|
I had a 93 Suburban K2500 with a 454 and one time I took it to smog (in california) and it passed, but barely. I don't remember if it was hydrocarbons or nox, but the limit was around 980 ppm and my truck passed with 977 ppm. Just barely passing.
So the next time, 2 years later, I did a few things before I took it to the smog inspection.
I bought a can of seafoam and poured half the can into the crankcase and with the engine idleing I poured, just fast enough for the engine to stumble, the other half down the throttle body. Then I turned the engine off and let the truck sit over night. The next day I would put a new air filter in and drive the truck for a half hour on the freeway. After the drive I would change the oil and take it to the emmissions test.
Every 2 years I would do the same thing and the test results would get a little better each time. I would also change the plugs, wires, cap and rotor every 5 or 6 years.
I think the Seafoam helped but I'm not positive it did. I wanted the Seafoam to get into the catalytic converter and soak.
|