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What about the filter?
 

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Discussion Starter #23
Update

Ok since the my last post I came to the conclusion that my problem was through incorrect air intake so was told to unplug the maf and run the car like that. After doing this the car ran great, obviously still not perfect but loads better, so went out and bought a new maf, after installing and plugging it back in my original problem is back! Car is sluggish, misfires and sounds ****e. What else could this be if it runs well without the maf plugged in??
 

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I had the same thing, was my knock sensor.

All would be good for a little while if i turned her on and off again, but it would always come back real quick.

In my case it was the harmonic balancer setting off the knock sensor.
 

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Ok thanks wolfie, never heard of it but will look into it! :)
I tried everything before I found out. Spent $$$$$ Thousands $$$$$ and my new #1 mechanic spotted it almost right away and fixed it all up for about $500 (Most of that was the second hand harmonic balancer)

No promises, but the running issues are the exact same as mine were.
 

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Ok since the my last post I came to the conclusion that my problem was through incorrect air intake so was told to unplug the maf and run the car like that. After doing this the car ran great, obviously still not perfect but loads better, so went out and bought a new maf, after installing and plugging it back in my original problem is back! Car is sluggish, misfires and sounds ****e. What else could this be if it runs well without the maf plugged in??
When you start the car, the engine runs on a basic fuel/air map/programme, and is not using the MAF and certain other sensors. After the first 20 secs or so, it switches to real-time monitoring/adjusting based on sensor inputs. So the engine is getting conflicting info - the MAF is saying X amount of air is coming in, but something is causing it to run poorly based on that input. Either an air leak, fuel pressure issue, or maybe your pre-cat o2 sensors are giving out. If they have near 160k kms or more, they should be replaced. They give the readings to the computer after combustion to tell if anything's off in the mix. If they don't perform well, you can get sketchy feedback and improper real-time engine mix adjustment.

A knock sensor will retard timing and alter the mix when it detects a knock b/c an engine is running very poorly when it knocks. It's probably called a ping sensor. I'm doubtful this is your issue. Our Aussie friend had a bad harmonic balancer (main belt pulley on the crank) that simulated rough running/knocking.

http://www.realoem.com/bmw/showparts.do?model=BN32&mospid=47617&btnr=12_1079&hg=12&fg=05
 

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Maybe call it a ping sensor? Knock Ping is the listing, but we always call them knock...
Bingo! But still probably a long shot that it's the problem here. Not common for the HB to go bad and trip the sensor.
 

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Bingo! But still probably a long shot that it's the problem here. Not common for the HB to go bad and trip the sensor.
Oh yeah, typical for me to get the 1 : 1,000,000 problem and spend a fortune finding it.

But I only mention it as an option, certainly wouldn't go out and change it until it's proven!
 

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Oh yeah, typical for me to get the 1 : 1,000,000 problem and spend a fortune finding it.

But I only mention it as an option, certainly wouldn't go out and change it until it's proven!
Options are good to have. What kind if codes did you have? EDIT: found the thread. Interesting there's no code for the knock/ping.
 

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Options are good to have. What kind if codes did you have? EDIT: found the thread. Interesting there's no code for the knock/ping.
No CEL either. Was a really odd problem! Got to the bottom of it in the end by noticing that the HB had a half inch run out on it, noticeable on closer inspection. As you see it was full of cylinder misfire codes, and my suspicion was fuel cut off on those cylinders also after doing the coil pull test.

Just glad it's all over now! :thumbup:
 

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You're headed the right way, most likely a vacuum leak. If you don't find any on the elbows, verify that the dummy plug behind the manifold was installed after the replacement motor. The DISA can leak too if the diaphragm is torn, so check for that too while you have it out.

Courtesy of another member:

<a href="http://www.flickr.com/photos/[email protected]/9952974046/" title="intakemanifoldvacuumrea by cvx5832, on Flickr"><img src="http://farm3.staticflickr.com/2847/9952974046_61aba98630_o.jpg" width="640" height="480" alt="intakemanifoldvacuumrea"></a>
thanks for the picture. I made replacing my electric vacuum control valve much easier
 
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