# ZHP 04' Acceleration Hesitation 4000rpm



## mtarchal (Aug 21, 2004)

Ok, I am really confused so I am starting a new thread. At 4000 rpm, I feel a hesitation when accelerating at a moderate amount. It is pretty close to the 4000rpm mark and it does not happen all the time, but it does. The car sputters/surges like 3 times when going past the 4000rpm mark.

Anyone else have this ? I am confident that there are others out there from reading.

Has anyone called BMWNA and filed a complaint ? I am going to do this and would like to know who would like to join me on this. The car should not do this, it is meant to be driven and reved and that is that. I spent too much money on it for this, otherwise the car is solid.

I assume that the DME stuff is about de-accelerating to a stop. I have a different issue, but seems like people have also been talking about it. 


2004 zhp, Manufactured date April 1 2004


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## KrisL (Dec 22, 2001)

Please search the 3-series board for "4000 rpm" and you'll find many results.


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## RSPDiver (Jul 14, 2004)

http://www.bimmerfest.com/forums/showthread.php?t=69648


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## dynosor (Jul 15, 2003)

*Your car sounds different*

See page 55 at http://www.bimmernut.com/~micah/images/330zhp/9 part1 engine management.pdf

The event you descibe does not sound like the normal dip/surge at 4000 RPM when the intake runners switch over from long to short.


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## Solid (Feb 3, 2003)

I have the same problem, but i have a early `03 build date.



mtarchal said:


> Ok, I am really confused so I am starting a new thread. At 4000 rpm, I feel a hesitation when accelerating at a moderate amount. It is pretty close to the 4000rpm mark and it does not happen all the time, but it does. The car sputters/surges like 3 times when going past the 4000rpm mark.
> 
> Anyone else have this ? I am confident that there are others out there from reading.
> 
> ...


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## mtarchal (Aug 21, 2004)

What did you do about it or do you have any fixes, been to the dealer, called BMWNA ?



Solid said:


> I have the same problem, but i have a early `03 build date.


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## mtarchal (Aug 21, 2004)

Well I filed a complaint with BMWUSA. Anyone else filed a complaint about this ? 

Would you like to join in ?


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## kurichan (May 1, 2004)

I didn't have this problem and publicly rejoiced about it here. As punishment for that, the problem surfaced. In the process of getting some other things fixed, I mentioned the power dip to my SA. 

I just got a call. The head of service at my dealer now states that the 4,000 RPM power dip is a KNOWN problem for which BMW currently has no fix.


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## MicahO (Apr 19, 2004)

kurichan said:


> I didn't have this problem and publicly rejoiced about it here. As punishment for that, the problem surfaced. In the process of getting some other things fixed, I mentioned the power dip to my SA.
> 
> I just got a call. The head of service at my dealer now states that the 4,000 RPM power dip is a KNOWN problem for which BMW currently has no fix.


As someone noted above - the 'sputter' you are describing does not sound at all like the well-known 'dip' that occurs as the resonance system switches over. There is no 'fix' for the resonance system switch-over, as it is short and planned turbulence in the airstream. If you are feeling 'sputters,' you have another problem.

Tell your dealer to try, try again. Sounds like they either don't want to help, or you are overstating the impact of the resonance system dip (and from your history, I would not discount the latter). Either way, get another opinion.


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## stylinexpat (May 23, 2004)

*Try running some Union 76 race Gas..*

Fill up either 50-60% regular Super Unleaded Fuel and the rest with Racing Fuel from Union 76 And Also add a can of NOS Octane Booster street Version. Tell me how the car runs then. We have bad fuel here in the U.S., I think that with those new cams along with the Torque band the curren fuel is not good so there is a timing pull back .. Car should run better with this gas in it. The point though is that we paid enough money for this new car and it should have a proper ECU in it with proper software! This is a Software glitch that BMW needs to take responsibility for and fix period. That dip exists on stock car and is even more noticable on tuned cars that produce more Horsepower.


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## kurichan (May 1, 2004)

Mine spuddips.



MicahO said:


> ...or you are overstating the impact of the resonance system dip (and from your history, I would not discount the latter). Either way, get another opinion.


Let's see... You're judging the impact of the issues with my car from where? Based on my "history?" :rofl: Very interesting. Could you tell my what's wrong with my knee? It's a little sore... 

I told my SA "the power seems to drop off at 4,000 RPMs. Maybe it's just how the torque curve is, but when you drive it, could you just check it out?" He called and said the problem why very noticable and the he talked with the head of service. The head of service checked and was told BY BMW that it is a "known problem - no fix at this time."

Shall I scan and post the service record...


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## mtarchal (Aug 21, 2004)

*NOW KNOWN Problem*

Would you mind posting up which dealer stated this, "That it is a known problem and there is no fix at this time" , and what is the phone number to that dealer ?

I would encourage you to also call BMW USA and talk to the reps there about this same problem I have, so we can start to get BMW to do something about it. I did it already.
The more calls they get then they will have to look at it.

If there was a class action lawsuite about the stereo fading in and out, then I am sure this is more critical since it involves driving and acceleration issues, which can be dangerous.

BMW of America : Customer Relations 1-800-831-1117

********* ANYONE ELSE OUT THERE PLEASE DO THE SAME *********

If you guys want this problem fixed then do this... what is the alternative go under the lemon law (< 1 year old and I think < 15,000 miles) and get rid of the car ? I would rather them fix it ........

-2004 ZHP Owner



kurichan said:


> I didn't have this problem and publicly rejoiced about it here. As punishment for that, the problem surfaced. In the process of getting some other things fixed, I mentioned the power dip to my SA.
> 
> I just got a call. The head of service at my dealer now states that the 4,000 RPM power dip is a KNOWN problem for which BMW currently has no fix.


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## Double Vanos (Aug 20, 2003)

Sorry for your problem, but have you asked for the software updated? I thought that it would fix this. I had the ecu reprogram in my car upon delivery due to an engine problem when i bought the car. Ever since this baby rips all the way to the 6800 RPM limit as smooth as a Jet turbine and makes a killer noise that puts a smile on my face.  
Good luck and keep haggling your SA, i'm sure there's something he can do.


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## mtarchal (Aug 21, 2004)

*39.1 software / DMZ*

I assume you have 39.1 software version which as just been released ? Somehow I think possibly the side effect of having the DMZ programmed is a smoother acceleration at 4k, despite the lack of a service bulletin on this specific issue. We shall see, I am getting mine done today.

2004- zph


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## stylinexpat (May 23, 2004)

*Perhaps not all cars have this problems but*

most due it seems like. Waiting to get my software update. please update us if anyone got update and did any good..


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## mtarchal (Aug 21, 2004)

*39.1 Software / Get it*

Just had my ZHP updated DME/software version 39.1 which was just released. I will have to give it a few days and range of temperatues, seems like BMW's are picky and have an attitude toward weather - possibly, but it is SAFE TO SAY at this point driving and ripping into the 6000 rpm range (ripping in 2nd gear to pass the 4000rpm mark), going home from the dealer, I did NOT experience the hesitation and it was smooth as hell, felt different somehow. Don't know what to tell you but the hesitation does not always happen, will have to give it some time, but seems to be smoother.....

We shall see what tomorrow will bring. At any rate, newer software is always better.


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## kurichan (May 1, 2004)

mtarchal,

Did the dealer tell you that 39.1 specifically addresses the 4,000 RPM dip?


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## mtarchal (Aug 21, 2004)

*39.1 Software Release / Oct 04*

They just updated my software and thought it might help. There is no service bulletin on it in relation to the software update of 39.1. There was another guy on this forum that said he had it done and there are no problems. I seem to think that BMW might not know that the 39.1 software fixes or helps the problem, it might be a side effect of the update, or they might have fixed a problem they did not experience or know about.

I will let everyone know, let me drive it for a few days.


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## RChoudry (Jan 13, 2002)

my buddy had it done and he says the 4000 rpm hesitation is now gone. I never had it so I can't say.


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## mtarchal (Aug 21, 2004)

*39.1 Software Oct 04*

I would seem to agree with your buddy, my 4000 RPM hesitation is now gone also, just had the 39.1 update yesterday (Oct 8, 04).

It is smooth and steady and even not jerky now, hard to describe, but it seems like the car is solid and not 'spongy' also.

I will give it some time and then make sure BMWUSA knows of the complete screwup they have caused for alot of folks.

8000 miles later, it is like "well hello car", nice to finially meet you. Don't worry, BMW will hear about this one. I will also make sure the service manager talks to the engineers about this.

2004 zhp (Happy) owner


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## RChoudry (Jan 13, 2002)

good to hear.

I do have to ask, the only roughness I can feel now is the cooling fan coming on and off. It causes the driver's seat to conduct a vibration. That's about it. The roughness at lights is gone. Do you feel the fan coming on/off, say when in a garage or someplace relatively quiet?


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## Double Vanos (Aug 20, 2003)

Good to hear that you got the software update, hope your that your dip is over. This is a wonderful car, i just cant get enough of the way it rips! BMW should offer this software update to all ZHP owners.


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## stylinexpat (May 23, 2004)

*When mine gets the update , it is going on the DYNO*

This then will show the truth about 4000 RPM Dips. If there is a Dip on the DYNO after the software update then the dip is still there, if there isn't one on the DYNO then it's gone. Hope it goes away


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## mtarchal (Aug 21, 2004)

There is no more dip after I had the DME 39.1 software update. I have driven the car for about 2 days now and it is gone. 

Get the 39.1 software uploaded !


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## wheel-man (Sep 28, 2004)

mtarchal said:


> There is no more dip after I had the DME 39.1 software update. I have driven the car for about 2 days now and it is gone.
> 
> Get the 39.1 software uploaded !


should all with the zhp get the update? the dealer will be willing to do it?


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## dynosor (Jul 15, 2003)

*How about a before and after?*



stylinexpat said:


> This then will show the truth about 4000 RPM Dips. If there is a Dip on the DYNO after the software update then the dip is still there, if there isn't one on the DYNO then it's gone. Hope it goes away


How about a before and after?


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## mtarchal (Aug 21, 2004)

*39.1 Software Update*

It is one of those things, where BMW does not have (at least what they told me), a service bulletin on the 4k RPM acceleration drop problem. I just talked to my service guy and told him that people are getting it done and it seems to take care of the problem, and he said we will just do it to make you happy. The service guys do not know about all the problems since they deal with so many cars and problems, so in a way we are more in tune to the problems. BMW could also be lying because of embarassment or something, who knows.

Look at it this way, it will not hurt, and I work in the software industry and updates, patches are always good. But I believe in this forum there are 3 references to people that had it done and the problem went away and one guy even emailed me and told me that. There is a deler in CA that told me that the car has all new software in it, which in my opinion is buggy, and yes it was indeed.

I am sure they will do it. I plan on writing a letter to BMWUSA and telling them about my fading stereo and 4k rpm issues, don't worry, BMWUSA will hear about it. I was really not happy about it when I first discovered it, but my jets are cooling off now.

The car is now operating the way it should.


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## wheel-man (Sep 28, 2004)

thanks for the added info... when i pick up my ipod connector, i'll ask them for the update.

thanks again. :thumbup:


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## salvo (Feb 28, 2004)

I have the same problem with my NON-ZHP...does the 39.1 software upgrade still apply and did you guys just ask the SA to do it...I would anticipate a bunch of handwaving...
thanks


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## Solid (Feb 3, 2003)

I think it applies to anyone with the MS45 ECU, which means ZHP's and any 2004+ E46.


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