I just purchased a 1985 z28 with 305 H engine. The car is misserably failing the Emissions test here in missouri. Hc and Co levels are through the roof. The car runs great! I have replaced the o2 sensor, installed new exhaust system including the cat. Replaced all filters, chaged oil, pcv. After doing this the car fails worse. Local shop told me that he found charcole in the line that goes to the carburetor from the charcole cannister and that the cannister and a couple of check valves would need to be replaced at a cost of $350, but he is not sure if that will fix the problem. Has anyone had experience with this type of problem. Please help.

 

Check valves costing $350? What kind of crack is this guy on?

 

Something you might want to try. At Advance Auto saw some type of fuel additive that is "garrenteed "(spelling was never my strong point) to pass emissions. I dont know what is in it, what it does to engine or if it works but might be worth a try. In Virginia we have a visual check, so doesnt sell too good around here.

 

I tryed that stuff and still failed misserably.

 

Post the numbers from the emissions tests, including the requirements.

 

Thank you for all your responses. I replaced the vacuum control valve from the cannister and the carb. Cut the emissions in half and received a waiver.
Thanks again.

 

you need to replace the canister too, thats where the charcoal came from.
all the vacuum lines need to be blown out too. also don't be surprised if you need to have the carb rebuilt before too long, it probably has charcoal in it.
the canister probably had liquid fuel in it. normally the canister gets liquid fuel from overfilling the gas tank constantly, but a bad purge valve which is what you replaced can pull fuel from the tank into the canister too.


MKnight, auto repair at a shop isn't cheap, they have to make a profit, if they don't, then they go out of business.
$350.00 isn't too terribly bad for what he probably would have done, $30~40 for the purge valve, i don't remember what a new canister runs now, the last one i got a few years back was around $160.00 or so, 2 hours labor for replacing parts, blowing out the lines, adjusting the carb, probably a new fuel filter, it adds up quick.

 

As I have said before, these cars are 20 + years old, they are expensive toys. Be prepared to spend money and have a spare car you have access to.

 

Hey rideon200, I too live in Va, and am restoring a 1987 IROC. I have a chance to put a 355 in it but I'm worried about it passing emissions. Any suggestions??? Stone

 

On the charcoal can - if it were me, I'd grab one from the JY and try it - got nothing much to lose.

 

5-year-old thread, fellas...

 

Oooops!