Austingtir

Trying to figure out whats causing my p0341 code iv been running around with for a while.

Replaced cam angle sensor with new one and took to workshop to check ECU functioning properly they said its fine and most likely mechanical timing issue. I also replaced the cam solenoids as the plugs were leaking oil out the top but they appeared to work.

The engine appears to run fine no dodgy rough idle and boosts ok but seems inconsistent and laggy at times (im still not sure if thats just how these are remembering I own a W211 E55 AMG which is obviously instant on the power with a supercharger).... again sometimes it feels fine not sure if its related to this.

So I have a Diagun v so camshaft deviation values were as follows:

N020_actual intake camshaft angle, bank 1 = 0
N030_camshaft deviation, bank 1 = 0

N040_Actual intake camshaft angle, bank 2 = -1.00
N050_Camshaft deviation, bank 2 = -3.00

I have never seen any values on bank 1 its always zero for both.
Bank2 N040 does sometimes cahnge to 0 but havent noticed any other values.
Bank 2 N050 does sometimes change to -4.00 but havent noticed any other values


So I pulled the cam covers off and made a crank pin tool like the factory timing kit And also just grabbed a piece of 6mm (actually 5.78mm) alloy flat bar I had lying around turned the crank until cyl1 at TDC and cams in the correct orientation as per the WSM.

What im finding is I can slip the 6mm flat bar into both slots on the two bank1 cams but not the two bank 2 cams.

I will have to probably spin the engine a couple few more times and see if I the same thing again.


My thoughts... A double row chain like this I wouldnt "expect" to stretch until 400+kms. The guides on the other hand could certainly wear but thats partly what the chain tensioner is there for. This car has 235k KILOMETERS on it NOT MILES. So certainly enough to get normal wear on timing components.

Is it possible to somehow measure the timing tensioner without pulling the front off the engine?


Id like to hear people like J's thoughts on this as im not sure how to attack this. I have seen other threads on here where people have pulled the entire front of the engine apart for nothing so im not keen on repeating that.

Those two bank 2 cams are out by literally a nats **** from my 5.78mm flat bar sliding in there. (Can anyone measure their timing flat bars just to let me know exactly how thick the factory timing bars are and the pin for that matter?) From what I can see any old piece of 6mm flat bar would likely be perfect cut to shape like the factory timing kit bars. Im thinking I might just put a piece of steel straping tape on the alloy flat bar and try that for that perfect machined fit into the ends of the cams.


Do I order 2 cam bolts and diamond washers and just retime those two cams and try that or should I investigate the timing tensioner and guides first?

It looks to me like the only way to evaluate the guides and timing chain/tensioner is to pull the front off...... Yikes.

Some pics:

hopsis

When I replaced my chain, I put the old and new side by side, there was ~5mm difference in lenght but of course the chains were intact. If I had cut them and pulled them straight, that amount would double to ~10mm. Engine had about 310tkm at that point and I was getting persistent cam over-advanced error codes from bank 1.

The car had some crappy tune in the engine ecu when I bought it. When I was diagnosing the poor performance (similar to what You're describing), the first thing I did was to flash original software back to the ecu. At first start after that, the check engine light was lit and there was a code for over advanced cam. That tells me whoever had the car flashed earlier, numbed the flag for that error code so it wouldn't light the cel or leave error codes to be read with diagnostic software. That then tells me that the actual fault with the cam position had been there for some time. Speculating even more will tell me that 250tkm isn't that far away from 310tkm and the timing chain in Your car could very well be worn enough to start causing trouble.

[offtopic]Yes, worn. I used the correct term even though everybody always talks about chain stretch. They do not stretch, they wear at the links.

Replacing the chain doesn't require pulling the whole front end off of the car but it does need to come loose and move a bit forward to make room enough to get access to all the front cover bolts. It's not overly complicated, it's just a lot of work and putting everything back together so that it doesn't leak oil at every seam is less than fun.

Austingtir

Theres a very good mercedes mechanic called Tasos Moschatos a greek guy that works out of dubai or UAE or something. He had a piece of alloy channel he puts his m156 iming chains into exactly the same way with notches cut and marked at each end to measure his chains (he's rebuilt literally hundreds of m156's).

If I end up pulling this down I might do it the same way he did it on his youtube video to compare a brand new chain to an old one. Its the only way to know for sure how these things wear.

In the end his claim was m156 chains dont wear any real amount upto 300+kms and he's almost never replaced one he always reuses the old ones where he can after checking them. Also goes onto say a worn chain is actually better than a new chain because its not going to wear the guides as much due to it being polished already from wear.

The m156 chains look very similar to these and I have on here so I might compare them to see if they are made by the same manufacturer.


This is why im very dubious about opening the front. But end of the day its probably the only way to know for sure whats going on with this thing.

brett968

I think your headed in the wrong direction with the timing chain. Before you go any further, I would recommend inspecting the rear of each intake camshaft and verify that all of the "fingers" are in place on the trigger wheel.

Austingtir

That was the first thing I did when I realized the cam sensor replacement didnt fix the issue. The fingers all look fine to me.

The fact the timing is out says it all really. But why its giving me an error on bank 1 when its bank 2 thats out is the only thing im wondering about.


Also im assuming when these "slip" the cam sprocket to the cam on the diamond washer its just one cam thats out or is it both on one bank like this? And is it by a small amount or alot??

I see in other threads people claiming they could physically move the chain around it was that loose. Iv got none of that everything I can see from the top (which isnt much really) looks fine and sounded fine when running.

brett968

Even the really small ones? They've been known to break off fairly cleanly. https://rennlist.com/forums/cayenne-...l#post11556194

But your camshaft deviation values are fine. Heck, they are better than my engine which has about 10k miles on it!

Maybe someone else will chime in but I still suspect there's something else amiss.

Austingtir

Here's a pic of them.... they look straight and fine to me. Is there only 3 on the bank 1 inlet cam? Anybody got a pic of a new bank 1 inlet cam?? Its hard to see down the back and the timing is locked in position atm.






Your right on the deviation values all my reading up about it showed anything upto 5 deg is normal. And as I said the alloy plate I used to try stick in there only JUST doesnt go in there. So far the only thing out of spec is those two cams on bank 2 as far as I can see.


This is why im on here asking for other opinions as I also dont get this. And im leary about pulling the front cover off for nothing. + its alot of money in parts.


Im leaning towards retiming the bank 2 cams and trying that if its still the same maybe go back later and pull the entire thing apart. But I still dont see how thats going to fix a p0341 on bank 1.



I saw a thread where J mentioned something about o rings inside the cam phaser? I probably need to find that thread and re read it.

brett968

Look fine to me also. That's a good thing! Hopefully the problem is something simpler to fix. I checked one of my spare (bore scored) engines and there are two small fingers and two larger ones.

Austingtir

I saw in another thread someone mention all zero's on one bank for cam deviation indicate faulty cam angle sensor.

But I took it to a workshop and they said they scoped all three sensors and decided it was a mechanical issue. But I also took the car off them before they were totally finished. (they didnt charge me for the work either). But workshops obviously love timing jobs.


The only thing I can think now is to swap the can angle sensor wiring between both banks and see what happens.

brett968

According to this, P0341 will trigger if the sensor signal is implausible. But if the signal was permanently high or low you should be seeing P0342/P0343. This explains why a missing finger on the sensor wheel would trigger P0341. I am not sure what would happen if the signal pin was left floating. You could try checking for continuity between the position sensor and the DME pins.

bigbuzuki

This is what I would do since you have the cam covers off.
Confirm physically the cam tone rings have 2 small and 2 large fingers.
Confirm electrical integrity of the suspect cam sensor wiring circuit.
Retime both your inlet and exhaust cams.
Replace the diamond washers and bolts on the inlet cam adjusters.
Replace the accessible 2 upper chain guides whilst your there.
Replace chain tensioner if your a perfectionist.
Watch this video as it features a Cayenne Cam issue (around the 4:45 minute mark)
.

hopsis

Just re-timing the chain does not require pulling the front cover off. If You already have the cam covers off, timing the cams is just about loosening the tensioner, loosening the camshaft end bolts, timing crank and cams and tightening everything back up.

What happened with my car was that I set it as close to perfect as I could. Then rotated the engine a couple of revolutions, put crank pin in and what do You know, camshaft setting plates wouldn't fit in place. I did it over again many times until I bit the bullet and swapped the chain. That thing has something like 240 or 280 links, cannot recall. If every one of those links is worn out for just 1/1000mm, it equals to ~enough for the setting to get out of whack. At least that's part of the problem. Another part is that when at timing setting point, one of the valve springs is actually trying to rotate one of the camshafts, if there is any play in the cam setting plates, that will instantly result in a couple of degrees deviation. I actually worked against that valve spring with a spanner when tightening the cam end bolts.

Austingtir

^^ Yep just checked the cam sensor trigger points on the end of the cams. They are 100% perfect. 2 small and 2 big on each cam as they should be and dont look bent in any way whatsoever so I can rule them out 100%

Im satisfied enough that I should be fine just retiming the cams on bank 2 (or even just leaving it for now as its within spec). It will take a few weeks for the parts to come in so in the meantime im going to put it back together and look at the wiring and see if I can get a cheap scope or something to look at this cam sensor output again.

I have spun the engine multiple times and I get the exact same result everytime.


Its got to be wiring or computer issue.

Austingtir

FYI 7.85-7.90mm or so on a machined crank pin seems to be near enough to perfect to lock the crank pulley. Any bigger and you cant get it to go in.

bigbuzuki

The fault code P0341 relates to bank 1 cam.

As a minimum I would be resetting your timing for both banks, paying particular attention to bank 1.

Try also reseating the ECU electrical connector that contains the contacts for bank 1 camshaft sensor.