1995 Chevy Astro Van failed the smog test - When I left the smog place my vehicle started acting up.

My Chevy Astro Van 1995 failed the smog test. I took it to a test only as required by DMV and it failed. The vehicle was in perfect conditions, when I took it in no leaks or malfunctions were present. When the technician informed me of the failed test I took the paper work and drove off. Within seconds I noticed the van was shaking I took it immediately to a shop and they found a spark plug cable disconnected. And found my radiator leaking. Its a small amount of coolant that I found leaking, could the damaged been done by the technician? And could the unplugged spark plug have caused a:

A. Failed the emissions test due to high HC.

C. Failed the emissions test due to high NO.

I conducted a full inspection before I took it in and no cables were unplugged prior to taking it in and a oil change was conducted as well.

Answer:

We can't comment on whether the coolant leak was caused by the smog station. It is not likely. As far as the disconnected spark plug wire... That would have definitely caused high HC, but not high NOx. The high NO was probably caused due to high engine temperature (NO is created when the engine's internal combustion temperatures rise above 2500f) - the same problem which caused the coolant leak in the first place. We have to assume a pre-existing coolant problem caused the leak and the high NO failure. The disconnected sparkplug wire could have caused the high HC fault.

We'd recommend fixing the coolant leak problem, replacing the spark plug wire, and ensuring all plug wires are attached properly before the next smog check.

posted by SmogTips Support