Help needed! Car jerks @ ~3000 rpm!

Hey all!

Not too long ago I began noticing that my '03 325i would start jerking (or hesitating) at around 3000 RPM when accelerating. This especially happens when accelerating hard. I haven't taken it to any mechanic yet, wanted to get some feed back first!

Thank you for your help!

Wow, my car does this too. It's only noticeable in 4th gear and it happens around 3000 RPM like you said. I started noticing this after swapping in a 3.91 diff. I don't know what is causing it.

The car doesn't really jerk forward, but the RPM's dip about 50-100 when it hits 3000 and then the RPM's start building their way up normally as if it never happened.

http://www.bimmerfest.com/forums/sho...19#post3719519

That seems like it applies to ZHP's mainly. The post about fuel filter seems interesting though...gonna think about it.

Here is the old thread I made...never found a solution:

http://forum.e46fanatics.com/showthread.php?t=608152

Most likely a dirty MAF. Other possibilities are the vanos, oxygen sensors, plugs, and coils. It's unlikely to be the fuel filter as it would affect the entire rev range.

For me, it's really noticeable in 3rd gear! Sometimes it seems like the car is struggling or hesitating to accelerate for those two secs, but once the RPMs jump above 3K everything is fine! I propose that we find a solution so that everyone benefits from it!

Yeah..I feel like it is something with the ignition system. I'm not 100% sure what it is though. It feels totally fine everywhere else. It's only at 3k RPM in 4th gear. I'm guessing it might be at 3K for you since you have a taller ratio. It feels like the engine is being bogged down for a split second.

could be you need a new fuel filter.

i'm telling you the thread post that i was in and posted above was exactly what i was experiencing and solved.

i had SES thrown with o2 sensors being thrown.....

but....the dealer did a ECU parameter update which fixed the O2 sensing issue. they suggested that it might not be the only problem and that i should pay out the ass to change the two O2's. i opted out...and to run the car to see what happens and if i had to i would DIY that.

there was never another hesitation as you state and still there is not 8K miles later with spirited driving. just an FYI / just an idea to consider

I have the same issue with my 04 zhp, but with no codes or CEL. I've had a new fuel filter, air filter, replaced the vanos seals, and had the DME updated in May of 2008, none of which has fixed it. This doesn't seem to be too isolated, I posted on the bmw cca forum and found several people having the same issue, mostly zhp cars. I'm wondering if there was a newer software update between when I had mine done in May and when you got yours done (throttlehead) in November.

Wolfe

A new update from stated date to date i am not aware of. I do know that they stated that they did not do a DME update, that they did not update the know 4K RPM hesitation that has been recorded/identified.....and I know that they didn't tell me exactly what they did...bu that it was software related with a 1.5hr charge !!!

When i did my research on ZHP 3K rpm hesitation.....it appeared that BMW software writers may have given a fairly narrow parameter of low and high readings for compliance with the O2 sensors. (intentional?) but if you are knowledgable, and in my case the dealers are apparently aware of this and the software parameter widening fix so you don't have to be stabbed with O2 replacements when not really needed.

It was interesting how much the service manager attempted to have me not just accept the software tweak but to pony up for O2 change outs to "make sure"......and i was like I'll see how this works out first.....

Ive had a similar issue arrise with my 00' 323i.
find your MAF and follow it down to the side of the motor. It should wye off with a smaller tube about 1'' in size. Feel with your pointer finger around the 1" tube in the 3-4 o clock position. It is common on for the intake tube to crack in that area, when it does it lets air into the engine undetected by the MAF, which in turn will make your car run like crap, bog down, and the worse it gets your check engine light will come on and throw codes like 1188 and 1189. hope this helps.

Thanks for the help everyone.

One thing to note is that this has never triggered any lights in the cluster for me.

throttlehead, were you experiencing the hesitation in every gear or just one? Mine ONLY happens around 60 mph in 4th gear turning 3000 RPM. My car isn't a ZHP either.

my juttering hesitation only happened right at 3k rpm and moments afters continued as nothing had occurred into the rev range.

this i guess could possibly occur in any gear...but i paid attention to how i drive and accelerate....that being that 3k hesi was only only noticed in 2nd or 3rd / 6mt

Originally Posted by throttlehead

my juttering hesitation only happened right at 3k rpm and moments afters continued as nothing had occurred into the rev range.

this i guess could possibly occur in any gear...but i paid attention to how i drive and accelerate....that being that 3k hesi was only only noticed in 2nd or 3rd / 6mt

SAME HERE!

Thank you to all that have contributed

Also, throttlehead, how much was the software upgrade? Or do they do it for FREEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE?

Originally Posted by B3ZKONTROLU

Also, throttlehead, how much was the software upgrade? Or do they do it for FREEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE?

not CPO'd

so you pay for diagnostic and time i believe it was an hour totalling $250 for a little download.....

but it did rectify perfectily with no further issues! there is work sheet posted somewhere about it......

that i shared to let them know that i was fully aware of what needed to take place.

Originally Posted by throttlehead

my juttering hesitation only happened right at 3k rpm and moments afters continued as nothing had occurred into the rev range.

this i guess could possibly occur in any gear...but i paid attention to how i drive and accelerate....that being that 3k hesi was only only noticed in 2nd or 3rd / 6mt

My 2004 ZHP started doing the same thing about a month or 2 ago. My friend/mechanic owns his independent shop and drove it the other day, he felt the dips around 3k range in 3rd and 4th gear. He suggested a possible tune up with plugs changes and stuff...

My 60k inspection is not due for another 7500 miles so i wasn't sure if I should take it to the stealer before hand or get my inspection 2 done early...

Glad I stumbled on your post! I'm going to schedule an appointment for this weekend and see if I can get that software update downloaded to my DME.

I guess we have to pay the steep labor price for the time for the techs to do it, but if they charge for the for the download itself it wouldn't be fair since the software was buggy to begin with.