2010 Audi Q5 3.2 (CALB) noise under 1-3 valve cover & #3 misfire

[Nmcracing]

I am trying to figure out what the noise is that sounds like a marble rolling around near the #3 cylinder of my 2010 Audi Q5 with the 3.2 (CALB) engine. I also have a misfire on #3 that I have not been able to figure out. I have cleaned the intake valves (walnut blasting) and I have replaced the #3 fuel injector. I have also switched the coil packs around and the problem stays with the #3 cylinder. I have removed the valve cover and looked at the valve train and I have not seen anything that is out of place or broken from what I can tell.

I should also add that I have performed a running compression check and Cyl #2 pumped up to 80 psi and Cyl #3 was from 70-75 psi.

Any help would be great.

Here is a link to the video of the noise. https://youtu.be/gVYgbamOHRI

Here is another video that I just took with the valve cover off. https://youtu.be/yN5p-HbSnwY

Thanks in advance.

[Gerry_Ramone]

hello this seems as if a valve spring was broken especially by the noise in fact if we watch carefully the video there is a spring that does not move I dare to assure this since it has been the problem in another Audis especially in the 4 cylinder more recent, in addition to that you already did the most basic tests without obtaining good results or different results the problem remains in cylinder 3, on the other hand I know that I do not have any score or anything in this forum but here in Mexico I worked 3 years in Audi and 2 in VW I hope you find it useful my opinion best regards

Sent from my TA-1039 using Audizine mobile app

[davidsain]

I do agree with the Valve Spring recommendation. Based on your description, the valvetrain is next. If not a bad spring, look at the valves and seats.

Sent from my SM-G935V using Tapatalk

[davidsain]

I do agree with the Valve Spring recommendation. Based on your description, the valvetrain is next. If not a bad spring, look at the valves and seats.

Sent from my SM-G935V using Tapatalk

Watching the video with valve cover off on cylinder three, watch the left sprung vs the right. You can even see how a bead of oil runs down the spring as it sits there, unmoving. Could be the keeper or broken valve stem.

Sent from my SM-G935V using Tapatalk

[SQive]

It could also be a flat lobe.

[Nmcracing]

So I noticed the valve spring not moving as well but I compared it to the other cylinders and it looks like the left (aft) intake valve for each cylinder moves like you would think. The valve on the right (fwd) moves very little at idle for all three of the cylinders that I checked. The valve in the video is the #3 fwd valve. I dont know if that is related to the variable valve timing and when that kicks in then those valves open.

[Nmcracing]

I took the Q5 to an independent audi/vw shop this morning and told them everything that I have done and they listened to the car and they said it sounds like the upper timing chain has slop in it. They recommended replacing both of the upper tensioners. I guess my next step is to take of the upper chain covers and take a look.

[RHawk]

Not seeing the intake valve move either!

Sent from my HTC6535LVW using Audizine mobile app

[RS6gmbh]

Check cam lobe it should be easy to see

Timing chain slop? I have no idea what they are thinking

[base14]

Holy smokes. How many miles you have on it?


Sent from my iPhone using Audizine

[audinutt]

What does a cam lobe look like? You can't tell with it runnin.. take some pictures and turn the engine over and take a couple more

Sent from my SM-G935U using Tapatalk

[Nmcracing]

Holy smokes. How many miles you have on it?


Sent from my iPhone using Audizine

110k

[Nmcracing]

What does a cam lobe look like? You can't tell with it runnin.. take some pictures and turn the engine over and take a couple more

Sent from my SM-G935U using Tapatalk

Here are some pics of the lobes on #3 and #2 cylinders.








#3 spark plug


#3 piston


RH Upper Timing chain Tensioner






Secondary air ports

[audinutt]

You camshaft has a flatspot on #3 this is why the valves aren't opening which is the reason for you misfire.

It's not timing tensioners, time to replace the camshaft or head.

-Richard

Here are some pics of the lobes on #3 and #2 cylinders.






#3 spark plug


#3 piston


RH Upper Timing chain Tensioner




Secondary air ports

[Nmcracing]

You camshaft has a flatspot on #3 this is why the valves aren't opening which is the reason for you misfire.

It's not timing tensioners, time to replace the camshaft or head.

-Richard

So I looked into the camshaft lift today and I don't think that the cam lobe has gone flat. It looks like the intake cam has two profiles for the lower RPM circuit, one for the fwd valve and one for the aft valve of each cylinder. Here are my results for each lobes lift:

Cyl #1 Fwd - .043" Aft - .127"
Cyl #2 Fwd - .044" Aft - .128"
Cyl #3 Fwd - .044" Aft - .128"
Cyl #4 Fwd - .044" Aft - .126"

If the lobe was to go flat I would expect to see lower lift numbers on Cylinder #3.

I ordered the incorrect cam lock tool last week and I am waiting for the correct one to come to me by middle of this week. Once I have the correct tool I am going to lock the 4-6 cam and take the cams and guide frame off and look at the rockers and lifters and see if I can see anything.

Here is my setup for measuring the cam lobe lift. I have a couple of old aircooled Volkswagen's and I had this setup to measure the crankshaft/flywheel end play and the total valve lift at the valve (non overhead cam).

[wt8d]

Have you checked tappet clearance on No.3 in&ex valves? Seen needle bearings on rockers worn out and created gap between cam lobe and roller. It causes noise and misfire.


Sent from my iPad using Audizine

[Nmcracing]

Have you checked tappet clearance on No.3 in&ex valves? Seen needle bearings on rockers worn out and created gap between cam lobe and roller. It causes noise and misfire.


Sent from my iPad using Audizine

I have a friend that also told me to look at the needle bearings when I get the cams removed. I just removed the cams and there is additional play in needle bearings on the #3 aft intake valve.

Here is a video of what I found.

https://youtu.be/2bdHqPYqXsM

[wt8d]

‘This happens only intake side, I assume the bearings are narrower than exhaust one, so the bearing is a little too weak?? Grad you found issue.


Sent from my iPad using Audizine

[Nmcracing]

‘This happens only intake side, I assume the bearings are narrower than exhaust one, so the bearing is a little too weak?? Grad you found issue.


Sent from my iPad using Audizine

I replaced the intake rocker and put it all back together this weekend. The noise and misfire has gone away so it looks like this was the cause of the issue.

Sent from my SM-N920T using Audizine mobile app

[Reggie]

Wow great work

[javierll]

I have the same car, and have the same problem, any mechanic can find the problem, now I buy the rocket arms and try to change them, but I want to make a question for you, you now if is possible change the rocker arms without take out the camshaft?

Sorry for my english and thank a lot for make this post, you help my a lot

[Nmcracing]

I have the same car, and have the same problem, any mechanic can find the problem, now I buy the rocket arms and try to change them, but I want to make a question for you, you now if is possible change the rocker arms without take out the camshaft?

Sorry for my english and thank a lot for make this post, you help my a lot

You have to take cam out to replace the rocker. I recommend getting the PDF of the repair manual on the Erwin site. You will need to get two different sealants and various bolts as they are single use. You will also need the tool to lock the cams. Make sure to mark and or take good photos of the gears on the end of the cams. It is critical that they go back in the same location. There are marks in the too plate that they should line up with but it can be hard to tell when trying to put it all back together.

Sent from my SM-N920T using Audizine mobile app

[a4lownslow]

How bad was your misfire at idle? I have a 2010 Q5 3.2 and I am battling the same issue, except I don’t really hear excessive noise under the valve cover. I have carbon cleaned the valves, replaced fuel injector, swapped coils/plugs, and the misfire staying on cylinder 3. As I watch the live misfire counter on vagcom it’s as if the cylinder is not firing at all at idle. Reaching a few hundred misfires within a couple minutes, car shakes heavily. Again only on cylinder 3 and it seems to smooth out as the revs increase and vagcom does show the number of misfires decreases almost stopping completely.

Compression was 200 on all cylinders except #3 was at 190. It also seems when I do the compression test 3 does not build compression consistently like the others but it does get up there. I have cranked the car over with the valve cover removed but don’t see anything obviously wrong. Thought about running it with the cover off like you.

Does this seem like a rocker arm/needle bearing problem? I am at a loss and would greatly appreciate your input before tearing things apart further!

[Tahoe5]

Hi nmcracing, I think I have the same problem, can you help me identify what manual you used from the Erwin site? Does this manual identify the part numbers for sealants and bolts that will be needed along with the rocker arm?

Thanks for putting this together!