kth286
MB Enthusiast
On mine they essentially alter the effective length of the inlet manifold at certain revs to provide better low down torque and higher power at higher revs.
The flap in one position will cause the inlet mix charge to take a longer route into the inlet valves, and the flap in the other position will alow gases to take the shorter route.
They do work in conjuntion with the variable inlet valve timing which is advanced and retarded to get similar effects as above.
Both are controlled by the main engine ECU signals.
The flap in one position will cause the inlet mix charge to take a longer route into the inlet valves, and the flap in the other position will alow gases to take the shorter route.
They do work in conjuntion with the variable inlet valve timing which is advanced and retarded to get similar effects as above.
Both are controlled by the main engine ECU signals.
alexander patie
Active Member
hello mark, have you asked this question on the other forum?
which engine is this? 112 or 613 perhaps?
which engine is this? 112 or 613 perhaps?
alexander patie
Active Member
for this thread's sake mark, identify your engine!
alexander patie
Active Member
ok, i knew that from the other side but thought you should be clear. why not post the fault code that leads you to ask this question? or give us a bit more on why the diagnostic chap you consulted thought it was a VVT fault - your car still does not have VVT.
the flaps promote swirl within the combustion chamber, which aids homogenisation of the intake charge when on egr cycle. this swirl also promotes quicker and more complete combustion due to mixing the charge during combustion. also, only having one port open at low engine speeds increases intake gas speed. despite the very advantageous sound of all the above, you will actually find that the flaps make very little difference to the engines performance. i have seen many with the linkage broken and know all this from experience in my day job - i am the technical department in an independent mercedes specialists.
VVT stands for variable valve timing, a feature which is ubiquitous on modern mercedes petrol engines. your diesel however does not have it. honestly, i would have noticed by now
the flaps promote swirl within the combustion chamber, which aids homogenisation of the intake charge when on egr cycle. this swirl also promotes quicker and more complete combustion due to mixing the charge during combustion. also, only having one port open at low engine speeds increases intake gas speed. despite the very advantageous sound of all the above, you will actually find that the flaps make very little difference to the engines performance. i have seen many with the linkage broken and know all this from experience in my day job - i am the technical department in an independent mercedes specialists.
VVT stands for variable valve timing, a feature which is ubiquitous on modern mercedes petrol engines. your diesel however does not have it. honestly, i would have noticed by now
OP
OP
proser
Active Member
Just for the collective 
I have an ongoing issue with my E320Cdi (210226 613 engine) where by it will faulter around the 4000rpm mark. If you push it gently to that level then it's like a very major mis-fire, but if you floor it to that point then the point will drop off so abruptly that it's like you have hit a stationary object at slow speed.
the code that get logged is P1354 - Cam/Crank synchronisation inplausable.
when I put if first on a code reader it would get logged at start up.
I even took it into a dealers and they couldn't find anything conclusive as to the cause of the error.
This week I managed to get it over to a mates of mine, who has several different workshop code readers, and now the code only gets loggerd when hitting the 4000rpm area. I can only put this down to changing the chain tensioner.
My mate put a call into a guy, that is very well respected within the diagnostics area, and he came back with that it was caused by the VVT (yes I know what this means) not working.
After a bit of confirmation, I know that this engine does not have VVT, therefore the info I was given was tosh!
Therefore I was asking the question about the flaps to understand what their role within the engine is.
I had a long chat with the service manager at my local dealers yesterday, and they are not aware of any issues with timing chains on the CDi range of engines and could not put 'hand on heart' and say that replacing the chain will resolve my problem.
The price from them was around £700 but did talk about me doing the job, but I did hint about not having the correct chain riveter.
I do think that it could be the chain as replacing the tensioner has changed when the fault code is logged.
I have an ongoing issue with my E320Cdi (210226 613 engine) where by it will faulter around the 4000rpm mark. If you push it gently to that level then it's like a very major mis-fire, but if you floor it to that point then the point will drop off so abruptly that it's like you have hit a stationary object at slow speed.
the code that get logged is P1354 - Cam/Crank synchronisation inplausable.
when I put if first on a code reader it would get logged at start up.
I even took it into a dealers and they couldn't find anything conclusive as to the cause of the error.
This week I managed to get it over to a mates of mine, who has several different workshop code readers, and now the code only gets loggerd when hitting the 4000rpm area. I can only put this down to changing the chain tensioner.
My mate put a call into a guy, that is very well respected within the diagnostics area, and he came back with that it was caused by the VVT (yes I know what this means) not working.
After a bit of confirmation, I know that this engine does not have VVT, therefore the info I was given was tosh!
Therefore I was asking the question about the flaps to understand what their role within the engine is.
I had a long chat with the service manager at my local dealers yesterday, and they are not aware of any issues with timing chains on the CDi range of engines and could not put 'hand on heart' and say that replacing the chain will resolve my problem.
The price from them was around £700 but did talk about me doing the job, but I did hint about not having the correct chain riveter.I do think that it could be the chain as replacing the tensioner has changed when the fault code is logged.
alexander patie
Active Member
right, that's better . the flaps can cause problems we have not yet discussed, namely that they can become detached and bounce around the inlet ports playing chicken with the inlet valves. you will understand that this is not good . this is only really common on the 612 engine with the plastic manifold, i have never known it happen on the 613 but i guess there is a first time for everything. certainly worth checking the linkage right across the underside of the manifold for any signs of problems though. otherwise your chain stretch theory is fair, but would not explain the rough running, only the fault code. the problem i mentioned with the pump IS known by mercedes, but only listed for the 611 engine i believe, could still happen to others. mercedes employees are strongly discouraged from admitting to common faults if they are not officially listed as such.
certainly it is worth checking the timing, but i suspect your problem lies elsewhere. did changing the tensioner affect the runing in any way?
. the flaps can cause problems we have not yet discussed, namely that they can become detached and bounce around the inlet ports playing chicken with the inlet valves. you will understand that this is not good . this is only really common on the 612 engine with the plastic manifold, i have never known it happen on the 613 but i guess there is a first time for everything. certainly worth checking the linkage right across the underside of the manifold for any signs of problems though. otherwise your chain stretch theory is fair, but would not explain the rough running, only the fault code. the problem i mentioned with the pump IS known by mercedes, but only listed for the 611 engine i believe, could still happen to others. mercedes employees are strongly discouraged from admitting to common faults if they are not officially listed as such.certainly it is worth checking the timing, but i suspect your problem lies elsewhere. did changing the tensioner affect the runing in any way?
OP
OP
proser
Active Member
The rough running is only at the 4000rpm level and not at any other time. The flap linkage seems to be okay with no unduely resistance and the servo motor looks to be working.
Nothing noticeable in the running by changing the tensioner, but there was a noticable difference in the free length between old and new
So if the new tensioner is taking up more slack in the chain, and therefore the fault code is only coming on at 4000rpm, where the parameter tolerances are less, then it would possibly point to the chain.
Nothing noticeable in the running by changing the tensioner, but there was a noticable difference in the free length between old and new
So if the new tensioner is taking up more slack in the chain, and therefore the fault code is only coming on at 4000rpm, where the parameter tolerances are less, then it would possibly point to the chain.
alexander patie
Active Member
a new tensioner with more tension would further retard the timing - we might expect the code to come on at lower rpm.
i am thinking your fault code MIGHT just be a red herring. there are other failures that will not necessarily log codes. check the valve timing mark, chain wear is certainly not a usual fault on this engine, but beware the extra loads from a failing pressure pump as i have said. i am wondering about a loose flap, have a good look across the linkage to see if any of the arms have dropped, even a tiny bit!
i am thinking your fault code MIGHT just be a red herring. there are other failures that will not necessarily log codes. check the valve timing mark, chain wear is certainly not a usual fault on this engine, but beware the extra loads from a failing pressure pump as i have said. i am wondering about a loose flap, have a good look across the linkage to see if any of the arms have dropped, even a tiny bit!
OP
OP
proser
Active Member
I will test the issue with tensioners and put the old one back in and see if the code shows at start up again.
I will have a look at flap arms and the timing, but wont be for about 2 weeks due to work and going to the MB World event this Sunday. :bannana:
If I am going to look at the timing, then I will arrange to make sure parts are available if need to change the chain.
I will have a look at flap arms and the timing, but wont be for about 2 weeks due to work and going to the MB World event this Sunday. :bannana:
If I am going to look at the timing, then I will arrange to make sure parts are available if need to change the chain.
alexander patie
Active Member
ok, would be great to find the answer here. and you are CERTAIN there are no ther codes being logged? enjoy the MB world trip, but don't believe the hype!
