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w204 c250d Cranking after fuel rail change. How long is too long?

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by Rick4495, Apr 16, 2019.

  1. Rick4495

    Rick4495 New Member

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    Joined:
    Oct 16, 2018
    Your Mercedes:
    C class estate/2010/250cdi
    Hi all,

    I have changed the fuel rail on my car, and have reassembled everything, but am having trouble getting the car started again.

    I have tried cranking the engine but made the mistake of stopping then starting cranking again . Apparently this will cause the pressure to dissipate which brings me back to square one again. Tried this a few times the engine started cranking slower and slower so before I fully emptied the battery have removed it from the car and put it on charge overnight.

    So how long is too long when cranking the engine to purge air from the system?

    Haynes reckons no longer than 10 seconds to prevent the starter burning out but some other posts have said to just crank it for ages.

    Also I have bought a can of easy start as another post mentioned to use it as a last resort. Do I have to open the air filter up to get to the inlet or am I ok to just spray it into the inlet by the bonnet catch?

    Thanks in advance .
     
  2. mrmb

    mrmb Senior Member

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    Joined:
    May 9, 2018
    Location:
    Galway
    Your Mercedes:
    W204 C200 CDI Sport Edition 125 2011 / W215 CL600 Bi-Turbo M275 2002
    The best option is to connect Star Diagnosis and use it to bleed the air from the system. On OM651 this is the only option. You can try to crank it but I do not think it will start easly.
     
  3. OP
    Rick4495

    Rick4495 New Member

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    Oct 16, 2018
    Your Mercedes:
    C class estate/2010/250cdi
    Well my car is on my driveway. So I won't be able to take it anywhere. Does that mean I'm screwed?
     
  4. mrmb

    mrmb Senior Member

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    Joined:
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    Location:
    Galway
    Your Mercedes:
    W204 C200 CDI Sport Edition 125 2011 / W215 CL600 Bi-Turbo M275 2002
    You can try to start it however give it a few minutes break after to 2 tries
     
  5. OP
    Rick4495

    Rick4495 New Member

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    Joined:
    Oct 16, 2018
    Your Mercedes:
    C class estate/2010/250cdi
    Well this is embarrassing .

    After failing to get it to start I tried a bit of easy start and it almost started but this time coughed a load of diesel out of one of the pipes between the injector and the rail.

    Turns out I had only hand tightened one of the unions.

    Tightened it properly fired up on my next next try relatively quickly without the need for easy start.

    Thanks for your help.
     
    daibevan, om613 and Blobcat like this.
  6. mrmb

    mrmb Senior Member

    Messages:
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    61
    Joined:
    May 9, 2018
    Location:
    Galway
    Your Mercedes:
    W204 C200 CDI Sport Edition 125 2011 / W215 CL600 Bi-Turbo M275 2002
    No problem. There is really huge pressure over there. Torque is quiet high for these lines :-D
     
  7. Uncle Benz

    Uncle Benz Senior Member

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    Location:
    West Sussex
    Your Mercedes:
    Mainly Mercedes
    Lol! That'll do it! Good result, well done!
     
    alexanderfoti likes this.

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