Getting SC to pass "Basic Emissions Test"

[pryord]

I'm looking at purchasing a '79 SC with early style exhaust (no cat. converter). Can it be adjusted to pass a hydrocarbon and carbon monoxide test. The Oregon test analyzes car at idle for 30 sec. and at 2500 rpm for 30 sec. then idle for another 30 sec.

I know there are other posts on this, but I thought someone might have experience in Oregon.

Thanks,
David

[pbs911]

I don't know about Oregon, but dump some techron in the fuel tank and do some spirted driving to blow the gunk out. Also make sure the ingintion system is functioning properly: plugs, wires, cap and the timing is set correctly. When you test the car make sure it is fully warmed up and filled with premium gas.

Prior to the test, take the car to someone with a sniffer and lean out the fuel mixture. Also get the levels your car will be required to pass. Have the fuel misture adjusted to the required levels BEFORE you go to the smog station. As far as I know, there is no visual inspection in Oregon, but I don't know for sure.

[pryord]

I'll try what you've suggested. There is no visual inspection.
David

[nhromyak]

Actually, going aginst popular belief, if you run premium fuel you COULD get worse emissions. Remember 92 octane fuel has a SLOWER (relative to engine speed/compression ratio/ 89 octane fuel) flame front than 89 octane. That's the reason for running 92 octane in higher compression engines. It burns slower, no knock.

SO if you don't NEED 92 octane and you WANT to pass emissions, run good QUALITY, LOWER octane fuel!

Hopefully, you don't have carbon buildup in the P&C's.

Good luck!

[island911]

New spark plugs.

also, "oxygenated" fuels usally have more complete burning.

[Jdub]

You can replicate oxygenated fuel characteristics by dropping Heet or another alcohol-based water/fuel mixer into the gas tank. This is the stuff you see on the auto parts shelves that drives the water out of your gas tank.

John

[Tyson Schmidt]

Nhromyak is right. Lower octane fuel is easier to ignite. That's why high compression engines can knock with low octane fuel. The low octane fuel ignites from compression. Diesel effect. High octane fuel is less volatile, resisting compression-ignition. This is why lower octane fuel will give you lower emissions. Less unburned fuel out the tailpipe.

CIS can easily be adjusted lean enough to pass the sniffer, even without smog equipment installed. Provided, of course, that all is well with engine and state of tune.

[scedmonds]

I just had a smog test done on my '83 SC here in CA.

I've been updating the mechanical systems over the last two years, so was confident it would pass -- but noooooo.

My mechanic had to replace the spark plug wires ($225/set for original replacements) and the catalytic converter ($495).

The stock CA converter had NO baffles left in it. It was virtually a hollow tube, which translated into no back pressure and (of course) no catalytic conversion of the exhaust gases flying through.

Seems the previous owner ran the engine very rich, which led to the baffles burning up to zero.

My hope is you have a much less expensive journey to "smog blessing" in Oregon.

Cheers!

C.