Z4M initial drop in revs?

[ghahat]

hi everyone,

bought an 06 Z4M recently, noticed an issue:

when i hit the gas and the car is idling (below 1000rpm) the rpms initially drop, sometimes to almost 400rpm, then it goes up.

if i hit the gas when above 1000rpm, it revs up without the dip. although, i feel while im driving that there is a slight delay between my hitting the gas and the revs coming up. (could be just me comparing to my previous car which was a s2000)

no vibrations or anything when the dip happens. the car never feels down on power, pulls hard and smooth all the time. only 10K miles on it.

took the car to the dealer (still under warranty). they cleaned the intake manifold and reprogrammed the ECU, but this is still occuring. they told me its normal.

is this normal? do any of you experience something like this?

[Caddyshk]

Normal for mine when it has sat more than a day.

[RBull]

Same here. Worse when temperatures are lower.

[Z4-VILLA]

i just moved to nyc so im wondering when this will happen to me. would worry too much though

[JB 007]

I have the same issue..Bmw dealer said it's normal but It's don't normal...

[Z4-VILLA]

overall bmw service is shady as fuck period. they dont know want to pony up the fucken service.

[ghahat]

thanks for the replies guys

hehe, ditto on the bmw service. the handbrake lever was faulty when i bought it, they changed it and the mechanism under warranty, but they charged me $35USD to check the handbrake issue!!

i always thought if its under warranty, a dealer should do everything for free and apologize for the inconvenience, no?

anyway its refreshing to hear that its common.

[johanness]

I don't think it should be okay because it's common. A delay in throttle response and a dip in RPM doesn't sound like that's the way it's supposed to be. For the record, I don't have this issue. Either when it's cold or hasn't been driven for days. Wondering if this has been brought to BMW's attention? (aside from a few desk-jockeys at the dealership saying that's the way it's supposed to be)

[ghahat]

yes i complained about it.... they cleaned the manifold and reprogrammed the ecu. i even spoke to the service manager.

i am in qatar though, and everything here is through their local dealer for the country. is this a way to inform bmw directly? my car is still under warranty.

[ghahat]

i read this on another forum

http://www.bimmerfest.com/forums/sho...d.php?t=487805

could it be the spark plugs and coil packs corroding? seems bmw has changed the supplier 3-4 times...

i will take a look at mine and post a pic. perhaps you guys who have this problem could do the same?

johanness, since you dont have this problem (or anyone else who would like to help), would you mind posting a pic of yours (should you ever happen to be changing your plugs anyway )

[Z4-VILLA]

i have heard of a set of plugs called Okada dont know what the word is on that though but I would say ignition could be to blame and maybe even vanos could be improved.

[just2talented]

Originally Posted by Z4-Villalona

i have heard of a set of plugs called Okada dont know what the word is on that though but I would say ignition could be to blame and maybe even vanos could be improved.

Ditto. I have an 06 with 25k on the clock. Never noticed it at startup. However having said that i notice that if i dont drive it for a day or two then drive it only a few miles and park it, the revs would drop slightly and then pick back up to normal. This was very rare and sporadic so i never complained. Your revs at start up should shoot up to about 1500 or so then drop and stay at a very steady 900 rpms. If thats not happening you need to bring it to your dealer and complain. Theyve reflashed your ecu which means they noticed the problem and either cant diagnose it properly ( very likely) or its something serious and they dont want to be bothered.

[pokeybritches]

My car's cold start behavior improved dramatically after I got my AA tune. This can either be attributed to resetting the ECU or having the AA reflash, but either way it seems to be something software can fix.

[ghahat]

problem solved,

airflow meter was replaced, made a big difference,

then the idle regulation valve

also a reset of the ecu

[BlackMoupe]

I have the same problem. Always happens after a long red light or when I'm waiting somewhere idling...will have dealer check it out.