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Garrett turbo, limp mode

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by Zeev, Apr 17, 2012.

  1. Zeev

    Zeev Member

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    Joined:
    Feb 20, 2012
    Location:
    Beer Sheva, Israel
    Your Mercedes:
    E220 CDI W210 OM611
    I am still trying to troubleshoot my limp mode. I started by cleaning the EGR valve. When I took it off, I found a 5-7 sq.cm piece of black plastic which looked like it broke off something. I could not find it's origin, but I saw plenty of gunk in the manifold. Anyway, I started by cleaning the valve and brought it to a condition it moves when pressure is applied from below (I guess EGR inlet). The spring seems to be strong, but it moves.
    The car was still entering the limp mode after first kickdown and had to be turned off to reset. It could, however rev high in P, emitting plenty of black smoke. I next decided to clean the manifold. Upon removal I found out the swirl valves had been removed, and so was the servo. In theory that would have been enough to put the car in limp mode, but the funny thing is it was fine when I bought it (2 months ago). Anyway, after I managed to assemble everything the right way (Thank you to Alex and Malcolm) the car drives, but stays in limp mode only. Just in case I tried to install a 5kohm resistor in a swirl motor plug (between a middle and pink wires, I think the white wire is ground) but it made no difference. My next suspect is the turbo. I checked that it spins when turned by hand, that oil reaches it and that the actuator arm moves when pressed down. What I do not understand, what regulates it? Exhaust gasses should spin it no matter what, I can't see any valve between the manifold and the turbine. Is there some kind of a flow diagram/manual available?
     
  2. oigle

    oigle Senior Member

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    Joined:
    Mar 15, 2005
    Location:
    Redcliffe, Queensland, Australia
    Your Mercedes:
    Currently 2003 ML270. 2012 Nissan Maxima 250SL.
    Your turbo spins up as a result of exhaust gas passing through the turbine blades. The higher the volume of exhaust gas, the faster the turbo spins. As turbo speed increases, inlet boost levels rise. There is no control on boost level until it reaches the predetermined maximum level, at which time the waste gate opens to maintain at that max level. If you have a VV turbo, then the position of the vanes control the turbo speed and boost.
     
  3. OP
    Zeev

    Zeev Member

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    Joined:
    Feb 20, 2012
    Location:
    Beer Sheva, Israel
    Your Mercedes:
    E220 CDI W210 OM611
    An update: it seems the vacuum actuator was faulty. Replaced it and all is well again. Thanks to everyone who took time to help me!
     

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