
07-20-2008, 03:30 AM
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Registered User
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Join Date: Jul 2008
Posts: 5
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1997 e420 compression, Knock, Missing problem
I have a 1997 E420 with 79K on it. It has a knock that sounds like it is coming from cylinder 7. Here is a link to what is soundl exactly like although it is not my car.
http://www.youtube.com/watch?v=Qeqm8d660yw
I have removed the covers and checked, rmoved, cleaned all of the oil tubes and they were all fine with no visible problems under the covers. I am also reading misfires on the obd2 reader from all cylinders on that head and the car idles and runs terrible.
I have changed the Plugs and only started and run it a few times since changing them. I just pulled them to do a compression test and they are pretty black with carbon. The drivers side seems much worse than the passengers side. I did the compression test with all of the plugs out and the engine was cold and this is The PSI I got on cylinders 1-8 respectively 204, 200, 209, 207, 210, 190, 140, 110. # 7 at 140PSI is the one I thought was noisy. What could this mean? Considering this along with the knock and miss problem it seems like it would rule out the Spark Knock or the catalytic converter because that would seem to affect all cylinders on that head equally. Could a stuck lifter cause the knock and the compression problem? How in depth is a valve job on these cars if it is a valve?
Thanks
Ben
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