Quote:
Originally Posted by jim_hoyland
I have a related situation and question. My last two CA smog tests were close to failing. The max HC at low rpm is 58ppm; both tests, one this year and another two years ago, showed my '98 low mileage Boxster at 57 ppm- too close for confortable.
This year I did the following as suggested on this forum: replaced spark plugs, ran two tanks with techron, and drove the car harder than normal. The car was hot upon delivery to the test station.
What might be the cause of the high HC measurements ? Is there a systematic approach to eliminating various causes ?
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Several things possible; dying cats will definitely do it, as will leaking injectors, or aging O2 sensors. Get the car scanned on a Porsche specific system like the Durametric used above, it will allow you to check the functions in real time.