Trouble Passing Emissions Testing

[Doms86Shortbed]

I have a 1986 Chevrolet C-10 2wd. The engine and transmission are not original to the truck. The truck has a 350 bored 0.030 over with headers, true duals with 2 catalytic converters, headers, an edelbrock intake, with a holley carb (not sure what model # it is but i was told it was a 600 cfm. The inspection sticker was good until october 2010 and because it's a daily driver and im only 17 I can't register the truck as a classic. In New Jersey if your car/truck is registered as a classic it does not need to be inspected. Long story short I went to get it inspection the first time just winging it expecting the worst and I passed all requirements except for the carbon monoxide output. The Hydrocarbons were good so i know all the gas is being burnt in the cylinder so i cant blame it on the timing. On the failed paper it said the truck put out 9.32...(parts per million?)% CO and the standard is 1.20%. So i changed the oil. Used CRC, new spark plugs, spark plug wires, premium fuel, and kinda tinkered with the holley carb. The second time around it turned out to be 4.6%. I then connected a vacuum gauge to the carb and tuned it correctly to the best of my abilities. If I fail this third time i'm going to at a loss for what to do next. I don't want to buy a carb or new catalytic converters if i dont have to because my part-time job budget is very tight and the truck is NOT very fuel efficient lol. If anyone has any trick or methods that they used to help their truck pass inspection please pass the info along to me. Also i want to thank everyone for all this knowledge about these style truck's ive always wanted one and now I finally have you.


             Thanks you everyone!,
                                        Dominic

[VileZambonie]

Is this a dyno test or idle speed test? It appears you are running very rich. Do you have your other results? You gave us CO but what about O2, HC, CO2 and NOX? If everything is correct try adjusting your air fuel ratio.

[Doms86Shortbed]

Okay guys I bought new rims and the guy was really digging my truck. We we're talking and I mentioned how I'm having difficulty passing the emissions part of the NJ DMV inspection. He swore on this that if I hooked a vacuum gauge up to my carb and tuned the fuel mixture screws until i got the most vacuum. Put CRC in the tank (both of which i previously did) and right outside of the inspection station turn back my timing until it was dogging really bad. Sure enough...bing bang boom brand new inspection sticker good thru 11/12. The guys really spent time revving the engine and doing their thing and when into the car the temp gauge was at 240. I just got into the parking lot and when i opened my hood the cap of the overflow tank blew right into the street. Gurgling and overflowing and all i could do was sit in my muggy truck in ice cold april rain waiting for enough pressure to get out of the radiator for me to take the cap off without burning myself. Well all in all. Dont leave the timing retarded for too long because you'll overheat but if your having trouble passing inspection this is true and I advise you all to try it!