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Matt, Mechanical Engineer
Category: Mercedes
Satisfied Customers: 22903
Experience:  BEng hons Mech engineering, in auto industry 22 years
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Mercedes CLS 320 cdi 2007 - I have just driven home after

losing acceleration when accelerating away... Show More
losing acceleration when accelerating away from a junction. I heard two pops then I couldn't increase revs above around 2000 rpm. So lost power. I have heard about exhaust manifold pieces breaking off and entering the turbo which would be seriously bad news so am looking for an alternative diagnostic please.
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I'd first check all the high pressure hoses post turbo/s for any split hoses or cracked metal pipes, also check the ends of the intercooler as its not unheard of to pop the end caps off under high boost.

If this is OK then check the small vacuum lines to the turbo and its connected control solenoid on the bulkhead, any cracks or leaks can give turbo issues

Also have a feel around with your bare hands with the engine running to see if you can feel any escaping gas under your touch. Another method is to use a soap and water solution sprayed onto any suspect areas - if there's a leak it'll bubble up with the engine running

Also check that the vacuum hose running to the dump / turbo bypass valve is intact with no leaks as if the dump valve is opening prematurely you'll be losing all your boost

Customer reply replied 1 year ago.
Hi Matt, thank you for your advice; it was good not to be so dramatic as bits of manifold in the turbo etc. Actually, it cleared when I next started the car so must have been an electronic mishap to do with the injectors - a temporary blip.