<VV> Emissions lights...

[Jim Burkhard]

They are not sniffing the tank, nor checking for additives. They are 
hooking up a gizmo that checks for (tiny) leaks in the evaporative 
emissions system (including the gas cap as Harry mentioned). The evap 
emissions system is the whole shabang that connects one or more carbon 
canisters to the tank to collect evaporative emissions and provides 
for onboard refueling vapor recovery.

Jim Burkhard


J R Read_HML wrote:
> I JUST returned from emissions test (IL) on an '01 Blazer.  The first 
> thing they do is put a sniffer in the gas tank.  I suspect that they are 
> looking for any additives which might get a marginal car past the test?  
> Next, they turn off the engine, hook up the diagnostic electronics and 
> restart - watching for the appropriate lights to come on and then go off 
> during startup.
> 
> Passed - good for 2 years.
> 
> Later, JR