Emissions

[Dustin27987]

My 1987 Buick Grand National has failed emissions three times, I gave the car a tune up (NewPlugs and Wires), changed the O2 sensor, the throttle position sensor and even put a new catalytic converter on it. It keeps failing on the Hydrocarbons though. Any suggestions?

 

[jimmymopower]

HCs are essentially unburnt fuel, so something in the system is causing it to not burn the fuel completely. What mods have you done? Stock injectors? Is the MAF meter working properly? What state are you in, do they test at highway speeds, ie. dyno? These cars should have no trouble passing if set up correctly, mine passed with no cat at all, 30lb injectors and a no-name chip...

 

[Dustin27987]

there are no mods done to the car. I live in Missouri. If my maf sensor wasn't working correctly wouldn't the check engine light come on?

 

[XLR8]

Not necessarily.
If you post all your emissions numbers in the emissions section, I'll bet gofstbuick can point you in the right direction.

 

[VadersV6]

Oil vapor will do major damage to hydrocarbons. Do you burn oil? I have enough blow by to fill a 1/4 cup capacity PCV catch can in 5-6 days. You should probably go get one of those as it can keep blowby from ending up in your exhaust when weak combustion at idle and a cold cat doesnt fully get rid of it. Or just plug the PCV, leave the breathers there and hope the guy doesnt notice the PCV isnt hooked up. Are you running a smog chip? Retarding the timing among some other tricks can bring emissions way down. Are you running a high flow cat? If so, those will barely control emissions at all. Only way it'll have a chance, is if you drive the car for awhile on the way to the station, and get the cat really really hot. Go WOT a few times and drive like a maniac. get that cat smoking. You should do this no matter what cat you have.