maf, disa, tb, gasket, o-ring, grommet, heating hoses, rtv

HTH

PM me if you can't find about my trip to TB.

Doug
 

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Discussion Starter #6
yes ive changed the CCV system. thx for the posts guys ill keep yall updated as soon as i figure this out. thx a lot
 

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VM330ci I have the same problem that your having right now.

I need a fix to this problems. I am tired of stopping on a sidewalk when I get a misfire and turn the car off and on just to reset it.

I'm tired of my bmw. Too many problems.. Never stops..:facepalm:
 

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misfire/rattle problem is most likely caused by one of the parts of intake system..Clean up ICV/throttle body.
And it's not totally related, but resetting throttle body(only for drive-by-wire cars, M54 engines) could help you to solve the problem.

1) I have read a few places where the cause of this can be the adjuster unit? my adjuster unit on the intake manifold seems to be malfunctioning and rattles.
Well DISA valve should not be rattling..You should replace it soon.
But as far as I know, DISA only works when the engine wants to inhale big amount of air(when you push gas pedal to the end), so it's less likely the reason of misfire/rough idle.

2) some say for the cold start it can be the secondary air pump/smog pump??
2ndary air pump works only in cold start, so yeah if your car makes misfire too many times in cold start, clean up your 2ndary air pump.

3) could it be any o2 sensors?
Less likely.

4) clearing adaptation values with carsoft?
umm...not sure what that is.
 

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damn i'm having this exact issue right now, I'm curious to know if you were able to find the problem. what i've done so far is: New Fuel Pump, New fuel filter, New DISA, New Coils, sparks are fine, Just changed the vanos seals, and valve cover Gasket, cleaned up the throttle body, i've done Motorvac and a new Gas Tank Cap cause it was loose!! I'm having idle and misfire issues while standing, driving, parking, reversing... Disconnected the battery and it resets everything and drives like a beast and 2 hours later back to where it was!!! its annoying as hell!
 
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