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The BMW Doctor
The BMW Doctor, BMW Technician
Category: BMW
Satisfied Customers: 2429
Experience:  Over 30 years experience, 13 years with BMW, former BMW Shop Foreman, Service Manager
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I have been working on my bmw 316ti compact, e46, n42 engine

Customer Question

I have been working on my bmw 316ti compact, e46, n42 engine for weeks now. The problem started after an oil & filter change, and last two spark plugs. I have however eliminated any coil or spark plug problems, and I am leaning towards either low oil pressure (oil level ok), faulty eccentric shaft, or faulty vvt gear servomotor acutator.
The car has clicking noises at the top, sounds like the intake manifold (possible pcv ?), and sounds terible at the bottom of the engine, especially when high revs, sounds like lack of oil.
Most times you press the accelerator and the car suffocates and stalls. You can-not drive it as it will just die when you press for more power.
The fault codes are 2782 Cam Outlet Sencor and after running for 1 min also 27BB cam control outlet vanos. I have replaced all plugs, fuel, air oil filter, oil change, MAS sencor, Air Diff Pressure Sencor. I am an electrician, and have tested wiring to camshaft sencor and replaced the sencor twice, and swapped with the inlet sencor, and still get this fault.
Submitted: 5 years ago.
Category: BMW
Expert:  JacobTD replied 5 years ago.
Welcom to Just Answer
You are correct about the low oil pressure. If there is a bad nocking sound in the lower part of the engine this would be the MAIN bearing/s are bad. becasue of this bad bearing/s and becasue its at the bottom of the engine " begaining oil system" you are lacking enough oil pressure to move the advance the cams while accelerating. The VANOS system is ran off the actuall engine oil pressure. of corse the control of these is Electronic however. This of corse needs to be confirmed by doing an oil pressure test at the top of the engine.
These did have vanos issues with the tensioners breaking resulting in the cams not moving the way they should and getting stuck. To fix this problem it REQUIRES a VANOS adjuting tool set. and they are spendy. Search DR VANOS for seals and parts.
Customer: replied 5 years ago.
Hi there, as much as your answer seems to verify a few things, not sure if I also said about the loud tapping noise, which is constant and sounds more like its cominf from the intake maifold (and not the cylinder head ?) maybe pcv knocking or getting stuck ?. Also had no problems or noises etc until the last two spark plugs were changed and the oil filter was changed. Seems strange that a bearing failed after doing this work and had no problems before hand, car was running fine.
Does the camshaft sencor not sending a signal back also stop the vvt servomotor accutator operating. Its strange, as when I measure voltage to this device, it measures 8 volts when unpluged, and then 0volts when plugged back in, but computer is not signaling a fault of short circuit for this motor ?. Also what does the actual fault code 27bb cam control outlet actually mean, is the vanos the actual cam control or other electricsl device.
Sorry but been banging my head against the wall and trying everything, just need a bit more detail and explanation. thanks
Expert:  JacobTD replied 5 years ago.
The Vanos is light a big plunger that when the oil pressure rises with engine speed the Vanos further engages, However, This actuall function is controled by the computer with a simple selinoid that alows the oil pressure to flow to vanos.
If a noise had happened after plugs, you need to remove them and inspect. Could you possibly do a vacuume test on the intake and let me know the results.
Also unhook maf sensor connector and start.. It should die right away
Please if possible snap a pic of engine and attach, if possible try and label the pic where the sounds are coming from.
Customer: replied 5 years ago.
Hi there
Thanks for reply. Have removed all plugs and checked condition and sparks and colour ok. No chance of anything entering head through holes when they was removed, was most careful. Also not a misfire as such, as if I remove one coil pack from each plug in turn, noticeable change in engine noise/revs. so they all appear ok.
Ill send some pics over for you. The sound is more like metalic pop, like popcorn inside the intake manifold, not an actual metal/metal grind or knock ?.
I don't have anything to measure then intake air pressure, but have check for all obvious signs of leakage, and even blew the pipe from the petrol filter to the intake air box out with compressed air before refitting.
I am using BMW INPA software for fault codes etc, is there anything on the digital or analouge readouts that would be useful info for you ?.
The car does die when the maf is unplugged, and I have also recently replaced this MAF sensor.
Can you also explain if the servomotor vvt acutator, that sits on the cylinder head, between the spark plugs, should have power to it, should it be constant whilst engine running, should it be greater than 8 volts, or is this not operating because of the camshaft sensor sending back no signal. Is this is a possible cause, as it may of been disturbed.
I also need to know exactly what fault code 27bb refers to, where is the sensor or electric control for this that tells the VDO or ECU that there is a problem. How does the engine know that the mechanical vanos is not working, is this through the camshaft and eccentric shaft sencors ?.
Will get pics over to you in one hour.
Thanks for your paitence
Expert:  The BMW Doctor replied 5 years ago.
Hello Steve,

This is Jake another Expert here at JA. Your Expert has "opted out" and will no longer be working with you. I will do my best to assist you.

In reading over your question I believe there may be a simpler answer to this problem than you suspect. It can be very difficult diagnosing engine management issues with modern day vehicles, let alone answering diagnostic questions on vehicles that we can not physically inspect and must rely solely on the information provided by the customer. It is also easy to assume that these management systems are so complicated that the problem must be complicated.

This does very much sound like an oil pressure issue. I believe the noise in the intake to be related to the improperly timed camshaft and the activation of the intake valves of the hydraulic lifters (also oil pressure controlled). Based on the fact that the vehicle ran normally until the oil filter was changed, there is a high probability that the oil filter is either incorrect or failed. I STRONGLY SUGGEST YOU ASSURE THAT IT IS THE CORRECT OIL FILTER AND CHANGE IT TO MAKE SURE IT IS NOT A FAILED NEW FILTER.


Please let me know the results of the oil filter change and the oil pressure if it does not correct the condition.

I hope I have answered your questions and addressed your concerns. Should you have further questions on this matter, please do not hesitate to ask. I want you to be 100% satisfied with my answer.

Positive feedback, referrals and bonuses are always APPRECIATED. If you accept my answer, please don’t forget to leave feedback.

Thank You!
Jake “The BMW Doctor”
Customer: replied 5 years ago.
Hi Jake,
Thanks for your detailed answer, and being an Electrical Engineer, I appreciate the difficulty in diagnosing something over the net without having it with you.
I too had the assumption about the oil filter, so not having another to hand, removed it for 10 mins to see if this was causing any problems or any blockages, didnt change anything.
I keep asking about the voltage to the VVT GEAR SERVOMOTOR/ACUTATOR, as this is right near the spark plugs that I changed, I also know this controls the cam or valve movement, so wondered what voltage I should be getting to this ?.
I also ask, as when I remove the plug from it I get no extra fault codes, so wondered if this was the fault 27bb cam control outlet-vanos, that keeps coming up on INPA software.
Would it do any damage to remove the oil filter tempoarily, as its brand new oil in the system.
Also forgot to mention that the plastic end of the dip stick is missing, so is hard to check the oil level.
However when doing oil change, sure I read 4.55 litres max, which is what I put in, 5w/30 fully synthetic. I have no low oil level light illuminated, and I have no oil pressure fault codes, does this still mean there could be an oil circulation problem ?.
Where is the oil pump on these, and are they belt driven or electric.
I hope im not the only one who asks one million questions, but you are coming up with the same things I am, but not being a qualified mechanic, and never worked with these vanos units before need to ask a lot of questions to narrow down the problem. Also sprayed eccentric shaft sencor with contact cleaner when servicing ?. When I remove this plug now it does give me fault codes 2852 VVT REF SENSOR and 2850 VVT GUIDING SENCOR, which make no difference to the engine when the car is running, and also the codes do not re-occur when plugged back in, which tells me that this is not the problem either ?.
Expert:  The BMW Doctor replied 5 years ago.
I am sorry I do not have the answers to the questions you ask me. If I can not help you I will opt out so that someone else can help you. Let me get back to the basic question of my concern.

How can you "not having another to hand, removed it for 10 mins to see if this was causing any problems or any blockages, didnt change anything."? I do not understand. How can you run the engine without an oil filter? If you don't have or can't get a new filter, do you have the old oil filter to put back on and try?

I also do not understand this question "Would it do any damage to remove the oil filter tempoarily, as its brand new oil in the system?" How can you run the engine without an oil filter?

You need to get another or the old oil filter on it to eliminate that possibility before proceeding with other possibilities.

The oil pump is mechanical and inside the engine in the oil sump.

Thank You!
Customer: replied 5 years ago.
Hi there,
The oil filter is of the paper cartridge type that goes inside a housing, not the standard all in one with the female thread, that you couldn't start the engine without ?.
So I removed the paper cartridge and put the lid back on the housing, in-case there was a problem with this.
If the oil pump is mechanical, how is it driven (Drive belt ??), and I assume it has a sensor. Also would a oil pressure warning code or light illuminate if there was an oil pressure issue.
Expert:  The BMW Doctor replied 5 years ago.
OK, Are you sure that something isn't stuck in the housing? Maybe a piece of paper or something?

Customer: replied 5 years ago.
No, have checked all holes etc unless something was blocking the holes ?
Expert:  The BMW Doctor replied 5 years ago.
Well, If it were me... I don't believe in coincidences. At least not unless I have eliminated everything else, I could have effected. If you are not DEAD SURE, I would do everything necessary to check into it. If you have looked real good with a mirror or removed and inspected it, I would test the oil pressure with a mechanical gauge. In my opinion based on the turn of events I would want to be dead sure of the oil pressure. The warnings are no longer simply a switch that grounds when the pressure falls below a certain pressure and provides a ground for a bulb. It goes through a processor that illuminates the light and warning gong. What if the system is not working?

Let me know if you have any more questions.

Customer: replied 5 years ago.
Would it pay me to remove the oil filter housing to inspect. I have no methods of testing oil pressure with mechanical guage, is there anything on my inpa software that can verify this ?
Expert:  The BMW Doctor replied 5 years ago.
that would be one method to check for restriction in the housing, but it still does not check the oil pressure. There is no way to check the oil pressure with the inpa.

This may be a case when your in a bit over your head. Based on your statements it really does sound like an oil pressure issue, but I can't be sure because I can't personnaly inspect the vehicle. I have to base my opinion an your statements alone. Your symptoms are not consistent with any "pattern failures" typically come across when the vehicle fails on it's own. Since it manifested only after you replaced the last two spark plugs and the oil & filter, I have to suspect that the most likely cause (again based ONLY on your statements) is that somehow the oil pressure has somehow been altered. That is the most likely cause that "fits" and I can think of. I believe the next step it an oil pressure test to verify the oil pressure as been effected. If you have other methods to do so, that is a decision that you will need to make. Once you have exhausted any possibilities that you have th ability to investigate, if you have not found the cause I suggest you take it to a qualified BMW shop to Test, Diagnose, and Repair the condition. It may not have anything to do with the oil pressure at all. Maybe they will see something when they inspect it, and identify and repair the cause.

Thank you!
Customer: replied 5 years ago.
Sorry for the delay.
Im afraid im not satisfied with the answers I received, as none of these are the problem.
Whilst I appreciate not being able to diagnose properly without being with the car, I did not receive direct answers to direct questions, especially those regarding fault codes and other issues.
I was passed onto 3 people, because others did not know the problem.
so Im afraid I will have to rate the service as poor, as I would of thought a problem having say 20 possible answers, I as a professional electrician would of given all the 20 possible answers, to enable my customer to eliminate all of them.
My car still fails to run.
So I am not prepared to pay two people, especially the first person who wants to charge me £25 and passed it onto someone else. You were the third expert I spoke too.
I have £18 credit in my account, and think it is more than fair to pay this, giving that I am no better off, and still without my car.
Should you have the time to look over my case again, and be decent enough to answer my direct questions, I would be prepared to pay your full fee, but I refuse to pay the first and second experts, who just dismissed it and passed it down to you.
Im sorry, but I wouldn't charge you for something that I couldn't solve or at least lead you in the right direction.
Expert:  The BMW Doctor replied 5 years ago.
Not a problem. As I told you I do not know the answers to your other questions. I think pursuing these questions is "barking up the wrong tree". I think this is likely something you effected when you worked on the vehicle.

I do not think you "paid" anybody unless you "accepted" an answer. Here at JA we do not "charge" anybody for our assistance. When you open a question, the fee for an accepted answer is based on your urgency, detail etcetera. When our experts see your question there is a monetary value associated with the question. We receive no compensation unless you "accept" one of our answers.

I will "Opt Out". I hope that you get this matter resolved. If you would let me know the cause when you find out what is wrong I would very much appreciate it. Also if you find out that is was an oil pressure issue, then I would appreciate it if you would change my feedback and "accept" one of my answers. You will be charged the full question amount anytime you accept an answer. Experts DO NOT send out any payment requests. This is solely the function of "Just Answer" and "".

Sorry I was not able to help you. I gave it my best shot. Hope you get it resolved soon.

Thank You!
Customer: replied 5 years ago.
Hi there
Thanks for your reply, and I appreciate your comments.
Today Im going to remove the top head to see exactly what is going on inside, and see if anything I can do before I take it to the mechanics.
Being recently unemployed, funds are non-existent which is why I have had to have a go. I had one mechanic come, and he just said replace the outlet camshaft sensor, which I have done twice, and charged me £40 for not even looking any further, so you can see why it is frustrating. I am now also getting a new fault code 285a - VVT ACUTATOR MONITORING before running the engine, and when I run it at idle for a couple of mins, get a new code 2866 VVT STOPS LEANING NECASSARY (ADAPTION NEEDED). I also still get the old codes of 2782 - Cam Sensor Outlet & Cam Control Outlet - Vanos.
Have put 12 Volts to both Vanos soleniods, which work, and have got 12 volts at there terminals when the car is running, and even swapped them round.
My assumption at the moment is a faulty or jammed VVT ACCUTATOR MOTOR, which is preventing the movement of the Eccentric Shaft, which in turn has the outlet cam at an angle where the camshaft sensor is not getting the correct reading back to make the adjustments. Therefore the valves are either open or closed to much. No way an expert, but does that sound probable. Or a problem with Vanos or oil supply to it ??
What do you think ?
Expert:  Walt-Mod replied 5 years ago.
I’m a moderator for this topic. Your Professional has opted out and I wonder whether you’re still waiting for an answer. If you are, please let me know and I will do my best to find another Professional to assist you right away. If not, feel free to let me know and I will cancel this question for you. Thank you!
Customer: replied 5 years ago.
Hi there
No, with all due respect, no-one seems to be able to diagnose my problem. So I require no further assistance and wish to cancel this question. Thanks everyone for there help.