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Not 'O' Rings

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by M80, Oct 25, 2012.

  1. M80

    M80 Senior Member

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    Any pointers appreciated before I start to delve under the bonnet.

    It's the 270 CDI. Larisa complained She had trouble starting it a few days ago, it's been alright since.
    This morning it's a bit cooler out there and it failed for her, so She's scooted off in mine.
    A short time later it started for me without too much problem so I thought fuel line 'o' rings. Just now I went to start to go and get some, no go.

    The battery is very healthy but no start. I feel I can discount the 'o' rings now as any air would have been bled through a short while ago and there would now be some warming under the bonnet.

    My thoughts are to start at the fuel pump, then consider the injectors.
    Any other try this ideas welcome.
     
  2. turbopete

    turbopete Senior Member

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    id still try o rings first. start with the cheap easy things
     
  3. brandwooddixon

    brandwooddixon Senior Member

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    No problem with glow plugs?
     
  4. Naraic

    Naraic Moderator

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    While it is cranking can you observe the fuel lines to see what's happening?
     
  5. OP
    M80

    M80 Senior Member

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    Glow plugs are fine, well the light goes out and stays out. On these it has too get pretty cold for the glow plugs to affect a start.

    I'm on my own so can't observe the lines while it's cranking. Not till the lady gets home later anyway.

    So I've been to MB and can only order the 'o' rings, they replace the whole pipe (or pipes) if they suspect the same so don't carry just the rings. An interesting way of how to use more of the customers money don't ya think ?

    12 miles there, inside maybe 15 -20 minutes and an issue to start again. Cranking much, occasional splutter, eventual start. I think they may ask me to hide it round the back when I go back for the rings tomorrow.
    If a ring was sucking so readily I would also expect it to pass some under pressure. There is no smell of diesel under the bonnet so no passing.

    As you say Pete it makes sense to replace the rings anyway, nothing lost, rings eliminated, and more reliable for the next few years. And it might just be that anyway ??

    Thanks for all thoughts so far.
     
    Last edited: Oct 25, 2012
  6. mattkh

    mattkh Senior Member

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    Hi
    I wonder if it is any of the position sensors playing up.
     
  7. brandwooddixon

    brandwooddixon Senior Member

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    Hmm, crankshaft sensor maybe?
     
  8. DB autos

    DB autos Senior Member

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    Have you checked injectors does it start with easy start.
     
  9. OP
    M80

    M80 Senior Member

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    Thanks to all for the thoughts.
    Yesterday evening with Larisa cranking I could see air in the lines in / out of the pump, that would indicate 'o' rings.
    This morning much cranking it started, as expected really.
    Left running for a few minutes turned off, went back to it to drive over and collect the rings nowt, even with loads of cranking. Which indicates something else.
    As I've seen the air in the lines and wouldn't expect 2 issues together I'll replace the rings and then see what we have.
    So the motor bycycle is charging, as I've become addicted to sailing it sits looking pretty more now and ends up with a flat battery. That reminds me I left it on boost.........

    Well at least that's ticking over nicely now, time to put all the protective armouring on.
     
    Last edited: Oct 26, 2012
  10. toby1

    toby1 Senior Member

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    Is there fuel in it?
     
  11. alexanderfoti

    alexanderfoti MBO Forum Supporter Authorised Forum Supporter

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    ^LOL

    This doesnt appear to be a classic O ring issue, as normally when they have been started, they draw enough fuel up and bleed enough air out for it to not be an issue.

    Saying that, it could be another O-ring or a fuel filter issue.

    I would get it plugged into STAR, I know its easy to say, but you can at least see if its building rail pressure ETC, before you start stabbing in the dark.
     
  12. tony jr

    tony jr Senior Member

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    I would get a leak off test done you will probably find that the high pressure seals have gone on one or more injectors giving an excessive leak off that prevents the rail pressure reaching the required threshold to fire. Alternatively it could be the seals on the high pressure pump - these usually start failing in cold weather but normally cause a fuel leak from the pump.
     
  13. OP
    M80

    M80 Senior Member

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    Fuel filter replaced last month, 500 miles ago.
    Yes fuel, no Star as it's the Gr Cherokee. No faults on the EML327 though current or historic. But I'm not sure that's of value.

    5 'o' rings replaced, I can't see more on the lines. Cranking much and no go. The air can be seen in / out of the pump still.
    My guess no is pump or as said injectors. I'll try the easy start (WD40 in this case) trick when Larisa gets back.

    By now I would expect to see low fuel pressure on the EML, hence not sure of it's value.
     
  14. alexanderfoti

    alexanderfoti MBO Forum Supporter Authorised Forum Supporter

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    Ah sorry, I thought it was the C320 CDI.

    I would do a leak off test first, if you were near me I would offer to do it for you, as I have the kit still from when I had issues with my car. I suspect with the problem as bad as yours it would be immediately obvious, but like you, I would expect an error code.
     
  15. tony jr

    tony jr Senior Member

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    Martin have you got anywhere with this?
     
  16. rpe2

    rpe2 Senior Member

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    How much fuel is in the tank?
     
  17. OP
    M80

    M80 Senior Member

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    I haven't had chance over the w/e, family wedding and other stuff.
    Some time ago ADR in Macclesfield repaired my car and screwed up the tracking with their Hunter machine. Today, due to the car tramlining some I went more local for tracking. The cords are now showing on the insides of the front tyres. So besides referring back to the insurance for resolution I've refitted my winter set so I'm legal.

    It seems to be problem after problem this week.

    My thoughts for this problem are to blank the return of each injector, in turn, and try to start.
    That failing I think it's pump strip down.

    'O' rings changed, so should be eliminated.
    Plenty of fuel, but hadn't considered the possibility of fuel pump, cheers. Mind once running is happy, relay perhaps.
    There is still air to be seen in the lines though.
    CPS is usually a hot issue, this is happy when hot, definitely a cold issue.
    Fuel filter near new.
     
    Last edited: Oct 29, 2012
  18. tony jr

    tony jr Senior Member

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    With your ELM327 can you measure the rail pressure? It needs to be over 200bar (I think - unless someone corrects me) for the engine to fire. If you have excessive leak off then it will not always reach the pressure threshold.
     
  19. OP
    M80

    M80 Senior Member

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    I think I've found it, but I'll know better after it's stood for a while.
    Although I could see air bubbles at the pump when I looked back at the filter I 'believe' I could see air bubbles travelling from the filter towards the pump. Better seen in the dark with a torch.
    Near new filter and new 'o' ring but hey ho.
    I've removed the union, wrapped with PTFE and reinstalled, now I don't see bubbles and if it's the same in the morning I guess a replacement of the new filter is in order ??
     
  20. alexanderfoti

    alexanderfoti MBO Forum Supporter Authorised Forum Supporter

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    I was going to suggest filter and filter o-ring first, but I thought it was a v6 cdi, which doesnt have a filter housing :( That could well be your culprit!
     

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