Missing diesel

Discussion in 'Shop Talk' started by Rob30, Apr 28, 2005.

  1. Rob30

    Rob30 Well-Known Member Supporter

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    What causes a diesel to 'miss'. I have a 40 hp diesel tractor that usually runs great, but ;ately it sound like it is missing at timesm mostly at low rpms.
     
  2. fordy

    fordy Well-Known Member

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    ...........Fuel must be injected into the combustion chamber at the proper time so as to allow the piston to compress it with the requisite pressure for it to achieve combustion . Lack of proper fuel line pressure would mean the fuel is arriving late . You could have intake\exhaust valves that are not sealing properly and allowing the pistion to push some of the air OUT of the combustion chamber prior to the fuel being injected . Could have a worn cam lobe which would cause a valve to operate to slowly or not at all . Stopped up fuel injector line . Piston rings maybe sticking and and allow pressure to flow into the oil pan area of the engine . etc , fordy .. :)
     

  3. farminghandyman

    farminghandyman Well-Known Member Supporter

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    I would have the injectors checked out, IN my experience they are usually the first place to check out,

    (this usly takes a special manual pump that pumps it up to pressure and you can see how it sprays the fuel It should spray in a fog and not a stream.)

    if they check out then have a compression test done and or have the injection pump tested,
     
  4. fordson major

    fordson major construction and Garden b Supporter

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    before you tear anything apart,check fuel filter,water trap and air cleaner.if memory serves me david brown 880? 3cylinder cav injection pump cav injectors . other thing can happen is cold start come on part way or the fuel kill stick slightly. when was the last time you filled it? may have watery fuel too. not sure if we still have partsmanuels/repair books but will check,have you the owners manuel?
     
  5. agmantoo

    agmantoo agmantoo Supporter

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    change the filters as suggested and buy a quart of product called Siloo and add that as per the directions to the fuel and let us know how it goes.
     
  6. Rob30

    Rob30 Well-Known Member Supporter

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    I will be checking it over tomorrow.
     
  7. fordy

    fordy Well-Known Member

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    ................You can bleed the Air out of each fuel line by starting the engine and simply unscrewing the nut ....Slightly....where each fuel line enters the combustion chamber . It should leak a slight amount of fuel then simply tighten it back up . fordy.. :)