EGR - Does this make sense ?

Discussion in 'Engine' started by Tony Russell, Sep 29, 2009.

  1. Tony Russell

    Tony Russell Active Member

    Jul 21, 2009
    Glasgow ish.
    Vaneo. 1.7CDi. I know. Stop laughing ! I need an MPV and it had to be Mercedes. OK ?
    I wrote elsewhere on this forum about mass amounts of smoke from a Vaneo 1.7CDI. This is a long one, so best put the kettle on.

    Some Video

    Every time I thought I had the problem fixed, it came back eventually, so I kept trying different things, but given that I fixed it, and it returned intermittently, I went looking for other "feeds" down the line.

    So I'm looking for a bit of comment on my logic.

    I previously cleaned out the EGR without removing it, and it seemed not to fix it, then magically a day or so later the exhaust was clean.

    After a couple of weeks, it was back to smoking heavily on take off and high revs under stress.

    So I took the EGR out and it was (not surprisingly) filthy at the end I couldn't reach.
    So I cleaned it right up and lubricated it. I verified it was working by depressing the valve and blocking the diaphragm and it held.
    I verified in situ that it was opening and closing by the engine vacuum and closed it all up, but it was still smoking.

    Then I noticed a kink in the tube which tee's off the brake servo and turbo feed and loops over to the EGR via a solenoid.
    How the kink got there is another story - looks to me like it was clamped by the pollen filter cover and only the dealer ever removed that.

    So I cut back the hose a bit and rejoined it on the tee, adding some heatshrink tubing to give it a bit more kink resistance until I get a new length of hose.

    Now that didn't sort it. Not immediately.
    For the next day - 10 miles or so, it was smoking away, then just stopped and went clean.

    I'm thinking now that the kink was the problem, and every time some work got done, it got moved and unkinked for a bit, then got misshapen again, hence the reason the problem returned erratically.

    What I don't understand is why it would take several miles to stop the smoking ?

    Could it be because some much was left in the turbo dept and took a bit to blow through, or the same of the EGR ?

    Or am I barking right up the wrong tree ?

    One things for sure, while it's clean just now, I'd best get it MOT'd pronto.

    BTW - I couldn't get the hose to stretch over the tee without heating it with a heatshrink gun. Is this the right thing to do ?
    Seems a bit drastic to me as I doubt it would shrink back.

    Any opinion welcome.

    Last edited: Sep 29, 2009
  2. 280gee

    280gee Active Member

    Nov 13, 2007
    Costa Geriatrica
    W210, W124
    Looks like an excellent bit of fault-finding, and your supposition about the kink/unkink after the dealers 'expert' treatment was right.

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