(Really, this only will make sense to CA owners...dunno if other states have emission requirements.)

So, just picked up a 1989 S-10 for a song...engine is running strong even thought it supposedly has 254k on it. No leaks, loads of power, smooth, no hiccups.

Problem is that I went to get it smogged today (haven't touched it otherwise) and it passed everything except for the Evap test that is required on vehicles older that 1995. Short version is they pressurize the Evaporative Control system (cannister?) and time how longs it takes to de-pressurize. It's a pass/fail thing, and the Test Only stations aren't supposed to give you any clues on how to fix it.

I know the most common is the gas cap, but this one looks pretty new with decent seals.

Wanted to see if any other CA owners have run into something similar and what it ended up being.

The hydrocarbons were a bit high (only a few points from failing) so I'll change out the plugs and see what the old ones look like.

Thanks in advance for the help,
-Roman

 

Eh. only ideas i have is where the evap can runs into the throttle body. the throttle body likes to get really carboned/gummed up in the hose passages. Remove the tb and clean it up.

for the plugs,make sure you buy ac delco or ngk. anything else seems to make problems worse.