knocking on start up??
Thread Starter
Junior Member
Joined: May 2012
Posts: 30
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2000 e55 amg
knocking on start up??
Ok gang help me out here. When I start the car in the morning I am hearing a knocking noise from the motor. I have tried to determine where the sound is coming from but no luck. The really strange thing is the noise stops abruptly as the motor goes through its warm up cycle. Almost exactly as the motor idles down. I will try to explain as best I can. On start up the car idles up and stays there for a minute or two. Then the rpms drop a little like the motor is stepping down. Then I goes to its normal idle speed and at that moment the knock stops. It never returns until the car has sat for 7 or 8 hours. Here are few factors to consider. I have either the purge valve or the purge cut off going bad. I have ordered but they are not here yet. Is there a early demise of this wonderful engine in the future or am I missing some thing.
MBWorld Fanatic!
Joined: Feb 2008
Posts: 1,280
Likes: 4
From: Bostonian Ma
2012 CLS63 AMG
Ok gang help me out here. When I start the car in the morning I am hearing a knocking noise from the motor. I have tried to determine where the sound is coming from but no luck. The really strange thing is the noise stops abruptly as the motor goes through its warm up cycle. Almost exactly as the motor idles down. I will try to explain as best I can. On start up the car idles up and stays there for a minute or two. Then the rpms drop a little like the motor is stepping down. Then I goes to its normal idle speed and at that moment the knock stops. It never returns until the car has sat for 7 or 8 hours. Here are few factors to consider. I have either the purge valve or the purge cut off going bad. I have ordered but they are not here yet. Is there a early demise of this wonderful engine in the future or am I missing some thing.
I'm sure the boys will chime in to help out-
GL!
Armani
