[niksss]

Hello guys. I have a problem with my 2012 BMW E92 328i X-Drive (has 61 000 miles). The car has vribrations at IDLE. The vribrations are not serious, but I can feel them in the car and when touching the steering wheel. The vibrations appear only when the car is warm and is idling. When cold or when revved up there are no vibrations at all. There are definitely no missfires and the engine is running on all cylinders. I can feel the vibrations less when the car is on P or N, but they are still present. Also the RPMs move from time to time when idling, but it is not always and I don't think it is related.

I have replaced all coils and relearned valvetronic positions but there was no change. Spark plugs have been replaced 25 000 miles ago. Any ideas what should I do next ? I am thinking about cleaning the vanos solenoids and the MAF sensor. I have Ista D, so if anyone has an idea where can I find some info about my problem in ista would be good. I will attach an image with my error codes, but they are not related I think.

Also I noticed a small oil leak from the Valvetronic motor gasket, but I don't think it is related. I am running a K&N filter and a charcoal delete if that matters.

[niksss]

Cleaned the valvetronic solenoids today. The car still has slight vibrations.

[Eagle1oh7]

Have you had the recall performed for the PCV? That can cause a rough idle.

[niksss]

Originally Posted by Eagle1oh7

Have you had the recall performed for the PCV? That can cause a rough idle.

When I check for recall with my vin it says that there are 0 recalls for my vehicle. I have performed only the recall for the driver airbag.

[rothwem]

It sounds like a vacuum leak. I have the same problem, it's just really tough to trace them without a smoke machine.

[Eagle1oh7]

Have you done any intake mods? You could have a leak around the MAF.

[niksss]

Originally Posted by Eagle1oh7

Have you done any intake mods? You could have a leak around the MAF.

Only charcoal delete and K&N filter. Nothing that could do a leak. The vibrations are like low frequency bass.

[desertman123]

Check your DISA valves ,I was chasing this for like a year before I found one of my DISAs were slow to actuate

[niksss]

Originally Posted by desertman123

Check your DISA valves ,I was chasing this for like a year before I found one of my DISAs were slow to actuate

If there is a problem with the disa wound't there be a code for the disa ?

[desertman123]

Originally Posted by niksss

If there is a problem with the disa wound't there be a code for the disa ?

It SHOULD throw a shadow code, but I didn't get a code for my big DISA ever, only my small one.

[niksss]

Also I forgot to mention that my fuel consumption has increased. Highway I managed before 23.5MPG, and now my fuel consumption is around 18MPG with the same driving speed (around 90MPH). What is the normal average consumption for this speed ?

[niksss]

Today my car had a hard cold start. The RPMs were jumping up and down from 1000 to 2000 and the car was having a hard time. After 20 seconds the car ran like before. The CEL came on. I run a diagnosis and the codes that appeared at this time were: 2C2B, 2C2C, 2C31, 2C6B, 2CB6.
2C2B - Oxygen sensor before cat: System check
2C2C - Oxygen sensor 2 before cat: System check
2C6B - Oxygen sensor after cat: System check
2CB6- Oxygen sensor after cat: Signal fixed at lean
2C31 - Oxygen sensor emissions control

Any Idea what would cause all oxygen sensors to mess up like this ? I have replaced Oxygen sensor 2 before cat, before about 6000 miles. I don't think all of them should go out at the same time at this mileage ?

[rothwem]

A lean condition could be caused by a vacuum leak. Have you had someone do a smoke test yet? Vibration that doesn't go away in P or N and a lean code would indicate that un-metered air is entering the combustion chamber. The reason your car smooths out when you're not at idle is because its taking in more air and the small amount of un-metered air isn't as significant.

Anyways, I have the same issues are you, minus the codes, but including the poor fuel mileage. I had a smoke test done and I'm leaking from the CCV tube under the intake manifold. The mechanic also noted that my passenger engine mount was leaking.

I'm going to do the work this weekend and I'll let you know if it fixes the problem.

[niksss]

Originally Posted by rothwem

A lean condition could be caused by a vacuum leak. Have you had someone do a smoke test yet? Vibration that doesn't go away in P or N and a lean code would indicate that un-metered air is entering the combustion chamber. The reason your car smooths out when you're not at idle is because its taking in more air and the small amount of un-metered air isn't as significant.

Anyways, I have the same issues are you, minus the codes, but including the poor fuel mileage. I had a smoke test done and I'm leaking from the CCV tube under the intake manifold. The mechanic also noted that my passenger engine mount was leaking.

I'm going to do the work this weekend and I'll let you know if it fixes the problem.

I haven't done a smoke test. I will try to do one myself using a vape. I will be waiting for the results after your repair.

[rothwem]

Originally Posted by niksss

I haven't done a smoke test. I will try to do one myself using a vape. I will be waiting for the results after your repair.

Ha! Idle vibrations are gone. I pulled the intake manifold and replaced the CCV hose, turned out it was cracked between the two IM connections.

Now to address my cracked radiator...

[niksss]

Originally Posted by rothwem

Ha! Idle vibrations are gone. I pulled the intake manifold and replaced the CCV hose, turned out it was cracked between the two IM connections.

Now to address my cracked radiator...

Nice. I think I have a vacuum leak, so I will check the same thing. Is the manifold hard to remove ?

[Rmtt]

Originally Posted by niksss

Nice. I think I have a vacuum leak, so I will check the same thing. Is the manifold hard to remove ?

Not really. But have a look at YouTube for people replacing their starters and most will show you detailed instructions on how it comes out.

Ironically....it's these CCV hoses that are cracked when swapping over to a 3SI intake, or removing the Valve Cover.

I was lucky when doing both jobs on mine. But they are a PITA to disconnect and become brittle overtime. I had new ones on hand just in case mine were to crack. You will also want to buy intake gaskets and a throttle body gasket as well. They are cheap enough anyways.

[rothwem]

Originally Posted by Rmtt

Not really. But have a look at YouTube for people replacing their starters and most will show you detailed instructions on how it comes out.

Ironically....it's these CCV hoses that are cracked when swapping over to a 3SI intake, or removing the Valve Cover.

I was lucky when doing both jobs on mine. But they are a PITA to disconnect and become brittle overtime. I had new ones on hand just in case mine were to crack. You will also want to buy intake gaskets and a throttle body gasket as well. They are cheap enough anyways.

It was kind of a pain due to the amount of things you have to disconnect to get it out. The CCV hose connection at the back of the valve cover near the firewall was a motherfucker, and the throttle body connector broke off in my hand when I tried to take it off.

[faviles]

Please listen to what everyone else is saying and get a smoke test done. I have a 2007 328xi N51 which had about the same symptoms you had and I tried doing a smoke test on my own which didn't show me anything. I was using an old fog machine my dad had laying around.

I gave up and took it to a mechanic to have it diagnose, they hooked up their fancy Snap On smoke tester and almost immediately smoke poured out of my crankshaft seal. My point being, do not waste much time in doing things yourself and wasting money replacing things, I paid 80 bucks for my smoke test to be done. My car no longer shakes and my CEL hasn't been on in over 200 miles driven.

[niksss]

Originally Posted by faviles

Please listen to what everyone else is saying and get a smoke test done. I have a 2007 328xi N51 which had about the same symptoms you had and I tried doing a smoke test on my own which didn't show me anything. I was using an old fog machine my dad had laying around.

I gave up and took it to a mechanic to have it diagnose, they hooked up their fancy Snap On smoke tester and almost immediately smoke poured out of my crankshaft seal. My point being, do not waste much time in doing things yourself and wasting money replacing things, I paid 80 bucks for my smoke test to be done. My car no longer shakes and my CEL hasn't been on in over 200 miles driven.

Today I did a smoke test. There was no leak anywhere. The guys at the shop did a o2 sensors test by monitoring them and spraying some fuel in the intake. The o2 sensors responded well, but the long term fuel trims have a very large differance. The mechanic told me that he has no idea why, but he told me that the catalyst might be bad. I am kind of skeptical because the low mileage of the car. I will attach a photo with the fuel trims if anyone has an idea on what could cause the large difference in long term fuel trim. What are the normal values of the fuel trim ? I guess around 0 ?

Also the mechanic told me that one of my post cat sensor was slow to heat up and reacts slower than the other. Could this cause rough idle and increased fuel consumption ? I think the post cat sensors are only for emissions ?

View post on imgur.com

Update: After more research, I found that the LTFT in bank 1 is a lot higher. When idling I have around 11% positive LTFT on Bank1 and aroud 0% LTFT on bank 2. When cruising with 60mph the LTFT drops to 6-7% on bank1 and stays around 0-1% on bank2. When decelerating the LTFT jumps to 14% on bank1 and stays around 0 to -3% on bank2. Under hard acceleration the LTFT on bank1 goes from -4 to +4% and bank2 stays at 0%. The image that I add under is the LTFT on idle.

What could cause only one bank to run lean ? The difference between the two banks is very big in my opinion. Rule out injectors because I can run the car on two types of fuel (Gasoline and LPG). And the fuel trim is absolutely the same om both fuels (they have separate injectors). Any ideas ?

View post on imgur.com

[niksss]

Hello guys. I fixed the problem one week ago. I replaced Bank 1 Sensor 2. It was the original sensor of the car. Thought it was a bit soon to fail at 110 000km. The check engine light is now gone and the fuel consumption is way better. Also the problems I was having with idling are all gone. All of the mechanics told me that post-cat sensors don't have impact on fuel injection. I guess they are all wrong.