Thediver Posted December 9, 2021 Report Share Posted December 9, 2021 Hi All, Urgent need for some assistance. Car (986 3.2) in for MOT. Emissions failed and checking with a porsche specialist the AOS was confirmed needing replacement (I had small symptoms a few weeks before the MOT so indicated that to the garage). AOS now replaced and still emissions over the limit. The mechanic says the car was hot enough and the cat cleaner won't do much. Been reading about exhaust leaks (car has been making a metallic sound on low rpms from the exhaust lately) and not proper AOS replacement causing an air leak. What do you suggest? As other options will be new cats/lamdas Quote Link to comment Share on other sites More sharing options...
mike597 Posted December 9, 2021 Report Share Posted December 9, 2021 If you can post the failure sheet it might give more clues. Common failure points are the o2 sensors. Any access to live diagnostics? Quote Link to comment Share on other sites More sharing options...
M635uk Posted December 9, 2021 Report Share Posted December 9, 2021 I fitted aftermarket cats and the MOT man had to get them hot to pass the test, like running the engine at 5k rpm for 5mins. Previously I have replaced both O2 sensors for new Bosch items and this vastly improved the way the car drove. So these may need changing too. I think they were only about £80 each off eBay for Bosch ones. Quote Link to comment Share on other sites More sharing options...
Thediver Posted December 17, 2021 Author Report Share Posted December 17, 2021 Hello guys, Thank you for the replies! She sailed through emissions test with a new AOS and near side cat. Lamdas were fine eventually. 2 Quote Link to comment Share on other sites More sharing options...
dpg123 Posted December 17, 2021 Report Share Posted December 17, 2021 40 minutes ago, Thediver said: Hello guys, Thank you for the replies! She sailed through emissions test with a new AOS and near side cat. Lamdas were fine eventually. Don't forget to ask for your old Cat back from the garage as you can recover a decent chunk of cash selling them for their precious metals. https://catalyticrecycling.co.uk/ Quote Link to comment Share on other sites More sharing options...
Luciano casali Posted December 20, 2021 Report Share Posted December 20, 2021 My 3.2 did the same get the garage to put a rag in the exhaust pipe with the probe and this restricts the gases and the probe gives a better reading worked for me good luck Lou Quote Link to comment Share on other sites More sharing options...
Thediver Posted January 4, 2022 Author Report Share Posted January 4, 2022 On 12/20/2021 at 1:02 PM, Luciano casali said: My 3.2 did the same get the garage to put a rag in the exhaust pipe with the probe and this restricts the gases and the probe gives a better reading worked for me good luck Lou Good to know. My cat was knackered though as you could hear it rattling. @dpg123 I did not know that! I will check with the garage! Thanks a lot Quote Link to comment Share on other sites More sharing options...
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