almightybunghole
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- Jul 4, 2006
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Firstly, please excuse the long post, I have been having some engine troubles recently and I am hoping that the community can help me get to the bottom of it.
The car is a W164 ML320 CDI with the OM642 engine and about 133000 miles on the clock. The problems first started about a week ago on the way back from a 100 mile trip. The car went into limp home mode and the check engine light came on, a code scan revealed a turbo actuator fault. I purchased an aftermarket turbo actuator and fitted it without too many problems. In the process the air intake duct cracked where it meets the turbo.
Initially I put everything back together and planned to replace the duct, but wanted to see how the engine ran with the new actuator. Everything seemed fine at first, however after some time, particularly when the engine was warm it seems, it would log P0404 errors indicating an EGR function fault. I put this down to an air leak on the old intake duct and fitted an aftermarket replacement with new mass airflow sensors. I noted that there was definitely an audible air leak with the old duct fitted.
I fitted the new intake duct along with new sensors and confirmed that the air leak was gone. Unfortunately the EGR errors persisted particularly P0404 and P0401. In addition, now there is an audible coughing sound from the turbo as the revs drop between gear shifts along with very noticeable intermittent flat spots when accelerating. To be clear there were no errors or strange sounds before this entire episode started.
This is the point I am at at the moment. It seems unlikely to me that a whole host of components all failed at once, however every component I have replaced has not addressed the EGR errors. I have not yet removed the EGR but plan to do so. As a replacement part it is very expensive so I am not particularly eager to buy one on the off chance. The other possibility that occurs to me is that the aftermarket turbo actuator that I purchased is not behaving per the original spec but I'm not sure whether this could cause the EGR errors I am seeing. I have definitely confirmed that the turbo actuator is moving as I can see it when I rev the engine, also when it was off I confirmed that the lever on the turbo housing moves freely without catching.
Any advice or experience from the community would be welcomed as at the moment I am coming up blank.
Thanks in advance
George
The car is a W164 ML320 CDI with the OM642 engine and about 133000 miles on the clock. The problems first started about a week ago on the way back from a 100 mile trip. The car went into limp home mode and the check engine light came on, a code scan revealed a turbo actuator fault. I purchased an aftermarket turbo actuator and fitted it without too many problems. In the process the air intake duct cracked where it meets the turbo.
Initially I put everything back together and planned to replace the duct, but wanted to see how the engine ran with the new actuator. Everything seemed fine at first, however after some time, particularly when the engine was warm it seems, it would log P0404 errors indicating an EGR function fault. I put this down to an air leak on the old intake duct and fitted an aftermarket replacement with new mass airflow sensors. I noted that there was definitely an audible air leak with the old duct fitted.
I fitted the new intake duct along with new sensors and confirmed that the air leak was gone. Unfortunately the EGR errors persisted particularly P0404 and P0401. In addition, now there is an audible coughing sound from the turbo as the revs drop between gear shifts along with very noticeable intermittent flat spots when accelerating. To be clear there were no errors or strange sounds before this entire episode started.
This is the point I am at at the moment. It seems unlikely to me that a whole host of components all failed at once, however every component I have replaced has not addressed the EGR errors. I have not yet removed the EGR but plan to do so. As a replacement part it is very expensive so I am not particularly eager to buy one on the off chance. The other possibility that occurs to me is that the aftermarket turbo actuator that I purchased is not behaving per the original spec but I'm not sure whether this could cause the EGR errors I am seeing. I have definitely confirmed that the turbo actuator is moving as I can see it when I rev the engine, also when it was off I confirmed that the lever on the turbo housing moves freely without catching.
Any advice or experience from the community would be welcomed as at the moment I am coming up blank.
Thanks in advance
George
