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Throttle hesitation

Discussion in 'E46 (1999-2006)' started by cla67, Jun 10, 2009.

    bobbythecard guest

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    Isn't it a drop of 400 and not 4k? Only because you would have to be revving pretty high in the gear to drop 4k.

    Enhanced 3 guest

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    It isnt a 4K drop in RPM. It is a slight blip in power that you get when accelerating and you hit 4K rpm. Almost like you loose power for a second before the car catches it self. In my case, the problem that was causing this blip, also cause the car to idle rough and stall out.

    bobbythecard guest

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    I finally gave in because I read codes; Table 20: 28DD- Air mass system, 2974-O2 sensor befor cat, bank 2 and another code for camshaft sensor and brought the car into Vicari Motors in Frenchtown, NJ. They repair only BMWs.

    I uploaded the diagnostics from their computer (see attched pdf). Basically, the coolant tempature read zero during the mass air flow system test but should have read 99 degrees.The car was never updated aince I bought the car (2003) for the newer software.Since the DME was not reading sensors correctly they deleted the old memory and put in the updated software (73 minutes to update).In the end there was not anything mechanically wrong as no parts were replaced.

    I drove the car home and this morning and no hesitation.

    You would think that BMW dealers would do the update when I brought the car in for the BMW scheduled maintenance (while under warranty). God forbid they should do their job or is it a scheme to get you back in for the $$$$$$$$$$$$$?

    I hope this helps.Please let me know if you got the attached pdf, otherwise, I will upload again.
    • Member

    cla67

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    I apologize for not replying sooner, since I started this thread.

    More info on the issue:
    Check engine light would come on intermittently.
    Would hunt for idle and sometimes die while at a stop.

    However, this was only during hot, humid weather. Since it has cooled off (lower 70's) I have not noticed any significant problems. Of course I don't drive it every day, but I haven't heard too much bitching about it lately.

    I'm trying to talk her into taking it in before the service date. She wants to wait for the scheduled service interval.

    Thanks to everyone for posting their info.

    Chris

    mose121 guest

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    It doesn't work that way. Goes back to the old saying "if it's not broke don't fix it". Not all cars will have the same symptoms even with the same level of DME software. Thus, the software is updated on a client complaint basis only. Just because it's newer doesn't mean it's better for every car. Sometimes you can actually create a problem by updating the software. Sounds crazy I know but it happens. Every manufacturer works like this in regards to software. Almost every bulletin starts with "on a client complaint basis only..."

    bobbythecard guest

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    Customer complaint basis is an excuse in the auto industry, especially with BMW which almost always in the bottom 50% in customer service. It has nothing to do with "if it isn't broke don't fix it". It has to do with I build a car with some faults and hope the customer does not catch what they did wrong.

    The car companies know that they can get away with murder and that any car will be able to survive the warranty period and then things start to break after the warranty has expired.

    I owned a 1984 325e for 17 years and the paint and engine etc were better than the current 330ci...and the parts and labor were cheaper and easier for DIYers.

    Agreed that software can cause problems but they are "The Ultimate Driving Machine".
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    aaronb9

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    Bobby, I wasn't able to see the link to the PDF. Would you mind uploading it again please?

    I replaced the spark plugs on my car this weekend, #1 had a bit more carbon on it than the rest, and 2 through 5 had a little oil on the threads (I suspect the valve cover gasket was the culprit, I replaced this when I did the vanos seals and it had become hard with age). The electrodes looked in pretty good shape, I compared to several spark plug condition charts online and they looked fine/normal.

    Didn't make a bit of difference to how the car drives though. I do feel a little airflow around the intake boot elbow when the engine is running, but manipulating the boot doesn't seem to affect the idle at all.

    I'm hoping there is a more recent software update than the one my car recieved.

    bobbythecard guest

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    The file is too big to upload. Send me an email with your email address to mmurphy114@comcast.net. Anybody else can also email me.
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    aaronb9

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    I'm planning to replace the oil separator + hoses, disa valve, and air intake boots this weekend if I get time. I'll update on whether or not it made any difference.

    bobbythecard guest

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    I am just curious about the oil separator and thought process (i.e. why?) for the replacement?

    The DISA valve is a flap that will rattle when bad and also a lot of the things I read about it require the computer to be reprogrammed after replacement.
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    aaronb9

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    I'm doing the ccv more as a preventative measure and to rule it out. I know the hoses are brittle and I figured I'll have all the intake stuff out the way to replace anyway.

    I've also seen about the reprogram/adaptation reset after replacing the DISA valve, I've been in touch with a couple of dealerships to try and find out what the newest version of the ECU firmware is, but so far nobody seems to know what I'm talking about. I'll be interested to see the condition of the DISA valve that's in the car now. The new one has no slop in it whatsoever.
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    aaronb9

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    I've now replaced the CCV and all associated hoses, replaced the throttle body gasket, the ICV gasket, both pieces of intake air boot & the connecting piece, and the DISA valve.

    I noted the old CCV hoses were definitely brittle, and the intake air boots were in surprisingly good shape (no visible rips, tears, or holes).

    The DISA valve I fitted appeared to be a newer design, at least the integrated sealing ring did anyway.

    I think this has helped the 3k stumble a bit, it's still there from time to time but I would say it's considerably less severe. My guess would be it was the DISA valve moreso than the CCV.
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    aaronb9

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    I have now had the DME reprogram performed. This was the final piece, and the one with the most noticeable results. The car is still weaker on power below 3k, but it's now very smooth throughout the whole rev range. No stumbling, no hesitation. the power dip at 4k through 5k is now imperceptable. I would feel when the engine hit 4k without even looking at the rev counter, now I can't tell. It doesn't feel more powerful, but the power delivery is no longer lumpy.

    The DME reprogram (SIB 12 17 05) and the updated DISA valve seemed to be the two things that made the most difference. All the other items I replaced appear to have been unnecessary in my car's case.

    I know I appear to be replying to my own post, but hopefully this update will help someone else get this resolved without throwing too many parts at it.

    bobbythecard guest

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    So glad the reprogramming helped. I think a chip would help the acceleration below 3 grand. I am now conquering my wife's E39 problem with her blower resistor. First problem was blower only went so high. I put a new one in and it solved the problem for a week. Then she came home and the blower stayed on after the car shut off.... disconnected the battery.

    I called Bavarian Autosport for overnight replacement and we are one week into success. By the way I compared the values of the pins (new vs old) and the values were different for #2 to #-3 pin measurement. To replace this same resistor on an E46 is a lot of work that includes taking out a servo motor....just for future reference.

    aurelius guest

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    2800-3k RPM hesitation M54 motors: solutions

    This problem is known as "VANOS stutter." Some have had luck replacing the vanos unit and others report solving the issue with DME updating and/or updated DISA valve part number 11617544805.

    Do NOT buy BMW's rebuilt vanos unit - they are done with the exact same failure-prone seals that cause the problem in the first place. Not to mention it's $500. Instead, see DrVanos.com and all will be explained. $250 for the dual vanos, no special tools required. Save your old one for core charge refund.

    The 4k rpm power dip is a different issue and is addressed via DME software update.

    You may also want to check if your car ever had the ignition coil packs replaced as per recall. Not all models qualify, your car must be within affected VIN range. More on that & vanos issues in the following thread:

    http://www.bimmerfest.com/forums/showthread.php?t=120971

    Note: DME updating, either at a BMW dealer or at an indie shop using autologic, will overwrite any performance software you may have. But performance software will not overwrite the relevant parts of the BMW software update. Therefore, update first.

    Note 2: DME updates once required sending the DME to BMW in New Jersey. This is not the case nowadays.
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    az3579

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    The seals can be replaced/upgraded with a kit from Beisan Systems. Cost was around $30 for me (Single VANOS) if I remember correctly. Should be $60 for Dual-VANOS.
    http://www.beisansystems.com/

    If your VANOS unit is still functioning, get this kit as soon as possible. No new VANOS unit needed.

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