Can't remove the Oxygen/Lambda sensor
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Thread: Can't remove the Oxygen/Lambda sensor

  1. #1
    Saabisti
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    Mar 2006
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    Its all in the title,

    I have the exhaust front pipe off and have tried clamping the sensor tight across the flats in a big vice on the bench and pulling on the exhaust pipe with no success, does anyone have any suggestions for techniques to get then apart.

    Thanks

    Richard

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  3. #2
    Full throttle mark e's Avatar
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    Put the exhaust pipe in the vice (padded). Apply a blowlamp to the the area around the lambda fitting and get it as hot as you can. Then take the longest wrench you have to the lambda.

  4. #3
    Saabisti
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    Put the exhaust pipe in the vice (padded). Apply a blowlamp to the the area around the lambda fitting and get it as hot as you can. Then take the longest wrench you have to the lambda.[/b]
    will try it today...

    Thanks

    Richard

  5. #4
    will try it today...

    Thanks

    Richard[/b]
    Not being funny, but why are you replacing it? If it's simply in result of the Lambda sensor error code being thrown, it's usually fixed by ensuring all the hoses are not split. That's how I fixed mine anyway, and used an OBD2 device to reset the code. Disconnecting the battery once fixed also clears the codes.



  6. #5
    Motor Mouth
    Join Date
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    Zeitgeist,

    You have been lucky. I consider the Lambda Sensor to be a 100k replaceable item. I think most 9000ers have probably had to replace one at some time. Mixed reviews but there are stories of pattern parts not suiting very well so best to go for a Bosch. I buy from Just Sensors in Hull who do a 4 or 3 wire replacement with connector block for about £40. 3 wire ones even with an additional earth line don't seem to work for long before the CEL comes on again if your vehicle is currently fitted with a 4.

    Don't know why but they recommend using the screw in connectors and NOT to solder the wires together.

    Richard,

    I sypathise with you. My Aero one was a complete pig to get out. I think it is down to the Stainless of the sensor and of the exhaust boss 'firing' together. You just need a tiny rag of swarf in the threads to really seize it up solid. Since I knew I was replacing the sensor I cut the wire close to the sensor so as to get a good quality ring ( I think 22mm ) spanner over it. It was still really tight.

    Might be worth running a tap down the threaded boss once you get it out to clean up the threads. I don't think there is a suitable reassembly grease since it can get cherry red in there at times. Even copper slip doesn't work. Best assemble dry.

    Paul @ Kippen.

  7. #6
    Saabisti
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    I got it off in the end, I left if soaking in Holts Rustola for a few days, then clamped the sensor in the vice very tight, got the mrs to sit on the bench to weigh it down and swung off the exhaust pipe and it finally started to move.

    I suspect the three wire sensors indicate a fail early due to the fact that there is on earth return for the sensor and so the return line is all the way through the exhaust to turbo to manifold to engine block. Very likley that this would result in either false readings or a sensor failure indication. I will be fitting a four wire replacement for this reason.

    I suspect that it is irecomended not to solder the wires due to the nature of the wires, it is that funny high temprature wire and some solders do not work very well and can easily produce a dry joint, if not imediatley then after a while of heating and cooling cycles, I notice most of the kits include crinps or terminals of some sort to make the connection with.

    Cheers

    Richard


  8. #7
    I believe the problem with soldering oxygen sensor wires is that the sensor needs a supply of reference air to the inside of the ceramic cup that sits inside the downpipe.

    Solder the wires and you quite possibly seal it off.

    As designed the reference air comes from the inside the ECU, down the wire gaps, through the sealed connector, then down the wire gaps again into the ceramic cup.

    Yes, I know this sounds a bit hair brained, but it is how it was explained to me when I worked on emissions systems in the motor industry.

  9. #8
    Full throttle mark e's Avatar
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    Yes, I know this sounds a bit hair brained[/b]
    Indeed it does! I think you'll find that lambda sensors draw their reference external air either via vents in the body of the sensor or in the gap between the wires and outer sleeve. They won't be drawing air in down the copper wires as this would lead to oxidation and brittleness of the wires.

    Soldering is not recommended because the joints are in too arduous an environment with the heat and vibration.

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