E92 M3 - Metallic clunk / grind on cold start (With 3 Videos + Image of Noise)

[SenorFunkyPants]

Originally Posted by FormulaMMM

Ok. And theories from anyone as to why these would only make noise on startup?

This from the "SIEMENS MS 42.0 ENGINE CONTROL SYSTEM" manual for a E46 M3 which has a high pressure VANOS system.
http://www.beisansystems.com/misc/SE...ROL_SYSTEM.pdf

"When the engine is started, the camshafts are in the “fail-safe” position (deactivated). The
intake camshaft is in the RETARDED position - held by oil pressure from the sprung open
solenoid. The exhaust camshaft is in the ADVANCED position - held by a preload spring in
the actuator and oil pressure from the sprung open solenoid.
After 50 RPM (2-5 seconds) from engine start, the ECM is monitoring the exact camshaft
position.
The ECM positions the camshafts based on engine RPM and the throttle position signal.
From that point the camshaft timing will be varied based on intake air and coolant temperatures.
The double VANOS system is “fully variable”. When the ECM detects the camshafts are in
the optimum positions, the solenoids are modulated (approximately 100-220 Hz) maintaining
oil pressure on both sides of the actuators to hold the camshaft timing."


Again this is for the VANOS on an E46 M3 (can't find the same document for the E9x) but if the startup system is similar for the E9x M3 then the cycle goes:
VANOS is in default (fail safe) position
start engine
wait 2 secs
ECU checks VANOS positions
ECU makes some adjustment to VANOS and the clacking noise occurs.

The adjustments are based on throttle position, RPMS, air and coolant temps". As the clacking only occurs when the engine has been left standing then perhaps its a cold coolant temp that initiates the noise rather than a loss of oil pressure in the VANOS system.....on affected cars.

[anom3]

...wow.

my 2 (yes, i ordered 2 on purpose) stethoscopes are due to come in today in about 4 hours. ill put one on the left, one on the right (ear and vanos) and see where the noise is more pronounced.

this combined with the report from another member stating that BMWNA had them replace his vanos and the noise went away (and has stayed away, 30k miles) is the clearest indication i have seen so far as to the cause of this.

the only other 'we fixed it this way' was a report by someone (by the looks of it, they were bmw technicians by trade) stating they changed the check valves and that cured the issue. but i have done that, and it has not solved the problem. worth noting the post states they repaired 2 vehicles by replacing the check valves. even tho i had them done, what always had me wondering is the fact that there is a distinct pause between ignition -> noise. once again, no expert here, but if it was caused by a lack of oil due to bleeding down, one would think it would happen right away.

THANK YOU. i will keep everyone posted. my only issue with doing this is i would really rather not do BOTH sides (unless need be) as the cost... well.. doubles so i'm going to do my best to narrow it down to 1-4 or 5-8.

THANKS!

Originally Posted by SenorFunkyPants

This from the "SIEMENS MS 42.0 ENGINE CONTROL SYSTEM" manual for a E46 M3 which has a high pressure VANOS system.
http://www.beisansystems.com/misc/SE...ROL_SYSTEM.pdf

"When the engine is started, the camshafts are in the “fail-safe” position (deactivated). The
intake camshaft is in the RETARDED position - held by oil pressure from the sprung open
solenoid. The exhaust camshaft is in the ADVANCED position - held by a preload spring in
the actuator and oil pressure from the sprung open solenoid.
After 50 RPM (2-5 seconds) from engine start, the ECM is monitoring the exact camshaft
position.
The ECM positions the camshafts based on engine RPM and the throttle position signal.
From that point the camshaft timing will be varied based on intake air and coolant temperatures.
The double VANOS system is “fully variable”. When the ECM detects the camshafts are in
the optimum positions, the solenoids are modulated (approximately 100-220 Hz) maintaining
oil pressure on both sides of the actuators to hold the camshaft timing."


Again this is for the VANOS on an E46 M3 (can't find the same document for the E9x) but if the startup system is similar for the E9x M3 then the cycle goes:
VANOS is in default (fail safe) position
start engine
wait 2 secs
ECU checks VANOS positions
ECU makes some adjustment to VANOS and the clacking noise occurs.

The adjustments are based on throttle position, RPMS, air and coolant temps". As the clacking only occurs when the engine has been left standing then perhaps its a cold coolant temp that initiates the noise rather than a loss of oil pressure in the VANOS system.....on affected cars.

[anom3]

quick question:

i recall reading quite a few times something along the lines that if one were to disconnect the vanos solenoids, it forces the cams into 'base' mode and disables the vanos (in all honesty, i dont even know what that means...)... does this sound correct? i'm thinking about disconnecting my vanos solenoids and seeing if the noise is present... bad idea? good idea?

Originally Posted by SenorFunkyPants

This from the "SIEMENS MS 42.0 ENGINE CONTROL SYSTEM" manual for a E46 M3 which has a high pressure VANOS system.
http://www.beisansystems.com/misc/SE...ROL_SYSTEM.pdf

"When the engine is started, the camshafts are in the “fail-safe” position (deactivated). The
intake camshaft is in the RETARDED position - held by oil pressure from the sprung open
solenoid. The exhaust camshaft is in the ADVANCED position - held by a preload spring in
the actuator and oil pressure from the sprung open solenoid.
After 50 RPM (2-5 seconds) from engine start, the ECM is monitoring the exact camshaft
position.
The ECM positions the camshafts based on engine RPM and the throttle position signal.
From that point the camshaft timing will be varied based on intake air and coolant temperatures.
The double VANOS system is “fully variable”. When the ECM detects the camshafts are in
the optimum positions, the solenoids are modulated (approximately 100-220 Hz) maintaining
oil pressure on both sides of the actuators to hold the camshaft timing."


Again this is for the VANOS on an E46 M3 (can't find the same document for the E9x) but if the startup system is similar for the E9x M3 then the cycle goes:
VANOS is in default (fail safe) position
start engine
wait 2 secs
ECU checks VANOS positions
ECU makes some adjustment to VANOS and the clacking noise occurs.

The adjustments are based on throttle position, RPMS, air and coolant temps". As the clacking only occurs when the engine has been left standing then perhaps its a cold coolant temp that initiates the noise rather than a loss of oil pressure in the VANOS system.....on affected cars.

[SenorFunkyPants]

Originally Posted by anom3

quick question:

i recall reading quite a few times something along the lines that if one were to disconnect the vanos solenoids, it forces the cams into 'base' mode and disables the vanos (in all honesty, i dont even know what that means...)... does this sound correct? i'm thinking about disconnecting my vanos solenoids and seeing if the noise is present... bad idea? good idea?

I couldn't say...you could try messaging "Regular Guy", he may have a better understanding of the VANOS than I do.

[anom3]

so, by the looks of it my mechanics are solid...:

i went in there with vanos part numbers in hand, played the clips to them etc etc etc...

they suggested i hold off, and let the car sit there over night and they will hoist it up on their jack today, and have 3-4 people listen to it from bottom AND top to try and pinpoint the source of the noise tomorrow morning.

they said its MOST likely the starter. here is what they said they have seen before:

the shavings from the clutch get picked up by the flywheel and end up gumming up the starter solenoid / starter making the 'pull back' more difficult. they also said that just because there is a 'pause' between ignition and the noise, doesnt mean the starter has stopped. the point in time where the starter solenoid pulls back the starter gear is actually AFTER the motor has ignited. the situations they had delt with when there was these clutch shavings all that needed to be done is a good cleanup (did not mention if tranny was removed to access flywheel) and a new starter solenoid.

they will know for sure if its the starter or not tomorrow as they will have one man on the starter with a stethoscope.

worth mentioning : he said knew quite a bit about the vanos, and in the e92 the vanos is actually a very simple unit. its just 2 pieces that sit together. he also said the whole process is controlled by the vanos solenoids on the e92. that by raising / lowering oil pressure they control the vanos.

also he said that if its not the starter he is leaning more towards something related to oil pressure rather then vanos. he also said if there was an issue with the vanos, chances are quite high i would be able to hear it not just on cold start.

he didnt rule out the possiblity of it being the vanos, but said it well worth checking a number of other things first before making any rash expensive repairs.

he also mentioned that whenever its a vanos issue, there is quite a diistinct sound to it. and this is much more metalic then the issues they see with vanoses.

worth mentioning, i have quite a bit of faith in their technical abilities. as i was leaving, another m3 e92 pulled up to get work done. they also had some sort of V10 (im not too knowledable on the bmw motors...) bmw motor being rebuilt right in front of me.

last but not least:

they will do (are doing now actually) the last of the 4 check valves. so that will all be done tomorrow.

also, they will replace the both chain tensioners as its about 150-200 bucks for both parts, and the labor will be free as they have to get in there to change the last check valve anyways. so i said why not, just do it. fyi for those who dont know, the drivers side chain tensioner is super easy to get to, its right there at the front of the drivers side valve cover. the passenger side is the difficult one, same with the check valve... that's why they didn't have time to do this last time i had the car there (a week or so ago).

also, all the diganostics etc etc are free. mind you i have dumped quite a bit of dough there and they are my go to guys with pretty much anything i dont want to tackle on my own.

by polish standards, they are on the expensive side. still quite a bit cheaper then those in more western countries (uk / germany / etc) or the us im sure. then again any gains there are offset by our (wtf, arnt we like 500km from the mothership?!) more expensive parts prices

[///M Power-Belgium]

Originally Posted by anom3

so, by the looks of it my mechanics are solid...:

i went in there with vanos part numbers in hand, played the clips to them etc etc etc...

they suggested i hold off, and let the car sit there over night and they will hoist it up on their jack today, and have 3-4 people listen to it from bottom AND top to try and pinpoint the source of the noise tomorrow morning.

they said its MOST likely the starter. here is what they said they have seen before:

the shavings from the clutch get picked up by the flywheel and end up gumming up the starter solenoid / starter making the 'pull back' more difficult. they also said that just because there is a 'pause' between ignition and the noise, doesnt mean the starter has stopped. the point in time where the starter solenoid pulls back the starter gear is actually AFTER the motor has ignited. the situations they had delt with when there was these clutch shavings all that needed to be done is a good cleanup (did not mention if tranny was removed to access flywheel) and a new starter solenoid.

they will know for sure if its the starter or not tomorrow as they will have one man on the starter with a stethoscope.

worth mentioning : he said knew quite a bit about the vanos, and in the e92 the vanos is actually a very simple unit. its just 2 pieces that sit together. he also said the whole process is controlled by the vanos solenoids on the e92. that by raising / lowering oil pressure they control the vanos.

also he said that if its not the starter he is leaning more towards something related to oil pressure rather then vanos. he also said if there was an issue with the vanos, chances are quite high i would be able to hear it not just on cold start.

he didnt rule out the possiblity of it being the vanos, but said it well worth checking a number of other things first before making any rash expensive repairs.

he also mentioned that whenever its a vanos issue, there is quite a diistinct sound to it. and this is much more metalic then the issues they see with vanoses.

worth mentioning, i have quite a bit of faith in the technical abilities. as i was leaving, another m3 e92 pulled up. they also had some sort of V10 (im not too knowledable on the bmw motors...) bmw motor being rebuilt right in front of me.

last but not least:

they will do (are doing now actually) the last of the 4 check valves. so that will all be done tomorrow.

also, they will replace the both chain tensioners as its about 150-200 bucks for both parts, and the labor will be free as they have to get in there to change the last check valve anyways. so i said why not, just do it.

also, all the diganostics etc etc are free. mind you i have dumped quite a bit of dough there and they are my go to guys with pretty much anything i dont want to tackle on my own.

by polish standards, they are on the expensive side. still quite a bit cheaper then those in more western countries (uk / germany / etc) or the us im sure. then again any gains there are offset by our (wtf, arnt we like 500km from the mothership?!) more expensive parts prices

I'm not realy agreed with the shavings of the clutch ,flywheel and starter story of the mechanics
Because DCT cars have no shavings of the clutch and have no flywheel , and i have like you know the same problem as you
Please correct me if i'm wrong....

[anom3]

yep this is true, i thought about this as well.

i will know more tomorrow. will get a call about 10am my time (we are almost same timezone i believe) so i will let you know what they come up with.

Originally Posted by ///M Power-Belgium

I'm not realy agreed with the shavings of the clutch ,flywheel and starter story of the mechanics
Because DCT cars have no shavings of the clutch and have no flywheel , and i have like you know the same problem as you
Please correct me if i'm wrong....

[///M Power-Belgium]

Originally Posted by anom3

yep this is true, i thought about this as well.

i will know more tomorrow. will get a call about 10am my time (we are almost same timezone i believe) so i will let you know what they come up with.

Sounds perfect to me !

[s85e90]

Originally Posted by SenorFunkyPants

This from the "SIEMENS MS 42.0 ENGINE CONTROL SYSTEM" manual for a E46 M3 which has a high pressure VANOS system.
http://www.beisansystems.com/misc/SE...ROL_SYSTEM.pdf

"When the engine is started, the camshafts are in the “fail-safe” position (deactivated). The
intake camshaft is in the RETARDED position - held by oil pressure from the sprung open
solenoid. The exhaust camshaft is in the ADVANCED position - held by a preload spring in
the actuator and oil pressure from the sprung open solenoid.
After 50 RPM (2-5 seconds) from engine start, the ECM is monitoring the exact camshaft
position.
The ECM positions the camshafts based on engine RPM and the throttle position signal.
From that point the camshaft timing will be varied based on intake air and coolant temperatures.
The double VANOS system is “fully variable”. When the ECM detects the camshafts are in
the optimum positions, the solenoids are modulated (approximately 100-220 Hz) maintaining
oil pressure on both sides of the actuators to hold the camshaft timing."


Again this is for the VANOS on an E46 M3 (can't find the same document for the E9x) but if the startup system is similar for the E9x M3 then the cycle goes:
VANOS is in default (fail safe) position
start engine
wait 2 secs
ECU checks VANOS positions
ECU makes some adjustment to VANOS and the clacking noise occurs.

The adjustments are based on throttle position, RPMS, air and coolant temps". As the clacking only occurs when the engine has been left standing then perhaps its a cold coolant temp that initiates the noise rather than a loss of oil pressure in the VANOS system.....on affected cars.

totally diff from e9x. e46= High pressure system whereas e9x is a low pressure system

[SenorFunkyPants]

Originally Posted by s85e90

totally diff from e9x. e46= High pressure system whereas e9x is a low pressure system

I know it is....however the startup sequence could well be similar.

[///M Power-Belgium]

Originally Posted by SenorFunkyPants

I couldn't say...you could try messaging "Regular Guy", he may have a better understanding of the VANOS than I do.

Just tried to PM Regular Guy , but it was not possible !
Think it's a personal setting for not receiving PM's .

[SenorFunkyPants]

Originally Posted by ///M Power-Belgium

Just tried to PM Regular Guy , but it was not possible !
Think it's a personal setting for not receiving PM's .

I've just found out he is currently banned!

[///M Power-Belgium]

Originally Posted by SenorFunkyPants

I've just found out he is currently banned!

No !....That's realy...WTF ?!?!
Sad to hear this ,it's a man with "a lot of knowledge" when it's about our S65 !
Actualy we could use him on here in this thread !

[FormulaMMM]

Originally Posted by anom3

he also said if there was an issue with the vanos, chances are quite high i would be able to hear it not just on cold start.

And this seems right to me. That's why I asked the question at the top of the page. Coming from E39 M5 world, the vanos issue wasn't something that was cold start dependent or limited to cold start, and it progressed in severity, triggered ses, etc. That's not happening for the E9X.

Anyways, vanos, starter, whatever the source I hope you get a solid answer from this shop. Make them diagnose with certainty before they replace items please!

[anom3]

spoke to the mechanics this morning. not the news i was hoping for but:

a) they were unable to locate the location of the noise. most likely not the starter tho. they said it sounds like it is vanos related. but he made it very clear that they are uncertain. the main issues they had was that one it was much quieter then usual this time around, and two it lasts for just a fraction of a second. the one bit of good news with this is that they know my style, i come with a pocket full of cash ready to spend, usually taking the 'is this it' responsibility onto myself. they could quite easily say 'yep, replace both vanos' for $XXXX.XX and suck me into an un-needed repair. this is not the case with them. so good news there.

b) the chain tensioners did not arrive this morning. delay at bmw, so they did not get replaced yet.

c) one bit of good news, the did the final check valve. so if the noise persists (and it sounds like it does), i can say for certain that replacing the check valves did not help.

car gonna go back in on monday to do the chain tensioners and have them listen to it again. fyi : replacing the passanger side chain tensioner is quite a bit of a pain in the ass. a number of items need to be removed to gain access to the spot where its located (someone can confirm?).

will keep everyone posted.

[Rupes]

Originally Posted by SenorFunkyPants

I've just found out he is currently banned!

Whoa. This is a big deal. Who do we petition to get him back? Why are all these people being banned suddenly?

[FormulaMMM]

Appreciate the persistence man. Good luck.

[Leonardo629]

maybe you have checked already, but maybe your serpentine belt is loose or worn out?

[TX]

Just thought I'd chime in here. My 09 6MT (no tune) with 38K Miles does a very loud single THUNK (might be a series of very very quick thunks perhaps) right after it fires on occasion since purchased. It's most noticeable when cranked inside my garage. In fact that's really the only time I hear it. The first 3 videos in the first post sound more like a rattle than the normal thunk noise. My sound is exactly like post #15 http://www.youtube.com/watch?feature...&v=aRUnYVulXWA

Anyway, It's been there as long as I can remember and I'm not worried about it because I'm sure my rod bearings are going to fail WAY before whatever is making that noise fails.

[anom3]

Same issue then. My noise is exactly like that post too. Sometimes (rarely) worst.

I would bet if you were to get a nice clean recording of it and zoomed in you would notice its actually a fast sequence of knocks.

Check valves changed, noise still there.

Chain tensions came in today, getting replaced Monday.

Originally Posted by TX

Just thought I'd chime in here. My 09 6MT (no tune) with 38K Miles does a very loud single THUNK (might be a series of very very quick thunks perhaps) right after it fires on occasion since purchased. It's most noticeable when cranked inside my garage. In fact that's really the only time I hear it. The first 3 videos in the first post sound more like a rattle than the normal thunk noise. My sound is exactly like post #15 http://www.youtube.com/watch?feature...&v=aRUnYVulXWA

Anyway, It's been there as long as I can remember and I'm not worried about it because I'm sure my rod bearings are going to fail WAY before whatever is making that noise fails.

[anom3]

Didnt actually have a "poke" at iit, but visually, looked nice and tight.

Will have a look today.

Originally Posted by Leonardo629

maybe you have checked already, but maybe your serpentine belt is loose or worn out?

[anom3]

Thought I'd mention the following, as I spent a few hours at the mechanics yesterday as they were replacing my center console yesterday.

a) They did not have the noise happen AT ALL twice when the car stayed there over night. Once in the AM after it sat all night, and then we tried again right before I left and the car sat about 5 hours. Not a peep. Very strange as it happens EVERY time for me (when the vehicle is cold started). Only difference I can see is they had the lights at "0". Their shop is currently un-heated as its warm enough here. Like I said, very very strange... Happens EVERY single time here... 1 other thing that was 'different' then usual the car had 1-2 meters of neutral-pushing (while off) to align it with the jack. Sequence of events looked like this:

Wed 4-5PM : Last check valve changed (passenger side, lower one)
... Car sits over night ...
Thrus 9AM : Cold start, 4 people listening to it... Not a peep. Perfect start.
Thurs 11AM : Everything required to get the check valve replaced gets put back together. Quite a bit of labor required to do this btw.
Thurs 2PM : Cold start, 2 people listening to it... Not a peep. I was present for this btw.
Thurs 11PM : Back at home, cold start after it sat for about 7.5 hours... Noise present :/

b) I can say with 100% certainty, changing the check valves did not solve the issue.

c) Chain tensioners next, sometime around Monday.

d) If the chain tensioners dont do it, I will have them replace the starter solenoid. This should clear starter related issues as they will get a good visual on it, as well as knocking off "slow gear kickback" from the list of possibilities.

e) I gave them the PUMA # from the post by M3PO (where he had his vanos replaced). They were unable to pull it. The system said its not valid :/