lumpy idle at 900rpm

Discussion in 'Volvo Forum' started by 4play, May 30, 2015.

Page 4 of 5
  1. May 31, 2015 #31
    4play

    4play Light Load Member

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    Well, sometimes it runs perfect then I feel the viberation come on slowly then it gets worse, when the engine has worked hard and is running hot it's really lumpy
     
    4play, May 31, 2015
    4play, May 31, 2015
    #31
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  3. May 31, 2015 #32
    benrab

    benrab Medium Load Member

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    Quebec ,Canada
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    One little test, when your engine is Hot tell me if the spin-on fuel filter on LH side of the engine come hot with your hands ?
    (Fuel filter under the hand priming pump) if you have two filter there i'm talking about the foward one.
    Ben
     
    benrab, May 31, 2015
    benrab, May 31, 2015
    #32
  4. Jun 1, 2015 #33
    4play

    4play Light Load Member

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    Nov 11, 2011
    Edmonton
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    At operating temp it's at 61 degrees celc
     
    4play, Jun 1, 2015
    4play, Jun 1, 2015
    #33
  5. Jun 1, 2015 #34
    4play

    4play Light Load Member

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    Nov 11, 2011
    Edmonton
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    I know at one point the shop found air bubbles in the fuel, so they replaced the fuel fitting on the front of the head, that seemed for them to fix the problem, and it did improve on a cold engine or if it doesn't work hard but ones it goes for a drive and things get working the viberation comes back. Could something be cracked maybe, and letting air into the fuel? Weird thing is that the truck doesn't loose prime
     
    4play, Jun 1, 2015
    4play, Jun 1, 2015
    #34
  7. Jun 1, 2015 #35
    4play

    4play Light Load Member

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    Nov 11, 2011
    Edmonton
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    Would a delta p sensor cause the viberation?
     
    4play, Jun 1, 2015
    4play, Jun 1, 2015
    #35
  8. Jun 1, 2015 #36
    benrab

    benrab Medium Load Member

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    Quebec ,Canada
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    Delta P is there for EGR flow calculation,with the test you ran with the Egr pipe disconnected that circuit is eliminated.

    If you are parked with the engine running at 900 Rpm and you look closely at the steering wheel and the dash (where the fuses are located) is it visual shaking ?
    Ben
     
    benrab, Jun 1, 2015
    benrab, Jun 1, 2015
    #36
  9. Jun 1, 2015 #37
    4play

    4play Light Load Member

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    Nov 11, 2011
    Edmonton
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    Everything shakes especially the dash, you can see it bounce up and down
     
    4play, Jun 1, 2015
    4play, Jun 1, 2015
    #37
  10. Jun 1, 2015 #38
    benrab

    benrab Medium Load Member

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    Apr 5, 2015
    Quebec ,Canada
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    Well, if you increase the Rpm to max RPM standstill then release the trottle quickly do you feel the same vibration when the engine is decelerate and past to 900 Rpm ?
    Ben
     
    benrab, Jun 1, 2015
    benrab, Jun 1, 2015
    #38
  11. Jun 1, 2015 #39
    4play

    4play Light Load Member

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    Nov 11, 2011
    Edmonton
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    Yes it does. I'm going to get a coolent test done now to check for fuel in the coolant. Aperently the davco filters are known to fail internally ant put fuel into your coolent. Which may explain why the truck is running hot all the time
     
    4play, Jun 1, 2015
    4play, Jun 1, 2015
    #39
  12. Jun 1, 2015 #40
    benrab

    benrab Medium Load Member

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    Apr 5, 2015
    Quebec ,Canada
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    Base on your answer about the vibration at 900 Rpm during deceleration the problem can be:
    Crankshaft Damper,
    Crankshaft itself.
    Bent connecting rod
    Clutch ,
    Flywheel (or bolts)
    Check if transmission bolts are tight to flywheel housing.
    Something major run unbalance i think. . .
    because during engine deceleration there is no injection in the cylinder then if the vibration is still there we can eliminate the fuel system.
    Look at the crankshaft damper when the engine is running for wobble movement ?
    About the Davco filter most of the time it's the opposite the coolant went into the fuel by a fail seal on the heat exchanger inside of the Davco filter.
    Let me know.
    Ben
     
    benrab, Jun 1, 2015
    benrab, Jun 1, 2015
    #40
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