My HC ppm is reading too high. I failed emissions. what does this mean?

Asked by kdubb Aug 23, 2012 at 02:21 PM about the 1991 Mazda MPV

Question type: Maintenance & Repair

Its reading 176 and the most allowed is 151

2 Answers

6,440

If your hydrocarbon is too high, I would suspect a faulty catalytic converter. But the only way to be sure is to have a shop thoroughly diagnose the issue.

61,115

HC's is running to rich, the number isnt high enough to say the cat is bad. Do a standard tune-up is it hasnt been done recently, new plugs, wires, cap, rotor, and air filter.

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