Engine Hesitates

M

mexicruiser

New member
Hi just joined the forum, really happy it exists and I found out about it, any help appreciated:

Just got a 2006 Z4 M with several issues but the one that is most important to me now is: the engine stumbles/hesitates when accelerating from idle, this makes for an uncomfortable take off as you have to pre-accelerate a bit more before releasing the clutch in order to avoid stalling; I also noticed with the engine idling the electric motor that drives the throttle shaft is rattling the linkage, it does not actually affect the idle quality much but you can hear the shaft linkage moving erraticaly.
Any body heard of this or had any similar simptoms?
Thanks
Jon
 
i have developed a misfire/hesitance on my 2.5, apparently there is a common problem with something called the vanos seals which can cause hesitance in acceleration in the lower revs, its something im checking out myself at the moment, apparently the rubber used for the seals cannot deal with the heat and perrishes, i know theres a guy on ebay selling twin vanos kits with viton seals for about 40 quid, might be worth a look, sorry i cant be much more help, but if you google vanos problems there will be loads of info come up.

Mine only misfires underload, so my issue might not be the vanos it could be coil packs, but by the sounds of it the vanos seal upgrade would be worth doing anyway.
 
Hi and welcome

Sounds like some sort of sensor problem, common fault

Have the codes read with an OBDII reader or take it to BMW
 
Exact same problem as mine, 2006 Z4MR, 22K miles.
Was back at the dealers today for 2nd time with hesitation problems, mechanic drove it with me in the car and it misfired a couple of times at low revs.
He thinks it may be slack in the dual flywheel set-up, contacting BMW UK to see what they think. Mechanic has replaced a couple of flywheels before.

No fault codes are thrown up by this as its mechanical, O2 sensor was replaced the last time I was in which seemed to help but not eradicate the problem.
 
mad_mackem said:
i have developed a misfire/hesitance on my 2.5, apparently there is a common problem with something called the vanos seals which can cause hesitance in acceleration in the lower revs, its something im checking out myself at the moment, apparently the rubber used for the seals cannot deal with the heat and perrishes, i know theres a guy on ebay selling twin vanos kits with viton seals for about 40 quid, might be worth a look, sorry i cant be much more help, but if you google vanos problems there will be loads of info come up.

Mine only misfires underload, so my issue might not be the vanos it could be coil packs, but by the sounds of it the vanos seal upgrade would be worth doing anyway.
Click to expand...

This is the tread about the Vanos repair... http://www.z4-forum.com/forum/viewtopic.php?f=2&t=3600
 
Jon - welcome to the forum. Nothing to add from what has been said. Search this Forum and you will find all the answers I'm sure. :thumbsup:
 
Hello and thank you everybody for your welcome and advice, I promise to re-check this forum for info; however I feel I should have added: The car was at the dealership and there where (at the time) no fault codes stored on the DME, tech also said no related service bulletins; no misfiring or engine malfunction other than off-idle.
I suspect the throttle shaft rattling has something to do with it, its just not normal for the accelerator drive to move the throttles erratically at idle and on its own.
I was an BMW auto tech for a couple of years but was promoted to Manager in 1999, I used to do work on M3 engines but with cable operated butterflies (no babysitter DSC or ASC+T), now I don't get to work much on customer cars anymore as I have my own shop.
Hey! Even went to Germany in 1997 for the international BMW technicians contest representing Mexico, GB won as I recall, those guys did a great job. We didn't stand a chance as we had two years experience (BMW de México started in 1995) and much of the contest was on older cars, had a great time though...
 
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