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corsa 1.4 56 plate engine code p0171

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  • [All Models] corsa 1.4 56 plate engine code p0171

    HI newbie here
    i wounder if you kind people would help me with the above code problem. its a bit intermittent. but has thrown up the above code. has any one seen this before and what the cure was. Bank 1 running lean or something like that.
    we have noticed a lot of gunk in and around the filler cap and in the breather tubes from the engine to the carb etc. we have cleaned them out the best we can and changed the oil and filter but we were wondering if this gunk has got anywhere else which is causing the problem.
    Thank you very much

  • #2
    Welcome. First thing to remember is that this is a feedback system so the cause is most likely elsewhere. The most usual culprits are a vacuum leak around the intake, look for signs of perished hoses or if anyone has been working on the throttle body and it's not secure. Then bad airflow measurement, check the air intake hasn't been altered (eg aftermarket filter). Check also for any sign of an exhaust leak, even a leak after the sensor can cause the emissions to be out.

    Obviously make sure basic service items such as plugs and all filters are good, including particularly the fuel filter.
    1972 Viva restoration thread -


    • #3
      Thanks for your help, we will order some new breather hoses and fuel filter and will try that. may i ask why there is so much gunk in the rocker cover area and the breather pipes, what could have caused this, wrong oil?


      • #4
        The engine design has an inherent tendency for the top end to run a bit cool, that men's that water vapour (a byproduct of combustion) condenses and creates an emulsion. That is what the gunk is. It is worse on cars used for short journeys when the engine rarely gets fully up to temperature. Change the oil every 5k will reduce the tendency.

        Two other causes are to do with three headset or the seal in the timing cover behind the water pump, but only if you are losing coolant.

        A lot of them do it so it isn't anything to worry about. Try to get in a good long run regularly and do more frequent oil changes.
        1972 Viva restoration thread -


        • #5
          thanks very much


          • #6
            ok have changed tubes and took off rocker cover and cleaned out breather passages as they were blocked up of cream gunk.
            we also noticed that the cream substance is getting into the header tank again and the water has gone down again but no leaks on the floor..
            me thinks it could be head gasket..Click image for larger version

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ID:	110601there is also black crusty stuff around the top of the engine like burnt on soot very crispy.. is this normal?
            would the black crusty stuff be caused by over heating? thus head gasket?
            Last edited by CHROME; 04-06-2016, 09:37 AM.


            • #7
              If it's also showing in the header tank the you've got coolant and oil mixing.

              Just noticed my post above makes no sense - typed it on my tablet which tends to have a mind of its own. Should say headgasket or seal behind the water pump. If the seal on the water pump goes you tend to get coolant in the oil but not oil in the coolant. So my guess is this is more likely to be the HG.

              The black crusty stuff is what happens when oil is changed often enough. Old oil will still lubricate but it loses its ability to clean the engine so carbon deposits start to build up.

              Check if the cooling system is pressuring from cold - it will be under pressure when hot of course but if it builds up pressure when cold then that's a sign of cylinder pressure leaking into the cooling system. Squeeze the big hose running to the radiator to check.
              1972 Viva restoration thread -