Engine hesitation from 3000 rpm to 4000 rpm on 2003 Z4 3.0i

M54B30 · 03-02-2015, 07:49 PM

Hello all,

I did quite extensive search regarding this issue on my M54B30 engine but I haven't found any that addresses my specific issue.

I don't know when I started to notice this issue but the engine seems to be struggling going from 3000 to 4000 rpm.
Under full throttle power comes on smooth, but it happens when I give it about 70% of throttle.
It happens when engine is warmed up and I'm not sure if it happened while engine is still cold.

I talked to my buddy who owns 330Ci ZHP and he thinks it could be VANOS or MAF issue.

No errors or check engine lights turned on. The car runs perfect aisde from that RPM range.

I'm planning on taking the car to a nearby BMW mechanic but I'd like to know what might be causing the issue before I take it to the shop.

Thanks in advance for any inputs/insights!

Steeler · 03-02-2015, 07:56 PM

MAF is my best guess.
Had the same symptoms on my car same revs, swapped out the MAF, all good

Huz-Z · 03-03-2015, 07:21 AM

Sounds like your spark plugs are dirty and need replacing.

RADRACR · 03-03-2015, 08:39 AM

I've had issues like this over the years on German cars.
Check MAF, Coils, Spark Plugs, in that order. After that, fuel pump relay and filter.

torchmedia · 03-03-2015, 08:53 AM

I had the same issue last fall, it ended up being a bad 02 sensor for me.

t0pless · 03-04-2015, 01:07 PM

Sounds like the DISA valve.

The DISA valve is essentially a valve in the intake runners that allow dynamic change in runner length. Look at the attached images below. At idle, you should be able to hear it rattling around. Usually these go around 60-80k miles. Don't bother about getting another OEM- they will break. Use the GAS solution posted below. Also, be careful removing the DISA. If it is really worn, there is a metal pin that can fall out into your intake runners. DO NOT start the car until you can find it. Some believe that the metal pin can fall out even without removing the DISA. I have to disagree as the pin is pressed against the housing of the intake runner. Replacing this will help with idle and smooth out your torque curve. If you plan on making a racing application, some people consider deleting the DISA valve. A missing/unplugged/broken DISA valve will NOT throw a code with an exception of maybe a lean code.

http://germanautosolutions.com/bmw_s...repair_kit.php

RevsPlease · 03-06-2015, 01:41 AM

The Vanos seals in the m54bxx are extremely prone to failure. When they've gone bad you will have some hesitation or jerkiness in that RPM range, usually under part throttle. I don't know if I'd describe it as "struggling", so that may or may not be your issue. My car has this problem, and where the jerkiness occurs you can also hear a kind of rattle with the Vanos changing timing. The DIY to fix this problem is cheap (you just need new seals --Beisan Systems makes a kit), albeit potentially challenging based on your skill level.

As other members have already stated, other culprits may be:
- DISA Valve. Remove it, clean it (it WILL be dirty as all hell), inspect and test vacuum pot as well as the pin that holds the flap in place. If the pin is wobbling out of the housing you need to replace it (Google DISA repair kit). If the pin is missing YOU NEED TO FIND IT BEFORE YOU START THAT ENGINE. If the vacuum pot doesn't hold vacuum you need to replace the whole unit.
- MAF. Remove it and clean it with some MAF cleaner.
- Spark plugs
- Coils
.etc .etc

03-02-2015, 07:49 PM	#1
M54B30 New Member 5 Rep 9 Posts Drives: 2003 Z4 3.0i Join Date: Feb 2015 Location: United States iTrader: (0)	Engine hesitation from 3000 rpm to 4000 rpm on 2003 Z4 3.0i Hello all, I did quite extensive search regarding this issue on my M54B30 engine but I haven't found any that addresses my specific issue. I don't know when I started to notice this issue but the engine seems to be struggling going from 3000 to 4000 rpm. Under full throttle power comes on smooth, but it happens when I give it about 70% of throttle. It happens when engine is warmed up and I'm not sure if it happened while engine is still cold. I talked to my buddy who owns 330Ci ZHP and he thinks it could be VANOS or MAF issue. No errors or check engine lights turned on. The car runs perfect aisde from that RPM range. I'm planning on taking the car to a nearby BMW mechanic but I'd like to know what might be causing the issue before I take it to the shop. Thanks in advance for any inputs/insights!
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03-02-2015, 07:56 PM	#2
Steeler Colonel 2429 Rep 2,704 Posts Drives: Built not Bought 04 Z4 VF Join Date: Feb 2013 Location: Kitchener Ontario Canada iTrader: (2)	MAF is my best guess. Had the same symptoms on my car same revs, swapped out the MAF, all good __________________ W2A Intercooled Vortech V3Si, custom ducting, Alpha N, 60# Bosch,2.62 pulley, multi port WMI, Severn Tuning(pokeybritches), Tial, magnaflow,SS race muffler, 42 design,3.91LSD, H&R, Hotchkis,ST coils,Konis, Megan camber arms, AKG SS, Nylon mounts, Poly bushings, Carbon interior, CF Aero.APEX
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03-03-2015, 07:21 AM	#3
Huz-Z Brigadier General 851 Rep 4,057 Posts Drives: Z4 3.0si, 328 XDrive, X5 35i Join Date: Aug 2009 Location: Canada iTrader: (0)	Sounds like your spark plugs are dirty and need replacing. __________________ Huz-Z BMW Z4 3.0si Roadster. Montego Blue Metallic. Premium and Sport Package.
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03-03-2015, 08:39 AM	#4
RADRACR Captain 84 Rep 924 Posts Drives: '08 Z4 M Coupé // '09 X5 d Join Date: Apr 2010 Location: Sioux Falls, South Dakota iTrader: (2)	I've had issues like this over the years on German cars. Check MAF, Coils, Spark Plugs, in that order. After that, fuel pump relay and filter. __________________ '08 Z4 ///M Coupé (#1765/1815) — 1 of 68 Sepang Bronze / Black Nappa / Madeira Wood / 1 of 1 this combo 19" Advan RS / AP Racing / Bridgestone RE-11 / Autosolutions SSK / R.E. Diablo / R.E. trans mounts '09 X5 35d — Space Grey / Saddle Brown 20" Forgestar F14 / SCR Delete
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03-03-2015, 08:53 AM	#5
torchmedia Second Lieutenant 53 Rep 268 Posts Drives: White Z4MC Join Date: Jul 2014 Location: Canada iTrader: (0)	I had the same issue last fall, it ended up being a bad 02 sensor for me.
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03-04-2015, 01:07 PM	#6
t0pless Private 20 Rep 52 Posts Drives: 2003 Z4 3.0 Join Date: Oct 2013 Location: United States iTrader: (0)	Sounds like the DISA valve. The DISA valve is essentially a valve in the intake runners that allow dynamic change in runner length. Look at the attached images below. At idle, you should be able to hear it rattling around. Usually these go around 60-80k miles. Don't bother about getting another OEM- they will break. Use the GAS solution posted below. Also, be careful removing the DISA. If it is really worn, there is a metal pin that can fall out into your intake runners. DO NOT start the car until you can find it. Some believe that the metal pin can fall out even without removing the DISA. I have to disagree as the pin is pressed against the housing of the intake runner. Replacing this will help with idle and smooth out your torque curve. If you plan on making a racing application, some people consider deleting the DISA valve. A missing/unplugged/broken DISA valve will NOT throw a code with an exception of maybe a lean code. http://germanautosolutions.com/bmw_s...repair_kit.php Attached Images Last edited by t0pless; 03-04-2015 at 01:14 PM..
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03-06-2015, 01:41 AM	#7
RevsPlease Private First Class 10 Rep 167 Posts Drives: 2003 Z4 3.0i, Black Saphire Join Date: May 2011 Location: Portland, Oregon iTrader: (0) Garage List 2003 BMW Z4 3.0i [10.00]	The Vanos seals in the m54bxx are extremely prone to failure. When they've gone bad you will have some hesitation or jerkiness in that RPM range, usually under part throttle. I don't know if I'd describe it as "struggling", so that may or may not be your issue. My car has this problem, and where the jerkiness occurs you can also hear a kind of rattle with the Vanos changing timing. The DIY to fix this problem is cheap (you just need new seals --Beisan Systems makes a kit), albeit potentially challenging based on your skill level. As other members have already stated, other culprits may be: - DISA Valve. Remove it, clean it (it WILL be dirty as all hell), inspect and test vacuum pot as well as the pin that holds the flap in place. If the pin is wobbling out of the housing you need to replace it (Google DISA repair kit). If the pin is missing YOU NEED TO FIND IT BEFORE YOU START THAT ENGINE. If the vacuum pot doesn't hold vacuum you need to replace the whole unit. - MAF. Remove it and clean it with some MAF cleaner. - Spark plugs - Coils .etc .etc
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