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Forum > Failed Smog Test > Question

chevy S10 pick up 1995 exstended cab 2.2 fuel injection engine

my truck the smog check,every thing passed except the hc ppm max allowed 40 mines 45.I look at vacum hoses for cracks an leaks,I found the hose lead from thr manafold to the pcv valve was hard and cracked at the end conected to the valve.I change the valve and hose.do you think that could have solve th e problem for me are if theres could be somthing else. thanks.
Answer:

Yes, a cracked PCV hose and/or defective PCV valve can absolutely cause high HC. The PCV system returns corrosive gases from the engine crankcase back to the combustion chamber where they are burned alongside the regular fuel & air mixture. It is important to ensure the PCV system is clean, connected and not leaking; otherwise air flow to the intake manifold and subsequently the combustion chambers can be altered. A PCV vacuum leak may cause additional unmetered air to enter the intake manifold causing a lean fuel mixture resulting in a lean misfire. A lean misfire would be seen through your Chevy S10's exhaust as high HC. posted by SmogTips Support

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