Stupid Emissions Question...

[wahoo23]

I'm a newbie to the classic car arena with my 'new' '67 coupe w/ a 302, so I will apologize in advance. Today, my car failed emissions with a 1033 measurement for Hydrocarbons at idle. Limit is 1000. Just missed. What's my quickest/easiest/cheapest course of action, keeping in mind that this car will only need to pass one time for as long as I own it? Carb adjustment? Although I cannot be sure, wires look new, so I would assume that plugs are not that old either.

 

[ron67fb]

HC is unburned fuel, which means something is preventing full combustion such as a misfire, or something is soaking up fuel i.e. carbon deposits. What's the CO reading? When I last smogged my cammed and modified 289 I passed with ~700ppm HC. A few things that can clean up HC: long, hot drive, oil change, clean plugs, and hotter thermostat. A carb adjust might help if the CO reading is high, meaning the engine is running so rich it's misfiring. A carb adjusted too lean will also cause the HC to shoot up because of a lean misfire.

 

[wahoo23]

HC is unburned fuel, which means something is preventing full combustion such as a misfire, or something is soaking up fuel i.e. carbon deposits. What's the CO reading? When I last smogged my cammed and modified 289 I passed with ~700ppm HC. A few things that can clean up HC: long, hot drive, oil change, clean plugs, and hotter thermostat. A carb adjust might help if the CO reading is high, meaning the engine is running so rich it's misfiring. A carb adjusted too lean will also cause the HC to shoot up because of a lean misfire.

I actually drove 45 minutes to the testing site and that didn't seem to help. The CO reading was 3.49 at 2500rpm and 0.59 at idle, limit is 5.50. So it sounds like a carb adjustment is not the answer. So the best idea here is to do plugs, wires and thermostat? Is the thermostat tough to get to (I haven't looked)? Will the thermostat be marked, so I know what I'm getting is a hotter one?

 

[JDS68Stang]

Ok this is kinda funny because my GF was just telling me today about a nutjob on a Yorkie dog site talking about how her car failed an emmisions test.

She said she prayed and asked God to help her out, she went to the auto store and bought some additive and also put high octane gas in her car, she then took the car and w/Gods help she passed the emmissions test after, LMAO.

OK, yea that lady was nuts, but maybe high octane might actually help, I really don't know? You could run most all your gas out and then try $25. worth. Also the auto store might have an additive that will get you thru the test, again I don't know but you might wanna stop in one and ask the guys about it.

My GF's sleeping so I can't ask her what additive that nut used.

If this crazy ladies method works for this guy, it's gonna make you motorheads here look pretty bad!!!!,LMAO

 

[Rusty67]

Along with the plugs/wires, you might also want to change the cap/rotor on the distributor.

Edit:
67s didn't come with 302s they came with 289s. Are you sure that is a 302 in there ?

 

[wahoo23]

Along with the plugs/wires, you might also want to change the cap/rotor on the distributor.

Edit:
67s didn't come with 302s they came with 289s. Are you sure that is a 302 in there ?

Yes, it's not the original motor.

 

[jeffnoel]

Were are you located?

 

[wahoo23]

Were are you located?

Denver.

 

[ron67fb]

That CO is pretty good for idle. HC readings that high with low CO points to a misfire. Do you hear it misfire at all at idle? Even one hiccuping cylinder will cause problems. Could be a too-lean idle mixture, worn plug(s) with oversized gaps, vacuum leak, or plug wire shorting out.

Higher octane won't do anything beneficial, but there are additives out there that claim it will help the car pass smog.

If you're only failing by 33ppm then tune-up parts may save you. 1000 at idle is eye-watering, brain cell-killing specs and points to a dead cylinder. As a rough comparison, my 289 put out about 500 at idle when it was stock, and I've seen 5.0 EFI engines with no cats idle at 150ppm.

Search Stangnet for 'hydrocarbon', especially the 5.0 tech forum.

 

[Platonic Solid]

I'm a newbie to the classic car arena with my 'new' '67 coupe w/ a 302, so I will apologize in advance. Today, my car failed emissions with a 1033 measurement for Hydrocarbons at idle. Limit is 1000. Just missed. What's my quickest/easiest/cheapest course of action, keeping in mind that this car will only need to pass one time for as long as I own it? Carb adjustment? Although I cannot be sure, wires look new, so I would assume that plugs are not that old either.

Long ago when emissions testing was required on my 72 (302), it always failed. Until I started turning both carb screws "In" about a half turn (the car barely idled, but didn't stall) right before the test, then turned them back out right after the test. Worked every time.

 

[rbohm]

first torque the intake to make sure you dont have any vacuum leaks. next set your timing between 10 and 14 degrees. adjust your idle mixture to where you have the highest vacuum reading you can get. run the idle speed up to around 950 rpm. and add three gallons of E85 to the tank. the alcohol wont read on the emissions sensors as it burns too cold.

 

[SoCalCruising]

Tricksy.

 

[JDS68Stang]

OK, looks like you got some decent answers so far. I think rbohm's suggestion should get you thru the "cheapest" as that's what you wanted to do.
ron67fb also says he's heard of the additives that are supposed to help get you thru as well so check that out since your that close to passing.

After you pass I would still take the direction of these other posts when you have time and tune the engine to optimum performance though.

Hope you guys have as sence of humor about the crazy nut making you motorheads look bad, just a joke. My GF says now the woman put two bottles of injector cleaner in her tank w/ the high octane and that's how she got thru.

 

[LONN17]

G2P

CRC makes a product called Garunteed 2 Pass (G2P). Available at most auto parts stores.

 

[zookeeper]

OK, looks like you got some decent answers so far. I think rbohm's suggestion should get you thru the "cheapest" as that's what you wanted to do.
ron67fb also says he's heard of the additives that are supposed to help get you thru as well so check that out since your that close to passing.

After you pass I would still take the direction of these other posts when you have time and tune the engine to optimum performance though.

Hope you guys have as sence of humor about the crazy nut making you motorheads look bad, just a joke. My GF says now the woman put two bottles of injector cleaner in her tank w/ the high octane and that's how she got thru.

Most injector cleaner I've seen is made from methanol, which is why it burned cleaner. But if you want a long-term solution, I'd install a Pertronix ignition with the coil as well. I have one in my '68 and stock points in my wife's '69 Corvette. It really burns my eyes to run the Corvette in the garage for more than a few seconds, while the Mustang burns MUCH cleaner, despite the fact it has a pair of Holley four barrels for carbs. I know you're looking for a quickie fix just to get it to pass for now, but swapping to a modern igniton will get you better mileage and easier starts as well.

 

[Sicarius428]

MSD might help to burn things out a tad. Worked on my friend's car quite well. Change the plugs, cap, rotor and wires. Retard the timing to 8*. You can also run regular which will cause more detonation/hotter burn. You can lean out the carb a little... That should do it for only 33 points.
Kevin

 

[reenmachine]

next set your timing between 10 and 14 degrees. adjust your idle mixture to where you have the highest vacuum reading you can get. run the idle speed up to around 950 rpm.

Having been through this recently this is the advice I was going to post. Is there a "lopey" can in your 302? This can cause just enough inefficient combustion at idle to cause you to fail HC. Since you're so close I would wager that advancing the timing and turning up the idle will get you there.

For reference, in AZ I had a '67 with a fuel injected 345 hp GT40 5.0L fail HCs at idle. Anywhere above idle the thing blew clean and up on the cam is blew practically nothing. It's that B cam in there that made it fail at idle even when everything was working perfectly.

 

[67efivert]

actually id have to disagree i used to do emissions testing here in nc and if u retard the timing it will actually burn cleaner run like crap but it will pass id bet if u turned ur timing down to bout 3-4 degrees it would pass ive seen as much as 300 ppm hc drop from retarded timing

 

[TD68302]

Are you sure that you need a e-test, I have not needed to test my '68. Im in denver and using the 5 year collector plates. Might check into it, I don't think you need the E-test because of age.

 

[TD68302]

Anyways sweet looking ride