Why does my diesel engine run on for a few seconds after switch off?

Currently driving a peugeot 306 d turbo, 150000 miles, no matter if engine is hot or cold when i turn engine off its keeps running for literally 2 seconds? Also when tubo comes in it puffs black/blue smoke like a chimney. Is it ready for the scrap yard?

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  • 1 decade ago
    Favorite Answer

    You ever heard of a car "dieseling" ? That's what your car is doing....it's when the engine continues to run until all the gas is gone from the cylinders. That's normal....a diesel engine can easily get 250,000 miles, some can get 500,000 IF you change oil, filters regularly. If you're stomping on the gas and the turbo kicks in the Black Smoke is normal for any diesel when you're stomping/accelerating......

    As for that "turbo-switch" answer I say <cough BS!> as you have this situation EVEN when your engine is COLD......plus there is no switch that continues to run the engine to cool the turbocharger, there's a switch to run the electric fans for radiators only.

    Source(s): International Harvester Trucks aka Navistar was one of the businesses in Ft. Wayne that produced diesel trucks....a diesel car is no different except for horsepower.
  • 1 decade ago

    This is because your car has a turbo timer.

    The Turbo Timer keeps your diesel engine running for a period of time in order to allow for gradual cool down of the turbo which is required inorder to prevent premature turbo wear and failure.

    All the other answers on this are way off!!!

    reggieman you stugge, Obviusly you dont know know much about cars do you?!! A lot of basic turbo timers are triggered by an engine being turned off, and not a temperature sensor, which would require it to be engine/turbo specific, and would be rather unreliable...

  • Anonymous
    1 decade ago

    i believe that since diesels do not use a conventional spark plug but use a"glow plug " instead that when you shut the engine off a "fuel shut off valve " is suppose to close and cut off the fuel supply to the combustion chamber, yours, if it is designed that way may not be stemming the flow of fuel completely therefore it is burning the fuel after you turn the key off...this may or may not have something to do with the turbo, but i doubt that. i probably have not been that much help, maybe it is ready for the scrap heap but i doubt it at 150 k miles...most diesels are good for a lot more miles than that...good luck

  • Anonymous
    1 decade ago

    i agree with the last answer...u have a turbo timer..it keeps the engine running because you should not turn off the car right after driving it...it just gives the turbo time to cool down...and gives it a longer life...

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  • 1 decade ago

    diesel cars have louder cool fans, so the engine seems like its still running

  • 1 decade ago

    It keeps running on the fuel that is remaining in the fuel line. I suggest you get your fuel line checked.

  • monaUK
    Lv 5
    1 decade ago

    my petrol car duz that!

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