[Tag]

Originally Posted by AnieG

I'm pretty sure my 2011 335i is doing the same thing as described here.
Background:

About 5 weeks ago my car was surging all over the place. No pattern to follow, and I was stumped. The batter would take a charge and the car would be fine, until I parked it and it would be dead again. The batter indicated that it was still good. I posted on the BMW 335i Facebook page and here as well and the solution was clear - need a new battery. I bought a battery that had the same specs as the bad one. Car worked great for 1 day and then back to the same issue. Except now charging or jumping doesn't get me anywhere. Apparently me driving around for months with a bad battery caused strain on my Starter, which is now bad. I replaced the starter and everything was great.

Yesterday I started the car in the morning to let it warm up before work and it choked and died. I restarted, gave it some gas, felt it stumble a bit but it came around. I figured it was probably due to the weather and went to work. The bucking and surging was ridiculous. The bucking feels almost like my transmission is falling out. It's pretty bad. When taking off from a stop sign, the car stumbles and will sometimes get stuck in 2nd gear. I got a Limp Mode indicator yesterday driving home from work.
When I got home I checked the codes, nothing. I checked the oil and other fluids and my oil was about a quart low so I replaced that. No change.
I took the day off today and went car shopping. I'm afraid it's time to turn this one in. So sad...I love my car!

We are checking the plugs now to see if they look like they need replaced.

Unrelated Q: If the battery specs are the same, do you have to register the battery?

This is one of those though issues, it could be mechanical or software related. Not sure what you're going to find looking at plugs. If you were having misfires you might see a plug that looked sooty, but from what you're describing it's not misfiring. If it were you'd feel a jolt and see an RPM blip. Most common causes of misfires tend to be bad gas, bad plug/s, bad coil/s, bad injector/s or the HPFP.

I have a 335is with DCT and can say that I've seen weird RPM fluctuations due to the ECU. I believe mine were related to adaptations getting out of whack over time. I've had adaptations reset a couple of times, because the car was sluggish or herky jerky and acting weird which fixed the issue both times. The only time I've had any RPM surging where the needle was just wildly going up and down was because of a bad HPFP. It threw codes and kept going into limp mode.

I've also seen the car act weird when the battery was getting low. In fact I just changed my battery a couple of weeks ago and some of the weirdness I had been having over the past couple of months are now gone. The car fires up instantly now too. I've never had some of the other symptoms described in this thread so can't comment on them. I'd double check with a different code reader to make sure there aren't any. If you're still not seeing any fault codes I recommend you take the car on an open road and go WOT. That usually puts enough strain on the engine to throw a code.

Concerning the battery, yes, you'll need to register it if you want it to last. Otherwise the car thinks it's charging an older battery. If you put a different spec battery (i.e. not having the same CCA, CA, Reserve Capacity, etc) you risk either not charging it enough or overcharging it and leaking acid.

[Omni]

Just a quick note on my experience with this problem.

I had the bucking and surging at 2700-3200 rpm range for several months. Nearly drove me insane.

Replaced every part mentioned in previous posts—DV, Ignition Coils, Plugs, PCV. Blasted Intake. All vacuum hoses/connections... you get the picture.

I updated the DME, and all fuel delivery related modules, reset adaptations.

After all of this there was still a tiny bit of a surge at the aforementioned RPM range. Enough to be annoying.

-----------

One last thing I looked at was the CCV check valve at the top rear of the valve cover. I took it out, and noticed that it was no longer closing properly from boosted side of the valve. So it was leaking boosted pressure into the crank case.

I ordered a new one ($30 from dealer - with hose and fittings) and the problem is 100% gone. Car runs like new.

[Monster900]

Originally Posted by Monster900

I'm getting exact same thing Let the troubleshooting begin.

Update: surging is gone with colder weather.

[Omni]

Originally Posted by Omni

Just a quick note on my experience with this problem.

I had the bucking and surging at 2700-3200 rpm range for several months. Nearly drove me insane.

Replaced every part mentioned in previous posts—DV, Ignition Coils, Plugs, PCV. Blasted Intake. All vacuum hoses/connections... you get the picture.

I updated the DME, and all fuel delivery related modules, reset adaptations.

After all of this there was still a tiny bit of a surge at the aforementioned RPM range. Enough to be annoying.

-----------

One last thing I looked at was the CCV check valve at the top rear of the valve cover. I took it out, and noticed that it was no longer closing properly from boosted side of the valve. So it was leaking boosted pressure into the crank case.

I ordered a new one ($30 from dealer - with hose and fittings) and the problem is 100% gone. Car runs like new.

Update: I spoke too soon. Problem persists. I think it was the cold weather that made it seem like the problem was gone. If it gets below 10 degrees Fahrenheit, it seems to be gone. When it warms up, it's back.

[camMCLEAN]

bump!!!

Any updates on this? I am another one suffering with this.

is there any cures to this? you guys all have my exact same issue

08 335i 6AT, FBO -inlets. all maintenance done, index 12 injectors, fresh plugs, walnut blasted car ran fine until this week started this surging and i can't pin point it! i've done everything except take it to the dealer to reset the ECU like some talked about doing in here.

[racermp]

so is everyone here feeling this in summer only, between 2700-3500 rpm or so?

i logged it in MHD, does your car feel like this, boost, then no boost, then boost then no boost every 1/2 second or so?

http://datazap.me/u/racermp/e70-x5-s...&data=3-4-7-21

[terryd5150]

To those looking for the answer:

Reset engine adaptations.

This can be done with various tuning/troubleshooting software without taking to the dealership.

I used the Schwaben scan tool from ECS, but INPA and other programs work as well.

I remember this thread when it was active; there were multiple threads going on the topic at that time. The answer appeared in another thread. IRRC, the solution was originally posted by cwarren .

[fredcase]

Thread bump, mine does this also when it's a little warmer out.

[Monster900]

Originally Posted by terryd5150

To those looking for the answer:

Reset engine adaptations.

This can be done with various tuning/troubleshooting software without taking to the dealership.

I used the Schwaben scan tool from ECS, but INPA and other programs work as well.

I remember this thread when it was active; there were multiple threads going on the topic at that time. The answer appeared in another thread. IRRC, the solution was originally posted by cwarren .

+1 This seemed to cure my problem. Will see how long it will last.

[Maestro]

I am going to add to this conversation. Because my situation seem a little different since my issue showed after doing all the work other did to get rid of the problem.

I have a 07 335I MT with 168K miles, no tunes, just stock since it appears some people with the this issue had tunes in the car. My car has always run like a charm, never had issues with the car other than normal wear and tear type of things. The car was due for a major maintenance marathon, so I parked the car in Feb since I was concern about doing more damage to the car and began ordering parts.

Over the last three weeks, I replaced, plugs, coils, value cover and gasket (oil leaking all over the turbos, fire hazard). While torn apart, I replace the 6 rubber gaskets on the intake, replace the throttle body rubber gasket. Cleaned the throttle body since it was covered in burned on oil. Walnut blasted the intakes values, (there was so much burned on oil the ports were barely open should have done it on the last plug change not sure how it was even running).

Beside all the engine work, replace front shock (completely toast) and did front and rear brakes.

During the course of all the engine work I broke a few plastic vacuum lines, so replaced them.

After all that put it back together and the car fired right up took it for a short ride no issues. I always worry with the 335I that it will not start up or have weird issues like you always read about.

After all the work I let is sit, it needed new tires all the way around which are arriving today. Last week the wife drove it to the store and said it was bucking, thought it was odd, thought maybe on vacuum lines came off or the BOV was not put on correctly since I have seen that problem. Took the car out for a ride yesterday and it was not bucking it had pulsing throttle people are reporting here. I can tell you it happens at 2800 to 3000 RPM whether under load or not. If you hold the throttle at 2800 it will pulse up and down between 2800 and 3000. If you hard throttle, you do not even notice it. But light throttle, and holding speed at 2800 RPM it will rip your head off with it surging forward.

At this point I am not sure why this all of sudden happen. The car was fine and now it has new parts and started this issue. Some people said the had O2 sensor issue, which could and the issue with 168K miles and sitting for 3 months, did try blow out the carbon this morning and put new gas in. I am also thinking resetting adaptive setting since the car is use to all the crap in the intakes.

I do not want to go down the path of just replacing parts, what is the best course to solve this problem. I have read too many people just shot gunning replacing parts hoping the problem goes away.

[Sachak]

Just read this thread from start to finish.

I have been troubleshooting this problem for over a year now and I think I may have fixed it.

Recently for around 2 months now if I go out and drive my car for around 30 - 45 mins during the day in the heat and come to a stop in traffic or park the car and let it idle I get a fuel pump error pop up on the idrive telling me the car might stall and have reduced power and shortly after that message the car would stall.

I assumed it was the hpfp as I was having long cranks and rough idle from time to time and hpfp error codes too, so I ordered a brand new HPFP and fitted it and went for a drive, came home and boom the error popped up and the car stalled!

I did some research and found out about the EKP Module which controls the LPFP, I found out that these things have a mosfet chip that over heats badly and causes all sorts of issues, so I went out and bought a CPU fan and a little heat sink for the mosfet chip, I used my dremel to cut vents and a hole for the fan, used heat paste for the heat sink and mosfet chip, put it all back together and the problem is now gone!

Also I have not had any surging since doing this, Could this be the issue? I read that many of you complained that you have this problem in the summer time and when its cold it happens allot less or not at all.

The EKP module revision 3 has a heatsink on the back that makes contact with the body of the car. I have the EKPM3 and when I accessed it for the first time it was so hot I could hardly touch it and that was after taking my car apart to get to it so it had time to cool down! now with the fan and heat sink on the chip itself its cool to the touch even when I drove today in 27 degrees Celsius weather for a good hour to see if it would cut out on me.

[jwebs22]

I have been having a bucking and surging issue for what feels like forever, like most others I have been searching for a fix, love the car. So if anyone can help I would really appreciate it. it seems that it happens throughout the acceleration range and has a rough idle to start...sometimes... list of mods and what has been replaced below

JB4 Tune
Charge pipe and BOV
New injectors
New plugs
New coil packs
cleaned intake, replaced manifold gaskets
replaced leaking vacuum lines
New starter ground wire
Oil filter housing gasket
Throttle body gasket
Burger intake
Catch can
Oil pan gasket

I can log some runs and post them on here if it helps along in the process. I notice some were saying stuck diverter vales but didnt see if replacing that helped anyone else. Also, Im smelling a little bit of exhaust in the cabin now that its stating to get cold here in the northeast. thanks in advance for any help.

[thormessiah]

I’m having similar issues as well. Just got a walnut blast, new index 12s and full transmission maintenance and the problem is still there. How do I reset the adaptations? Anything I should be worried about?

[techwhiz]

I have the same issue. Mine is a power steering pump with high drag.
Yank the steering wheel. You might be able to affect it with steering wheel position or sudden movements of the wheel.

Walnut blast, bth fuel pumps and fuel regulator, plugs, etc.
Still has the issue, can only be affected by the steering wheel.

[thormessiah]

Originally Posted by techwhiz

I have the same issue. Mine is a power steering pump with high drag.
Yank the steering wheel. You might be able to affect it with steering wheel position or sudden movements of the wheel.

Walnut blast, bth fuel pumps and fuel regulator, plugs, etc.
Still has the issue, can only be affected by the steering wheel.

Gita a walnut blast like 3 months ago, not getting any fuel pump related codes... it didn’t start helping until After I got a malfunctioning injector so I felt life it’s related

[thormessiah]

Open to suggestions lol

[trading10]

Originally Posted by Osirs

Just read this thread from start to finish.

I have been troubleshooting this problem for over a year now and I think I may have fixed it.

Recently for around 2 months now if I go out and drive my car for around 30 - 45 mins during the day in the heat and come to a stop in traffic or park the car and let it idle I get a fuel pump error pop up on the idrive telling me the car might stall and have reduced power and shortly after that message the car would stall.

I assumed it was the hpfp as I was having long cranks and rough idle from time to time and hpfp error codes too, so I ordered a brand new HPFP and fitted it and went for a drive, came home and boom the error popped up and the car stalled!

I did some research and found out about the EKP Module which controls the LPFP, I found out that these things have a mosfet chip that over heats badly and causes all sorts of issues, so I went out and bought a CPU fan and a little heat sink for the mosfet chip, I used my dremel to cut vents and a hole for the fan, used heat paste for the heat sink and mosfet chip, put it all back together and the problem is now gone!

Also I have not had any surging since doing this, Could this be the issue? I read that many of you complained that you have this problem in the summer time and when its cold it happens allot less or not at all.

The EKP module revision 3 has a heatsink on the back that makes contact with the body of the car. I have the EKPM3 and when I accessed it for the first time it was so hot I could hardly touch it and that was after taking my car apart to get to it so it had time to cool down! now with the fan and heat sink on the chip itself its cool to the touch even when I drove today in 27 degrees Celsius weather for a good hour to see if it would cut out on me.

07 335i coupe 6MT stock everything.
Same issue as others in this big thread - bucking and surging, particularly when first starting to drive in the morning (engine cold) - cooler outdoor temps make the surging worse, but after a short amount of driving, the bucking and surging isn't as noticeable.


I'm most interested in this EKP module overheat condition being resolved with a heat sink and fan. However, it seems that this mosfet chip would be at it's coldest when the engine is cold and just starting to drive to work in the morning. Wouldn't the mosfet get hotter as the engine warms up??

I have used MHD, but am running stock map with no MHD installed. Problems were greatly reduced after returning to stock map. After replacing a coolant hose, and taking it for a test drive afterward to get the water temp up to 219 degrees, and oil temp up to 200, bucking isn't super bad. For this test drive, I used MHD to log data. What I noticed was cylinder 1 correction was bouncing around from 0 to 6 at idle, up to maybe 2500 rpms. If I punch it in 3rd gear, or even 50% throttle, correction is steady. I don't know what symptoms the LPFP can exhibit, but if this EKP module is causing the LPFP to malfunction, then I will either ask the dealer for the newer one you mentioned above (EPKM3), or modify the existing one if it is running super hot as yours was. Resetting adaptations has helped with a few things in the past, but from what I've read throughout this thread is people are replacing many parts without solving the underlying issue.

Not sure if it matters, but I am seeing a shadow code about the crank position sensor, "DME Shadow (inactive) codes - 2FDB crankshaft sensor signal no plausible". The active code I'm seeing is "2DED -DME: Power management closed circuit current violation". I also had the car in for an oil change at the dealership, and noticed they must have reset a few things - not sure if they would have disconnected the battery and coded it. Seat memory settings were wiped out, but radio station memory was unaffected.

Has anyone else looked into the EPKM3 revision 3 mosfet chip on the LPFP as a working solution?

[autoart]

anyone change the throttle body?

[Monster900]

Originally Posted by Monster900

+1 This seemed to cure my problem. Will see how long it will last.

Surging hasn't returned. All is perfect.

[Empire087]

Well i just got my mhd setup, time to go ahead and reset my engine adaptations and hopefully solves this problem. First warm day here in wisconsin, and bam its doing that. Weird. Also sorry for the necro, but its good to see ongoing posts, and this was one of the only ones that came up.

[Bearvt]

been reading the thousands of frustrated posts about bucking & surging. bmw acts like they never heard of it, dunn know nuttin".
I did as many have, plugs, mafs, coils and on and on. Fortunately I didnt fall for the dealer recommendation to replace the DME. I felt it was a rotational issue and pursued drivetrain. Hence (always wanted to use the word) the transfer case had 2 drops of fluid in it. it only holds 1/2 liter. the golden liter of DTF1 is $79.99 from the dealer or around $56 from FCP. Shell produces it for BMW. after draining what little was there i wasted half the liter rinsing the transfer of the grind that had been created. then Filled the transfer with the remaining 1/2 liter and the problem has disappeared and has not returned. went from hating my car to loving it again do this and stop wasting your money on diagnosis and parts that you dont need.
best to you
let me know
btw
csf intercooler, afe intake, slightly modified exhaust, cobb charge pipe, cobb stage 2 aggressive tune. its a rocket with no buck
love it

[Bearvt]

E93 bucking and surging. ITS NOT THE ENGINE. ITS A DRY TRANSFER. 2 WEEKS AND A PERFECT RUN