Boost pressure too high
MBWorld Fanatic!
Joined: Feb 2012
Posts: 2,634
Likes: 1,219
From: Phoenix
222 S-65
Plug it in at MB to learn of what it thinks of itsself. Multiple MAP sensors are used. They tattle on plugged up air filters. Mind boost pressure ahead of charge coolers.
Check all vacuum lines used in controlling boost. They get hard and break with age. These are the lines that go to the wastegate actuators + the bypass valves on the 'cold side' (though it seems a malfunction of bypass valves on the cold side would not make overboost.) Be gentle! All that ish is too easily broken.
Verify that boost actuators move when calibrated pressure is applied to the lines. More a PITA to do then to say.
Whatever you do.... Don't break the plastic guy under the intake manifold + pray to whomever you are inclined it is not cracked/has broken nipples on it. Heads come off to service it (thanks Mercedes!). But if you get to go after that plastic guy buried a wayyyy under the intake you will then have the opportunity to do O-rings that seal the plate under it to fix/prevent a pressure fed oil leak. See.... Always a silver lining(?).
A smoke machine is very very helpful for finding PITA leaks.
Last edited by JohnLane; Aug 26, 2018 at 02:28 PM.
Thread Starter
Member
Joined: Oct 2015
Posts: 96
Likes: 7
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Thanks for your reply. Using a smoke machine for finding leaks is a good idea.
The car does behave completely normal, I have no CEL and no fuel cuts. This error is stored once in a while when I run a SD short test. It just bothers me because I don't want any errors, there is always a cause and this I want to find.
Car runs a tune. Maybe someone with a Renntech tune could let me know whether he got this error as well. I doubt it though, I have great trust in Renntech so I guess it is not necessarily related to the tune.
The car does behave completely normal, I have no CEL and no fuel cuts. This error is stored once in a while when I run a SD short test. It just bothers me because I don't want any errors, there is always a cause and this I want to find.
Car runs a tune. Maybe someone with a Renntech tune could let me know whether he got this error as well. I doubt it though, I have great trust in Renntech so I guess it is not necessarily related to the tune.
MBWorld Fanatic!
Joined: Feb 2012
Posts: 2,634
Likes: 1,219
From: Phoenix
222 S-65
Thanks for your reply. Using a smoke machine for finding leaks is a good idea.
The car does behave completely normal, I have no CEL and no fuel cuts. This error is stored once in a while when I run a SD short test. It just bothers me because I don't want any errors, there is always a cause and this I want to find.
Car runs a tune. Maybe someone with a Renntech tune could let me know whether he got this error as well. I doubt it though, I have great trust in Renntech so I guess it is not necessarily related to the tune.
The car does behave completely normal, I have no CEL and no fuel cuts. This error is stored once in a while when I run a SD short test. It just bothers me because I don't want any errors, there is always a cause and this I want to find.
Car runs a tune. Maybe someone with a Renntech tune could let me know whether he got this error as well. I doubt it though, I have great trust in Renntech so I guess it is not necessarily related to the tune.
Thread Starter
Member
Joined: Oct 2015
Posts: 96
Likes: 7
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Oh, believe me, that I am! Just hate when errors are stored, especially when they are related to the engine. You never know how the ECM responds to that. Maybe the car will decrease boost slightly when it recognizes this error too many times. I would prefer the error being gone.
