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7 Series - E38 (1995 - 2001)

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  #1  
Old 04-16-2012, 02:46 PM
Danny Wolfe Danny Wolfe is offline
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Exclamation Advice??? What may be wrong ??

I have a 2001 740i sports package car. I just have replaces both vanos units, timing chain and guides, tensioners, and replaced plugs about 7500 miles ago. BEFORE i had that dreaded noise from the Vanos, clattering timing chains. All that is corrected and sounds very quiet, however, i have a ROUGH IDLE. This was not present before changing the chains and Vanos units. There is NO SES light, and car runs fine once you are moving. Sitting at a light it feels like it is misfiring, but again NO SES light. When i turn the AC compressor on the idle slightly raises and seems to run smoother.....i have noticed that i have a vibration up to about 2000 rpm but most noticeable at about 1500, which i did have before having all this work done. Please advice and give me your thoughts.....and as USUAL, I DO APPRECIATE ANY OF YOUR THOUGHTS AND HELP!!!!
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  #2  
Old 04-16-2012, 03:37 PM
setconstr setconstr is online now
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Mein Auto: 2001 740i sport 2006 m6
re

I had a rough idle and it turned out to be the MAF
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  #3  
Old 04-18-2012, 11:27 AM
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joyism5 joyism5 is offline
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Quote:
Originally Posted by Danny Wolfe View Post
I have a 2001 740i sports package car. I just have replaces both vanos units, timing chain and guides, tensioners, and replaced plugs about 7500 miles ago. BEFORE i had that dreaded noise from the Vanos, clattering timing chains. All that is corrected and sounds very quiet, however, i have a ROUGH IDLE. This was not present before changing the chains and Vanos units. There is NO SES light, and car runs fine once you are moving. Sitting at a light it feels like it is misfiring, but again NO SES light. When i turn the AC compressor on the idle slightly raises and seems to run smoother.....i have noticed that i have a vibration up to about 2000 rpm but most noticeable at about 1500, which i did have before having all this work done. Please advice and give me your thoughts.....and as USUAL, I DO APPRECIATE ANY OF YOUR THOUGHTS AND HELP!!!!
I am experiencing the same thing. Slight vibration on the engine after I replace the VANOS seals, timing chains & guides. Engine runs excellent, but is just that vibration. My thoughts are that there is a timing issue. The timing might be off just by couple degrees. In my case I am pretty sure that I need to adjust timing, because I did not use any special tool for the top end overhaul. Now I am trying to set up the INPA software to read the car DME for BMW codes.

What you can do : Take your car to a BMW dealership to have it scanned with BMW software or to the guy that fixed your VANOS/timing and tell him to scan your car for BMW codes. You might have some codes stored in the DME while the SES light is OFF, because they might be codes that are not considered to be Emission related.
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Old 04-19-2012, 07:15 AM
Danny Wolfe Danny Wolfe is offline
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Thanks for your input! I have also noticed that AT IDLE that the vibration or misfire is just a bit less when i engage the AC Compressor. or is just not as noticable when the rpms are just a little higher. It is also very noticeable when the car is in "Park" at 1500 rpms. However, i have noticed that this vibration is sometimes worse when the weather is cooler, and that the idle may move a bit. You can feel the vib sitting at a traffic light also a bit worse. I have also noticed that the Gas Mileage in city sometimes drops down to around 13-15 as it used to be around 17 or even at times close to 18 mpg. Do you think this could be an issue with the idle control valve, or the MAF? The MAF was replaced about three years ago. ALSO, during the time before i replaced the vanos units, i replaced spark plugs, but when i first got the vanos replaced, the timing was not correct and i was getting a SES light and flashed at times, indicating a MISFIRE. Could this have ruined a spark plug? Thanks again for your response!!!
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Old 04-20-2012, 08:36 AM
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This is not a MAF issue. I have a brand new MAF and the car still acts the same. I don't have a misfire, or terrible vibration. It does feel when the car is idling, or in D but waiting at the stop light. This feels like a slight timing issue. Not worse enough to cause a misfire, but still not good enough to let the engine run like it should. Get the car scanned by a professional BMW technician and he should confirm that, or tell you if anything else is wrong. It might take a while until I will have my car scanned and I can't tell at this moment if the timing is retarded or too advanced.
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Old 04-20-2012, 08:54 AM
Danny Wolfe Danny Wolfe is offline
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Thanks Joyism5.....is this the cause of the bad fuel mileage as well? AND does this mean that he will have to go back into the timing covers and remove the chains to set the timing? Please explain the process, THANK YOU!

Last edited by Danny Wolfe; 04-20-2012 at 08:56 AM.
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Old 04-22-2012, 06:38 PM
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IF it turns out to be the timing, yes the valve covers + the upper front covers have to come down again, special tools again on the cams, etc. This is only IF. That's why I still drive the car the way it is now until I get some time to mess with it. Since you paid somebody to do all the work, you should not be charged again. They should be able to do it right from the first try. It's a lot of work to re do it and I don't think the person who did it will be happy to hear about it.
First of all, don't loose hope or don't get them angry, scan the car with a BMW software at the dealership or at another shop for second opinion. Make sure the timing is your issue. That only a real BMW tech will confirm it.
And yes, incorrect timing could be an issue for bad gas millage.
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Old 04-23-2012, 12:33 PM
Danny Wolfe Danny Wolfe is offline
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I have noticed that the idle is at about 600 rpm. When i turn the AC on, the rmp rises to about 700 and sometimes it is smoother....could this be that the idle is too low and therefore causing the engine to feel rough? There are times when the rough idle is not apparent at all, but not often. THOUGHTS? I will definitely have it scanned as you suggested and will know more then....but i do wonder if the idle can be adjusted. What is the absolute correct idle rpm???? Thanks again for your advice and input. I hope you have success with yours.....thanks again Joyism5.
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Old 04-23-2012, 10:06 PM
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joyism5 joyism5 is offline
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Originally Posted by Danny Wolfe View Post
I have noticed that the idle is at about 600 rpm. When i turn the AC on, the rmp rises to about 700 and sometimes it is smoother....could this be that the idle is too low and therefore causing the engine to feel rough? There are times when the rough idle is not apparent at all, but not often. THOUGHTS? I will definitely have it scanned as you suggested and will know more then....but i do wonder if the idle can be adjusted. What is the absolute correct idle rpm???? Thanks again for your advice and input. I hope you have success with yours.....thanks again Joyism5.
The RPM can be rised by a certified tech using the bmw software. He has to acces the DME settings. I saw a couple guys did that on the 5 series section (for the M62 engine). If the rough idle is not always, I doubt that the timing is the issue, since that would be a constant problem. It is OK for the engine to get a higher idle with AC on, that is preset by DME. The correct idle should be around 570 in neutral and around 550 in D with AC off. AC ON should raise rpm to 600 at the most. If yours has 700....there is something going on.My opinion. Get it scanned.
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Last edited by joyism5; 04-23-2012 at 10:08 PM.
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