ec5780 Posted October 24, 2022 Posted October 24, 2022 (edited) Hello Looking for ideas here. I had a catalytic converter and lamda sensors stolen. I bought replacements online (onlineautomotive.co.uk) and a few months later it started tripping the engine management light - P0420: Catalyst System Efficiency Below Threshold (Bank 1). I'm now wondering about trying to get the catalytic converter replaced under warranty and wondering what is the best way to go about it? They understandably want to pick it up, but I need to use the car in the mean time if there is a delay until they send out a replacement or refund. Also wondering if there's a possibility they'll take it and then try to reject the warranty claim and then I'll be left out of pocket... Any ideas as to how would be the best way to do this - or at least to get as much proof as possible that it is indeed the catalytic converter as opposed to the sensor or something else? Thanks Edited October 24, 2022 by ec5780
Trevor Posted October 24, 2022 Posted October 24, 2022 I still maintain that I would not replace any components until the Oxygen / CO2 levels have been checked. Typically the Oxygen level should be as close to zero (0) as possible and the CO2 should be around 16% (from memory). A pre-test MOT emissions check should reveal the result. If the oxygen level is much higher than zero then you are drawing air through a poor weld, split or crack in the exhaust system or a poor joint/gasket and the result is what you are describing 1
ec5780 Posted October 24, 2022 Author Posted October 24, 2022 (edited) Thanks for responding again @Trevor I think I misunderstood what you meant by pre-mot test. I thought you were referring to some other type of test that they used to do before they do MOTs. I was asking MOT centres for a test to check the oxygen levels and they had no idea what I was talking about. I've had a few MOT emissions checks done since then. This is the most detailed report I've had, does that help? Scanned_20221023-0101-1.pdfFetching info... Edited October 24, 2022 by ec5780 clarify
Trevor Posted October 25, 2022 Posted October 25, 2022 Now that report tells a tale, the Lambda reading shows 1.09 which is outside of the operational parameters due mainly to excess oxygen levels and the sensor informing to the injectors to run rich. Look for an oxygen leak in the exhaust system starting from the manifold where it bolts to the head and work your way down the system (make sure you check the catalytic converter joints and bolts to ensure gas tight and place a rag over the rear to listen for hissing. A four gas or five gas test would show the oxygen levels high and this is more than likely the issue
ec5780 Posted October 25, 2022 Author Posted October 25, 2022 (edited) Thanks again Trevor. I think the Lambda reading shown on that report was 1.009 rather than 1.09. (Next to that line, the report says says 'OK'). Do you know where I could get a four or five gas test done? MOT stations don't seem to understand what I'm asking for, all they can do is the standard MOT test (which seems to pass on the second fast idle test - I've had this done three times) Update: Meanwhile I've found someone who does exhaust gas testing - http://www.mobile-car-servicing.co.uk/MOT-emissions.html - it but the prices quoted on the website is 拢120, which is more than the price of a new oxygen sensor... 馃槖 Edited October 25, 2022 by ec5780 Updated
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