[DaanBMW]

Originally Posted by PhaseP

You may have fuel delivery problem pump or regulator. Fuel pressure measurement on the fuel rail may shed some light.

How do you do that on a moving car ? Since I've no symptoms at idle.

[chriscpmtmp]

I read through this post. I think I have similar issues in my 2011 328 xdrive. I notice roughness when it starts, and some weird shifting. I didn't break it down as much as some others. I do think it clunks into reverse if the car is trying to find the idle after a cold start. We usually count to 10, then go. If not, it tends to clunk an pulsate.

I bought it as a CPO about 2 years ago with 53k. It has 70k now. At the end of the CPO I had them look at the issue. After a few NPFs, they replaced the ignition coils, but not the spark plugs. The spec for plugs is 60k. Seems cheap on their part.

This is normally my wife's car, but I've been driving it lately. I notice with the AC stopped at a light, the RPM went pretty low - near 500. I think the dealer set it super low for the transmission clunk. I bumped that up 100 overall.

Did anyone find an easy fix for this?

[chriscpmtmp]

I did the plugs. Then increased the idle by 100. Not much luck.

It really runs like craps when it is cold. Then decent when it warms up. We literally count to 10 before driving away. Otherwise it like a small boat on rough water - rrrr .... rrrr .... rrrr ...

ouch.

Originally Posted by chriscpmtmp

I read through this post. I think I have similar issues in my 2011 328 xdrive. I notice roughness when it starts, and some weird shifting. I didn't break it down as much as some others. I do think it clunks into reverse if the car is trying to find the idle after a cold start. We usually count to 10, then go. If not, it tends to clunk an pulsate.

I bought it as a CPO about 2 years ago with 53k. It has 70k now. At the end of the CPO I had them look at the issue. After a few NPFs, they replaced the ignition coils, but not the spark plugs. The spec for plugs is 60k. Seems cheap on their part.

This is normally my wife's car, but I've been driving it lately. I notice with the AC stopped at a light, the RPM went pretty low - near 500. I think the dealer set it super low for the transmission clunk. I bumped that up 100 overall.

Did anyone find an easy fix for this?

[fleetfoot]

I had some of the same symptoms as many have described here:
1) random power "hiccups" at lower rpms (around 2-3k) in the first few minutes of driving a couple times each week
2) Uneven power delivery across the entire rev range
3) Rough idle
4) No CEL or engine codes to help with diagnosis
5) 70,000 on the odometer

I began by cleaning my MAF and VANOS solenoids, but they both looked clean and there wasn't any improvement after cleaning.

Next, I tried resetting my adaptive throttle, which also didn't improve things.

I finally started using my Automatic Car Adapter to start reading Short Term Fuel Rates and saw some symptoms indicating an ignition (spark plugs) problem. So I replaced all 6 plugs, which took me about 2 hours. The hardest part was getting the spark plug socket to stay on my socket extension, which I solved by putting a small square of theraband rubber on the end of the extension between it and socket. Then the socket stayed in place.

I just cranked her up and the idle was back to normal. Went for a drive and didn't have any hiccups. The power delivery also felt much smoother. I have the 3-stage intake manifold on my engine, and the transition felt much less abrupt than it had the past few months. It might be placebo effect, but I felt like I was able to shift smoother (manual) because the throttle was working better.

Lessons learned:
1) If you're at 65,000 miles on an N52, think about replacing the spark plugs
2) If you have a 3-stage intake manifold (with a tune), make sure you aren't applying heavy throttle at low rpms just because you have all that new torque at low rpms. I always thought I knew what "lugging" was and that I wasn't doing it, but looking back maybe I was. Apparently lugging can cause premature spark plug failure. So moral of the story is, if you're going to accelerate hard go ahead and downshift so you don't damage your spark plugs.

Hopefully this info is helpful to someone else! Feels good to have my buttery smooth straight 6 back

[Spitfire007]

I just did plugs and coils, at 86000 miles. Solved my hesitation and rough idle issues, granted they were mild to begin with, but the hesitation was getting progressively worse.

[DaanBMW]

did plugs, coils, maf, solenoids, vvt motor, camshaft positioning sensors, vvt check valves. symptoms still there: hesitation/stumbling at starts or low rpms + the rpms drop badly when taken out of gear after coasting, at times killing the engine (with a/c on). puzzled by this beyond belief...

[archuzzi]

Originally Posted by TheAxiom

Thank you, I mean that.

Did you ever find a solution? Having the same issues you have described.

[archuzzi]

Coils and plugs not the issue so I took it to my independent for them to read it even though I wasn't getting any errors. The eccentric shaft sensor sent out 5 codes and was my issue, flooded with oil. Here is a DIY guide:

http://www.e90post.com/forums/showthread.php?t=697252

[gabrielh]

Just to chime in, I had exact same issue than OP on my 2011 Z4 N52 3.0 engine 51k miles so I came across this thread. I replaced the spark plug and cleaned the VANOS Solenoid with brake cleaner and it's been running flawlessly since.

[major330i]

Hey Daan,

did you managed to solve the problem with the hesitation at lower rpm? I have exactly the same problem and also no fault codes stored. Would be nice to hear your status about fixing this.

best regards

Major

Originally Posted by DaanBMW

did plugs, coils, maf, solenoids, vvt motor, camshaft positioning sensors, vvt check valves. symptoms still there: hesitation/stumbling at starts or low rpms + the rpms drop badly when taken out of gear after coasting, at times killing the engine (with a/c on). puzzled by this beyond belief...

[DaanBMW]

Still not solved it. However during the colder season it's a bit better and it gets less noticeable.

List of parts swapped out: spark plugs, coils, maf, solenoids, vvt motor, camshaft positioning sensors, vvt check valves, fuel pump ECU.

Also cleaned throttle body.

Also all my software is the latest possible via INPA.

[DaanBMW]

major330i: Just read your visitor message (seems no notifications for these msgs are received ?).

It's depressing... my really last card was replacing the fuel pump & relay. You listed fuel pump & filter, but not the relay.

No idea about EGR - was not on my list.

I don't have DISA valves mine is the 1 stg intake.

[major330i]

I have an n53.. there is just the disa left over and the egr valve. If you look at the symptoms the problem seems to appear when the car running with open egr valve.
I have Ista+ on my laptop (the original bmw Diagnose Software). When I check the my car there are no fault Codes so I did a couple of test modules. Only The test module „misfire detection“, which is specially developed to analyze misfires caused by coils, Injectors and spark plugs, detected misfires on cylinder 2. in the end of the test module Ista tells me to replace coil spark plug and injector on cylinder 2. the coils and spark plugs are completely new and all Injectors are index 11 and were installed half a year ago + coded. My Plan is to switch injector 2 (misfire cylinder) with another injector and repeat the test module. If the misfire appears on the other cylinder it must be the injector. Without Ista it’s all guesswork especially when there are no fault Codes stored. I will report if I manage to fix this problem.

[DaanBMW]

Originally Posted by major330i

I have an n53.. there is just the disa left over and the egr valve. If you look at the symptoms the problem seems to appear when the car running with open egr valve.
I have Ista+ on my laptop (the original bmw Diagnose Software). When I check the my car there are no fault Codes so I did a couple of test modules. Only The test module „misfire detection“, which is specially developed to analyze misfires caused by coils, Injectors and spark plugs, detected misfires on cylinder 2. in the end of the test module Ista tells me to replace coil spark plug and injector on cylinder 2. the coils and spark plugs are completely new and all Injectors are index 11 and were installed half a year ago + coded. My Plan is to switch injector 2 (misfire cylinder) with another injector and repeat the test module. If the misfire appears on the other cylinder it must be the injector. Without Ista it’s all guesswork especially when there are no fault Codes stored. I will report if I manage to fix this problem.

EGR... like I said I never researched it. Since mine doesn't have DISA it's low probability. What about the fuel relay ? although if you said the fuel filter you likely did the full kit incl. the relay - can you confirm ? (that'd be a good reference point for me) I read about some people installing an extra fuel filter instead of replacing the stock one in the kit.

My strong impression is that the VVT is causing it. The VVT activates only when car is warm, which is when I see the symptoms, not with the car cold (not sure if EGR does the same). I looked at disabling it but so far haven't found a way.

I only have INPA and I don't think it has such test modules, but have to check. I sure hope you get the injector to be the culprit, but from the sounds of it it's not highly likely.

[major330i]

i changed both parts which are under the backseat (the fuel pump, the second part is a filter which also includes the pressure control). Nothing changed! I had the same idea as you -> fuel relay! but.. there is no fuel relay.. the car has an control module for the fuel pump and regulates the fuel pump. So the relay is integrated in this module or there is no need for it. So i changed the control module (sits behind the backseat) and coded it. Nothing changed.

My car has no Valvetronic.. if we have exactly the same issue then the VVT and DISA shouldn't be the problem.
There just 5 options left.
1:air leaks (trottle Body sealing, egr sealing, vacuum hoses)
2.The Egr valve can't close properly (thinking about to deactivate the whole egr system)
3. Injector (because of the test module "misfire detection")
4. Problems with nox Sensor or catalytic converter (i have the secondary cats/ nox cats deleted)
5. Transmission problem (low oil level or bad torque converter)

The egr is closed while cold start. The car has to reach a certain cooling temperature until the egr starts to work. The egr works just in a special rpm range (i think 1000-2000). It could be that the egr can't close properly like it should so there could be a leak where exhaust gases enter the intake.

i read they changed allready your injectors. Which index have your injectors (this is important). Injectors with index under "11" had problems. But if they changed some injectos and replaced them with index "11" then all Injectors have to be index "11". It's not allowed to mix them up.. only if the injectors below index "11" can mixed up. A second point is that they have to be coded after replacing them. So this is also a point to check if ur not sure about it.

[PhaseP]

You two are comparing different engines n52 and n53. N52 doesn’t use EGR, and doesn’t have direct fuel injectors. It uses port injection, low pressure injectors.

[DaanBMW]

I always thought an injector would manifest itself at more than this take-off/low speed hesitation, like issues at idle and/or at higher speeds. So I never tested anything injectors.

I just realized the N53 is direct injected... I would think it's not injector related given mine is port-injected.

And mine being a manual tranny in which I changed the oil 4 times in 40k miles, I doubt it's anything related to tranny.

Excellent to see more info about different attempts to solve this. I for one I'm still stumped...

[W37V]

Originally Posted by DaanBMW

I always thought an injector would manifest itself at more than this take-off/low speed hesitation, like issues at idle and/or at higher speeds. So I never tested anything injectors.

I just realized the N53 is direct injected... I would think it's not injector related given mine is port-injected.

And mine being a manual tranny in which I changed the oil 4 times in 40k miles, I doubt it's anything related to tranny.

Excellent to see more info about different attempts to solve this. I for one I'm still stumped...

Silly question, but have you done a smoke test to see if you have any vacuum leaks? Vacuum leaks can lead to bad idle etc.

I didn’t bother to read it all, but have you tried swapping MAF and clean your throttle body?

[major330i]

I have already changed the maf sensor and cleaned the throttle body and changed the sealing. The hesitation is still there. No smoke test done yet. That’s a good idea.
There are not many things left which can cause hesitation.
Disa, Injector, Agr valve, air leak.. but no fault Codes ?

[DaanBMW]

No smoke test either. MAF was cleaned and later replaced with brand new. And i've no other problems on idle or codes. Air/fuel leaks would cause more misbehaving.

The hesitation is there upon start-up or accelerating from low rpms, and also when coasting in gear and then taking it out of gear - the rpms drop so suddenly that if a/c is on at times if can kill the engine (w/o a/c it usually recovers to idle speed). scary if you're right in the middle of a turn and lose power steering, happened multiple times.

[W37V]

Originally Posted by DaanBMW

No smoke test either. MAF was cleaned and later replaced with brand new. And i've no other problems on idle or codes. Air/fuel leaks would cause more misbehaving.

The hesitation is there upon start-up or accelerating from low rpms, and also when coasting in gear and then taking it out of gear - the rpms drop so suddenly that if a/c is on at times if can kill the engine (w/o a/c it usually recovers to idle speed). scary if you're right in the middle of a turn and lose power steering, happened multiple times.

Your symptoms sound very similar to (i think) another person who had similar issues after installing his supercharger. It ended up being something weird. I think it was faulty throttle body. When I’m on the computer, I’ll try to find the post. In the meantime look for keywords supercharger, idle, hesitation, intersection.

I think this is the one: http://www.e90post.com/forums/showthread.php?t=1300719

[DaanBMW]

Originally Posted by W37V

Your symptoms sound very similar to (i think) another person who had similar issues after installing his supercharger. It ended up being something weird. I think it was faulty throttle body. When I’m on the computer, I’ll try to find the post. In the meantime look for keywords supercharger, idle, hesitation, intersection.

I think this is the one: http://www.e90post.com/forums/showthread.php?t=1300719

I suspected the throttle body a while ago. So I removed it, and it looked reasonably clean, with the mechanism operating freely by hand. I also cleaned it up a bit.

Not aware of any other tests that I can do. Also AFAIK the TB is actually only used as a backup to the VVT, and with not codes whatsoever I don't think the VVT has any system-identified issues and thus the TB should not really do much.

What this backup really means is not clear to me. I know my TDI was using the throttle body only when the engine was shut down to make it smoother (less shudder).