[isenc2]

Okay, so I have a bit of a different situations than most of yall. I do not currently experience bucking or stuttering, just a bit of rough idle on cold start and very rarely the car would hesitate just a little and during hard upshifts. Now, I have changed both of my solenoids just for preventative maintenance. The cold start idle is a lot smoother and the car shifts a lot smoother as well. I have changed all my fluids about 10k ago, engine oil changed every 5000miles and I run 0w30 LL-01FE bmw oem oil. This is definitely worth doing at around 70k miles. I bought them on FCP euro, and the swapped out old solenoids are interesting. Since in my case nothing is failing, both of them looked okay, however, one of them is just a little stuck, and slow to actuate, which makes sense.

[mixmastermike]

Originally Posted by isenc2

Okay, so I have a bit of a different situations than most of yall. I do not currently experience bucking or stuttering, just a bit of rough idle on cold start and very rarely the car would hesitate just a little and during hard upshifts. Now, I have changed both of my solenoids just for preventative maintenance. The cold start idle is a lot smoother and the car shifts a lot smoother as well. I have changed all my fluids about 10k ago, engine oil changed every 5000miles and I run 0w30 LL-01FE bmw oem oil. This is definitely worth doing at around 70k miles. I bought them on FCP euro, and the swapped out old solenoids are interesting. Since in my case nothing is failing, both of them looked okay, however, one of them is just a little stuck, and slow to actuate, which makes sense.

I think I'm going to give this a go, I cleaned my injectors last month and that made a huge difference in smoothness, I still have the timing correction issue tho.

Are both Intake and Exhaust Actuators the same part#?

[gantona]

Originally Posted by mixmastermike

I think I'm going to give this a go, I cleaned my injectors last month and that made a huge difference in smoothness, I still have the timing correction issue tho.

Are both Intake and Exhaust Actuators the same part#?

yes, same part number for exhaust and intake.

[isenc2]

Originally Posted by mixmastermike

I think I'm going to give this a go, I cleaned my injectors last month and that made a huge difference in smoothness, I still have the timing correction issue tho.

Are both Intake and Exhaust Actuators the same part#?

I got a question for ya, what symptoms were you experiencing before cleaning the injectors? I have not done anything to the injectors yet, but I am considering either cleaning or replacing.

[mixmastermike]

Originally Posted by isenc2

I got a question for ya, what symptoms were you experiencing before cleaning the injectors? I have not done anything to the injectors yet, but I am considering either cleaning or replacing.

Under acceleration my car was pulling quite weak, so I decided to take a look at the injectors. They were filthy with heavy carbon deposits and terrible spray patterns.

My work puts me in connection with a lot of repair shops and I spoke with a seasoned repair tech just before Christmas who said its a good idea to keep them clean as they're in the combustion chamber. So I thought that I'd buy a few pieces of kit and see if it made any difference, It did, she pulls a lot harder now. I'm on stage 2 MG flasher and it feels like the engine needs more fuel so I just bought a TU pump. It never ends lol.

However I still have the weird low RPM issues mentioned in the 'Bucking' thread. Hopefully new actuators will resolve that one....

[isenc2]

Originally Posted by mixmastermike

Under acceleration my car was pulling quite weak, so I decided to take a look at the injectors. They were filthy with heavy carbon deposits and terrible spray patterns.

My work puts me in connection with a lot of repair shops and I spoke with a seasoned repair tech just before Christmas who said its a good idea to keep them clean as there in the combustion chamber. So I thought that I'd buy a few pieces of kit and see if it made any difference, It did, she pulls a lot harder now. I'm on stage 2 MG flasher and it feels like the engine needs more fuel so I just bought a TU pump. It never ends lol.

However I still have the weird low RPM issues mentioned in the 'Bucking' thread. Hopefully new actuators will resolve that one....

I see, I have bought brand new injectors from Latvia and will get those in soon. I have noticed the car pulls a bit less, we'll see if it does anything. I always do preventative maintanance so I'm glad to catch the VANOS actuator going bad.

[ZHSD001A]

I have long been troubled by rough idle issue with my 2019 X3 M40i (gen1 B58). Just did my first datalog and noticed immediately that the ignition timing across all cylinders are not even, even though I have replaced new plugs and coil. Then I added the Vanos parameters into my log and found out both my intake Vanos and exhaust Vanos are completely off. Will try replacing both Vanos actuators.

[conejodenieve]

Wanted to add my experience to this thread in case it helps anybody out.

I recently started experiencing this bucking issue on my 340i. It felt exactly like others here mentioned. It felt like the transmission was slipping in lower RPMs and the car felt like it would hesitate for a split second. It's also worth noting that for a while now, I had been experiencing violent fuel cut and back fires at WOT at higher RPMs. I tried to run a log and check the VANOS but BM3 was showing the target and actual for intake and exhaust VANOS at having the same exact values. So it being what seems like a common issue and cheap fix, I replaced both VANOS solenoids. Man was that a pain. One of the clips fell out and luckily it hit the bottom pan but my hands were all cut up after the install was done. The car felt better but there was still that noticeable bucking and the fuel cut at WOT.
So next thing was the O2 sensors. They seem to be on backorder everywhere right now so the cheapest option I was able to find was both on carparts.com.
Just replaced them both today and took the car for a test drive. The car feels so much better so far! No more bucking and I did a couple of pulls and had no fuel cut whatsoever. The pre cat one was pretty fouled up. I've added a picture and I'm sure you guys can tell which one is the pre cat one lol.
My car has 114k miles and I've been running an ethanol blend with a high flow cat for a couple of years now so I'm not mad about having to spend the $140 on the VANOS for some extra peace of mind.
If the O2 sensors didn't fix the issue, my next step would've been getting the injectors service and a walnut blasting of the intake valves but since that is the most expensive of the services, I was holding off on it. I'm still going to get that done soon, but it's nice to know that I can wait just a bit longer.
Hope this helps someone out. The info already here was super helpful to me.

[cray101]

Originally Posted by conejodenieve

Wanted to add my experience to this thread in case it helps anybody out.

So next thing was the O2 sensors. They seem to be on backorder everywhere right now so the cheapest option I was able to find was both on carparts.com.
Just replaced them both today and took the car for a test drive. The car feels so much better so far! No more bucking and I did a couple of pulls and had no fuel cut whatsoever. The pre cat one was pretty fouled up. I've added a picture and I'm sure you guys can tell which one is the pre cat one lol.
My car has 114k miles and I've been running an ethanol blend with a high flow cat for a couple of years now so I'm not mad about having to spend the $140 on the VANOS for some extra peace of mind.

Thanks for posting that. I have been following this thread for a few months because I've got similar issues to what many others here do. Car slightly hesitates at low rpm cruising speeds. Mostly noticeable at highway speeds. I've thought about doing the VANOS replacement, but would prefer to be able to log it. I run bootmod3 stage 1 with stock DP. According to a few posts here, it sounds like there's an issue with bm3 maybe not reporting VANOS right with their logging. About a month ago I got a random CEL that was for pre-cat O2 sensor, but cleared it and it never came back. Wonder if that's maybe the cause of my issue. Car only has 50k miles though compared to yours over 100k

[mixmastermike]

Originally Posted by conejodenieve

Wanted to add my experience to this thread in case it helps anybody out.

I recently started experiencing this bucking issue on my 340i. It felt exactly like others here mentioned. It felt like the transmission was slipping in lower RPMs and the car felt like it would hesitate for a split second. It's also worth noting that for a while now, I had been experiencing violent fuel cut and back fires at WOT at higher RPMs. I tried to run a log and check the VANOS but BM3 was showing the target and actual for intake and exhaust VANOS at having the same exact values. So it being what seems like a common issue and cheap fix, I replaced both VANOS solenoids. Man was that a pain. One of the clips fell out and luckily it hit the bottom pan but my hands were all cut up after the install was done. The car felt better but there was still that noticeable bucking and the fuel cut at WOT.
So next thing was the O2 sensors. They seem to be on backorder everywhere right now so the cheapest option I was able to find was both on carparts.com.
Just replaced them both today and took the car for a test drive. The car feels so much better so far! No more bucking and I did a couple of pulls and had no fuel cut whatsoever. The pre cat one was pretty fouled up. I've added a picture and I'm sure you guys can tell which one is the pre cat one lol.
My car has 114k miles and I've been running an ethanol blend with a high flow cat for a couple of years now so I'm not mad about having to spend the $140 on the VANOS for some extra peace of mind.
If the O2 sensors didn't fix the issue, my next step would've been getting the injectors service and a walnut blasting of the intake valves but since that is the most expensive of the services, I was holding off on it. I'm still going to get that done soon, but it's nice to know that I can wait just a bit longer.
Hope this helps someone out. The info already here was super helpful to me.

O2 Sensors did the trick for me as well.

I did Vanos solenoids, cleaned my injectors and then the O2 sensors.

Car feels so smooth, just like you every job made the car better.

[gasoline]

Originally Posted by VVlasy

Hey guys,
I have noticed, now for maybe half a year, something that I thought was transmission slipping. But I found out it could be the engine doing something called "bucking".

Usually when I am in comfort, going a slight incline with light throttle (1100-1200ish rpms), I could notice slight dips in RPMs every second or so than can also be felt as a slight jolt, if I applied more throttle, all would be fine. I was thinking all the time it was the transmission or transfer case slipping.

Anyone has any insight on this? It is kinda hard to replicate so I am hesitant ATM to bring it to dealer, until I can safely reproduce this.

SOLVED:

Big thanks go to Robs335iproblems for digging deep and finding the cause

The problem is caused by faulty VANOS actuators (P/N 11367614288 (#11)). There are two of them, one on the exhaust side, one intake. I personally recommend replacing both of them, for the price they are (60$ish) and the effort you are putting in, you might as well do both. Or you can go through data logging to figure out which one it is.

Video guide by mevans

A few tips from me:

• Get a short stubby flathead screwdriver (seen in video from mevans313 ) I had a friend lend me one he has from his dad, probably 30 years old, but for getting out the passenger side actuator is almost impossible without this.
• When you get the actuator turned about a inch-two inches, and it wont go anymore with your hand or the screw driver. Try to pry it off a bit and then keep turning, it will release real easy that way. it took me half an hour to realize this.
• Also be careful not to drop those metal clips that face downwards. Its a real PITA to get back in. Nigh impossible if you have bigger sized hands.

This may also be a solution to a number of other issues, which you might think are coming from the transmission such as:

• Rough 1-2 shift on cold start
• Hard shifts in sport, especially hard in sport+ (feels like stage 3 xHP, without xHP )
• Hard downshifts (mainly 1st and 2nd gear)
• Jerking when applying and releasing throttle (a single jerk, like the engine mounts are bad), very rough in 1st and 2nd gear when torque converter isn't locked, but happens in any gear
• delayed throttle response (bogging on initial throttle)

Please note that some users solved their issues by replacing O2 (lambda) sensors. Also quite cheap and easy to do, so don't give up hope if the actuators don't solve it for you.

Hello,
I have a B48 530i, with very similar problem like you stated, just trying to understand whether I am seeking it in the right point.
Especially on uphill, when I try to increase the speed and keep the throttle constant, the car accelerates but instead of a smooth increase it makes it gradually or intermittently like in 2 seconds period; as if I press the throttle once in 2 seconds and release it and again press it and…so on. I see this behavior also as torque fluctuation in sport gauges in the same time the car pulls and releases.
Is this the problem you have? After I red your solution I am planning to have vanos actuators replaced.

[gantona]

Originally Posted by gasoline

Hello,
I have a B48 530i, with very similar problem like you stated, just trying to understand whether I am seeking it in the right point.
Especially on uphill, when I try to increase the speed and keep the throttle constant, the car accelerates but instead of a smooth increase it makes it gradually or intermittently like in 2 seconds period; as if I press the throttle once in 2 seconds and release it and again press it and…so on. I see this behavior also as torque fluctuation in sport gauges in the same time the car pulls and releases.
Is this the problem you have? After I red your solution I am planning to have vanos actuators replaced.

Pretty much the exact same think I had on my b58
Not so complex to do, go for it. You will be amazed how the car runs after

[gasoline]

Originally Posted by gantona

Pretty much the exact same think I had on my b58
Not so complex to do, go for it. You will be amazed how the car runs after

Thx gantona, I will have it done.

[MAMSport]

Just wondering here. Are the VANOS solenoids getting dirty due to extended oil change intervals vs. the owners who change oil/filter closer to 5k mile intervals?

[gasoline]

Originally Posted by gasoline

Thx gantona, I will have it done.

Hi, thanks for your comments, my vanos actuators were replaced today and finally the problem is solved!

[DieselDuck]

Very interesting topic. Although not having any severe problems I do experience some of the symptoms of vanos actuators going bad.

- The "wavy" torque feeling (and you can hear the difference in surge also) while going up a hill in low rpm @ partial throttle.

- rough'ish shift from 1 to 2

- in sport+ / sport the shifts seem kinda harsh sometimes (to the point where I fiddled a bit with tq reduction settings in xhp, all adaptation values in xhp app are good btw)

- After a gearshift on WOT in manual mode it does feel like it hesitates (sometimes) and then boost comes back


Most of the time the car drives okay and in my last logs everything was perfectly fine however I did not log the vanos values. I think if I will I will find some oddities concerning the vanos after having read everything here.

What do you guys think ?

Probably gonna take them with in my next upcoming service which is anytime soon now, luckily it seems pretty cheap and not so hard to install

[gasoline]

Originally Posted by DieselDuck

Very interesting topic. Although not having any severe problems I do experience some of the symptoms of vanos actuators going bad.

- The "wavy" torque feeling (and you can hear the difference in surge also) while going up a hill in low rpm @ partial throttle.

- rough'ish shift from 1 to 2

- in sport+ / sport the shifts seem kinda harsh sometimes (to the point where I fiddled a bit with tq reduction settings in xhp, all adaptation values in xhp app are good btw)

- After a gearshift on WOT in manual mode it does feel like it hesitates (sometimes) and then boost comes back


Most of the time the car drives okay and in my last logs everything was perfectly fine however I did not log the vanos values. I think if I will I will find some oddities concerning the vanos after having read everything here.

What do you guys think ?

Probably gonna take them with in my next upcoming service which is anytime soon now, luckily it seems pretty cheap and not so hard to install

I had exactly the same symptoms and after I red this thread, I did not even take the logs of vanos and got them replaced. Many thanks to whom discovered the cause.
Before this, nearly all of the mechanics I asked blamed the transmission in the first place since many of them know only usual cases and it is hard to describe this problem. They did not even feel this fluctuation because this happens on specific conditions like uphill and moderate throttle, but they test it with their own driving style and say “I do not sense any problem”, so, it is again us to check whether it is solved or not.
I think yours will also be solved after replacement.

[DieselDuck]

Originally Posted by gasoline

I had exactly the same symptoms and after I red this thread, I did not even take the logs of vanos and got them replaced. Many thanks to whom discovered the cause.
Before this, nearly all of the mechanics I asked blamed the transmission in the first place since many of them know only usual cases and it is hard to describe this problem. They did not even feel this fluctuation because this happens on specific conditions like uphill and moderate throttle, but they test it with their own driving style and say “I do not sense any problem”, so, it is again us to check whether it is solved or not.
I think yours will also be solved after replacement.

How many km's do you have ? I'm still pretty low, like 65k km's, and I feel like it has been doing this for a very long time, just never really bothered too much about it thinking it was "normal".

[gasoline]

Originally Posted by DieselDuck

How many km's do you have ? I'm still pretty low, like 65k km's, and I feel like it has been doing this for a very long time, just never really bothered too much about it thinking it was "normal".

Mine is 106k km’s. My previous car was F30 320d and I was just hearing this “wavy” drive from the engine sometimes but interestingly I did not feel any jerking. However with this car (B48 engine) I felt the annoying shaking/jerking feeling and decided to go for it.
An additional info; I felt it much worse in cold days compared to warmer days. So maybe you could feel it at relatively low km if you live in a cold climate place.

[gantona]

Edit :
Wot is NOT affected by vanos, since variable timing at wot push valves at the maximum.
You strongly feel any issue when using low throttle, trying to accelerate smoothly.
This is where variable timing works thru vanos actuators.

When you remove your old actuators, you will notice the small bit goes down slowly when facing down.
The brand new ones are moving freely/fast

I’m almost sure it’s due to engine oil dirts stucked within actuators leading to slow operation,
Generating at the end lot of vanos corrections by engine management, to reach proper position.
Pretty simple swap (with small hands…).
Not a big deal

[DieselDuck]

My in. vs ex. vanos values in log

The ex one is clearly f**d so my assumptions seem right

[Fast_Rabbi]

Old : https://youtube.com/shorts/pjxU31kcpM4?feature=share

Vs

New : https://youtube.com/shorts/LIBxKQzcDeg?feature=share

So yeah log it and change it.

It was a really pain pain job ! Lost a clip. Have to bought a new one.
Was really painful to put the new one because I got small but big hands and you don't have any space to work.