CRG Discussion Forum
Camaro Research Group Discussion => General Discussion => Topic started by: stovebolt on February 11, 2010, 10:12:29 PM
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Hi. I would like to solicit comments from those of you that drive your cars with a stock, fully functional smog system. I've read that upon deceleration there can be a popping noise and back-firing. Is this correct in all cases and are there any other adverse effects? It's hard to imagine that this was acceptable. Thanks for any input.
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Hi. I would like to solicit comments from those of you that drive your cars with a stock, fully functional smog system. I've read that upon deceleration there can be a popping noise and back-firing. Is this correct in all cases and are there any other adverse effects? It's hard to imagine that this was acceptable. Thanks for any input.
"Popping" on decel/overrun is a classic symptom of a failed diaphragm in the diverter valve; when that diaphragm fails (and they all do after 20+ years), the valve defaults to full open, and air is pumped into the exhaust manifolds 100% of the time, causing the "popping" on overrun. The failed diaphragm also becomes a major vacuum leak through the signal hose from the carb to the diverter valve.
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The 67 system is much more problematic than the 68-9 system.