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exmod110
Senior Member
150 Posts |
 Posted - 07/27/2015 : 05:52:08 AM
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I have a bit of a head scratcher on my hands.
2010 CE 300 with the DT engine 170000 km, none air brake unit. It's equipt with air susp, air fan, air seat, ad9 air drier, air tank auto drain valve and a tueflow 500 compressor. Complaint is that air pressure fluctuates from 30-180 psi at times and engine fan cuts in below 90psi as it should.. I have personally verified a 70-120psi fluctuation sitting stationary engine has to be above 1900-2000 rpm to show up. Will not present at idle or below 1800 rpm. air press will act drop from 120 to 80 with increased rpm and at times have difficulty building pressure to 120 again, return to idle and will build at normal rate. the drop can be fairly quick taking as little as 9 seconds. but not all the time.
So far I have ruled out by either swapping out with new parts, servicing component or isolating from system: susp air ride valve, air press sender unit, governor, air tank auto drain valve, serviced the compressor head with overhaul kit,the valve springs were slightly coked up no other noticeable concerns with the head and cyls looked to be in great shape.. (unloader valves intake and exhaust valves springs etc)after the cyl head was serviced the concern was not noted by the driver for aprox 2 weeks but hen returned. checked for leaks on the main outlet airline from comp to drier and drier to tank, checked for intake and discharge line restrictions, serviced air drier isolated engine fan from air system and can still replicate the concern.. the concern is directly related to engine RPM.. short of swapping out the compressor what am I missing here?? possible compressor gear nut loose or gear spinning on its shaft under load? Oil samples have not shown any metal contamination, and no noticeable abnormal noises from the compressor or engine..
anyone have any insight?
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2010 CE air pressure fluctuation
