Help passing emissions

[phxboy]

Any help passing emissions. This is the first time I've had to emissions my 69 Chevy. Its a 350. It runs good and does't smoke. I failed the emissions test. The hydrocarbons were almost twice as much as the standard allowed and the carbon monoxide was also nearly twice as much as the standard allowed. Any suggestions would be appreciated. Thanks

[hjalbert]

not surei just moved to phoenix, andi am just planning on keeping my trucks registered out of state for as long as possible, what all do you have? i think the best way would be to A)disconnect the exhaust so it doesnt get to the machine hehe.

[Stout72]

Wow, I'm surprised! I thought California was tough. 1973 and earlier vehicles are smog exempt.

Simplest thing to do would be a tuneup. Even though your truck is running good, try at least changing the oil, plugs, wires, air cleaner, you know, all the basics. Check the timing. Don't know what ignition you're running.

[busterwivell]

I went thru that with a rebuilt engine in my 71. I told the engine builder it wasn't right. Sure enough, it failed miserably. Had a dead cylinder. You can get an idea what needs to be done by having one of those emmission service garages diagnose the problem. It will get you started in the right direction. And, yes, in AZ, we have to emission everything 67 and newer.

[Michael A. K. G]

Originally posted by phxboy
Any help passing emissions.

Gas-X does wonders.

Assuming the high HC is at idle, you can try adjusting your idle mixture. It sounds like you may be rich. And check the gaps of all the spark plugs.

I've had really bad experiences with national smog sniff chains giving incorrect results after happily charging $80/hour for diagnosis. I'd go to a mechanic you know or trust. Many have sniffers.

In California, you can request a cheaper "pre-test" if you think you might fail. Some folks will do a really quick'n'dirty one for free (basically, cram the sniffer in the exhaust and hit the button to get quick idle measurements).

[truckster]

CO being too high is usually caused by running too rich. You can look at things like the idle mixture, your float level, etc.

HC being too high is usually caused by incomplete combustion. Look for fouled plugs, any kind of engine miss, etc.

Also look for any vacuum leaks.

If you still can't pass, denatured alchohol will clean your emissions up (20-25% mixture). I would look into the other things first, though.

[LeRoy]

No checks in my county but I heard that the longer you sit waiting for the inspection the more the motor loads up. Best to take a trip down the highway at high Rev's, alot of in town driving also hurts. Jump on the throttle heavy a few times while doing the freeway thing then drop immediately into the smog shop.

[XXL]

Everything Michael A. K. G said and... run the truck up and down the highway pretty hard just before you take the test. You want everything nice and hot. And you can also go up one or two heat ranges on the spark plugs. Don't run those plugs all the time, just for the test.

I'd avoid the alcohol though. It will do as truckster says but it'll also suck up every droplet of water it can get hold of, which means you'll can get water in your fuel system, which is bad

Good luck,

Kenneth

[Michael A. K. G]

I don't know if I'd use hot spark plugs.

Too hot, and you may ping, which will really screw up your emissions. Plus, if they sniff for NOx, it will go up with temperature. Some sniffers check NOx, some don't. Depends on locale.

If you have the timing advanced, put it back at stock. Especially, if you have disabled emissions (this is illegal), make them work. Especially the AIR if your truck came with one.

[Jmac05]

There are several different over the counter things you can get that offer guarantees. I live in California, so I don't have to worry. Register it through a friend in Ca.

[Protrucks]

Convert it to Propane collect your conversion cost from the Feds and CA. Then switch it back until the next test.

[Low67C10]

I dont know what kind of test they have, 2 speed unloaded, IM/240 or acceleration simulation, but either way failing COs means the carb aint right. Get the carb fixed/dailed in and theres a good possibility that the HC will clean itself up. If it doesnt, check compression and if its good, do a ignition tune up(plugs,wire, cap and rotor).FYI, I do smogs in california and Ive heard we might have to go back to the 65-up cutoff like before.

[mikep]

I actually make a point of filling up about once every couple of months at the cheapass AM/PM minute mart just beacuase they use 10% ethanol in their gas. I use their hi grade "gas" and the truck doesnt really run any different but it gets the water out of my fuel system. I'd rather have the water flushed out of the tank on a regular basis than having it collect on the bottom of the tank and rusting its way out.