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    VW Golf 2000(w reg) 2ltr APK WVWZZZ1JZYW304047 Archived Message

    Posted by Andrew West on July 26, 2007, 9:56 pm

    The lambda was switching negatively on this one,so i suggested replacing the sensor & that perhaps there could be an ecu fault.The O2 sensor was replaced and brought back to me to check the emissions ready for it's MOT next week.The O2 sensor was switching at idle ,but not at cruise speed,so i cleared the code for O2 sensor "no activity" P0134(16518) & reset adaptions & told the customer to take for a drive.When he returned the O2 was switching ok ,so i checked the emissions & found that the co content was slightly too high and fluctuating from approx 0.19-0.65 %.The other gasses all looked ok with co2 at approx 14.5%,so i suggested that the cat would need replacing (the car had been driven for months with it black smoking apparently).
    The cat was replaced & now it keeps coming up with P0134 O2 no activity & the lambda stays rich approx 1volt viewed with scope.If the code is cleared the fuel trims adjust at idle & the lambda switches slowly,although the O2 sensor shows 800mv on scope & 600mv on eobd scan tool(using three diffferent scan tools).The ecu has now been tested as ok,but i still think that there is an ecu fault.The mass meter tests ok ,tps ok & coil ok.
    After clearing the code & the lambda starts switching, if the throttle is pressed,it goes into open loop & stops switching until the code is cleared again at idle.
    I read in the archives about these being fussy on lambda sensors,but with the ecu receiving 800 mv at the connector & the live dasta showing 600mv it still should be adjusting the fuel trims.
    I haven't checked the cam timing ,but the vacuum is good at about 20" & the belt hasn't been changed yet as it is low mileage & not yet due.
    The engine oil was very low(nothing on the stick) when my customer got the car to service & he also tells me that it does burn oil,with it blue smoking on start up & when revved.
    After testing the ecu i re-checked the emissions again & with the code cleared the emissions were about 1 % co with all other gasses good.
    Any help appreciated ,sorry for the long post,
    Kind regards,Andrew

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