914-6 Won't Pass Emission Test, (never does...*&$#@^$% bullshit) Options

[Eric_Shea]

I sent Rich some numbers via e-mail but I thought we should post here in case we have some answers that may help others. I just failed both HC and CO. Stock 2.0 six.

ASM Emmission Test

HC 15mph:
Max - 509
Avg. - 109
Meas - 573

HC 25mph:
Max - 469
Avg. - 89
Meas - 401

CO 15mph:
Max - 5.07
Avg. - 0.76
Meas - 10.17

CO 25mph:
Max - 4.97
Avg. - 0.77
Meas - 9.57

I doubt these guys even attempted a hand at the enrichment screws. I used to take it there all the time when the owner would actually wrench on cars (old P-car mechanic... not that old). Now it's just a bunch of melon heads with computers.

The guy took about 10 minutes to bring my car out and then said "sorry it took me so long... I didn't know how to start it" (IMG:style_emoticons/default/blink.gif)

So... lean it out and...?? (IMG:style_emoticons/default/confused24.gif)

I'm no good at this shit... thanks in advance.

[Eric_Shea]

OK... so far I've got too rich. Possibly advanced too much. Ix-Nay on the premium gas (unburned fuel creates HC's).

Anything else? (IMG:style_emoticons/default/confused24.gif)

[mightyohm]

Way too rich. Could also be misfiring.

[ArtechnikA]

just my off-the-top -- i hate trying to do this long-distance and with no measuring instruments...

i'd guess too-rich idles or the mixture screws too
far out, and too much initial spark advance. maybe run midgrade gas
instead of premium -- too-high octane gas can result in unburned
hydrocarbons -- there's a note to that effect in the MFI references...

i've heard that it helps to have it HOT before taking it in, maybe run through a can of from-the-Chevron-station Techron.

and of course this presumes stuff like your plug wires and spark plugs are up-to-snuff and the air filter is not clogged -- all that "is it plugged in" stuff ...

you can open the valve clearance a little bit - takes out a bit of cam overlap, but that's really a PITA on a /6 ...

maybe there's something to that add-a-gallon-of-alcohol theory...

[Cap'n Krusty]

Lean it out. At those numbers, it''s a cinch to run better. IMO, running premium in this engine will probably be OK, since it was made for it. The Cap'n

[Eric_Shea]

OK... no mis-fire. Plug wires are new. Carbs haven't been touched since the last time the same shop "PASSED" it.

However, I can lean it out a bit and get the Techron (Chevron right up the street). I just filled it so it should be fun running through the premium with outdated plates.

I haven't really gotten it out and cleaned it out so maybe I can get a permit and give it a good run, burn out the premium (along with a can of Techron) and start over.

Tell me more about Alcohol...

[lapuwali]

Rules of thumb: HC falls rich to lean. CO also falls rich to lean, but falls faster than HC. So, CO is more sensitive to mixture than HC. If NOx is being measured, it RISES from rich to lean, until you're fairly lean, then it falls again.

On a carb'd engine with no cat, I'd expect HC to be no higher than 250 or so, and CO should be around 3%, more or less. You're so far above those numbers I'd say you're indeed rich, and probably not by a huge amount. It's possible you're misfiring, but I'd expect you'd be able to hear it. You can probably correct this with the mixture screws alone. At worst, you may have to go down a size on the idle jets, but you can probably squeak it under with the screws. Note that if you lean it out so much it's misfiring at idle, HC numbers can go up again.

[Root_Werks]

Here in rainy WA, I have had the best luck filling the tank with 92 and chevron tech feul additive. Then go run the snot out of it get it nice and toasty warm.

When they ask you how many miles it has on it, tell them 250k. (Or just put a 2 in front of whatever your OD says. They give more allowance for cars with high miles on the OD.
Good luck, you will get it. (IMG:style_emoticons/default/biggrin.gif)

[Eric_Shea]

OK... so premium might be able to stay.

NO (PPM) 15mph
Max - 3219
Avg. - 1127
Meas. - 230

NO (PPM) 25mph
Max - 3019
Avg. - 951
Meas. - 213

So it looks like I can turn the ole screws in a turn (or so...)

[Eric_Shea]

What about Al-key-hall? Is it worth it? Does it do anything?

[ArtechnikA]

i'm not suggesting staying off premium forever, don't get me wrong - we're just talking about getting it through emissions testing.

short version: ethanol burns very cleanly, and it has fewer hydrocarbons per unit volume, so in addition to the clean-burning properties, it also tends to lean things out by giving you less fuel per gallon of fuel. also not a long-term solution :-)

hardware/paint-store denatured alcohol is about 90% ethanol with 10% methanol added to "denature" the ethanol and make it un-drinkable (quite toxic, in fact...)

[ edited -- left the 'm' off my 'm'ethanol the first time. i can spell but i can't type ... ]

[Jeff Bonanno]

10% methanol to denature. toxic. also, did you know that one antidote to methanol poisoning is ethanol?

[Jenny]

10% methanol to denature. toxic. also, did you know that one antidote to methanol poisoning is ethanol?

thank you, Tyler Durden. (IMG:style_emoticons/default/biggrin.gif)

Jen

[ArtechnikA]

10% methanol to denature.

i couldda sworn i hit that 'm' key.
thanks for bringing that error to my attention.
i did edit the original post just to eliminate any confusion...

[Eric_Shea]

i'm not suggesting staying off premium forever, don't get me wrong - we're just talking about getting it through emissions testing.

Understood... it sounded like I might still be able to get by with premium and have it pass though...

Here's the battle plan:

Tune Carbs Tomorrow - I'll check the enrichment screws and see about leaning them out. Sounds like it's way too rich. I'll pull them out 1.5 turns and maybe even go "in" from there. I'll go as far as hearing lean pop and then bring them back out accordingly. I'm at 4,500 ft. so lean is it...

Two Bottles of Techron - I'll pop up to the Chevron station tonight and grab those.

One Gallon of Alcohol - Not sure about this but it sounds like it may help it burn a bit cleaner and that can't hurt right now. I'll run through this tank and get it back to normal.

Sound good?

[MarkV]

High HC #'s are usually a ignition fault. With a CO of close to 10% you probably need to adjust the carb mixture screws.

I have had good luck raising the idle up to around 1100 RPM & running a set of platinum plugs for the test. Carbs have a dirty idle but your car is running dirty at cruise as well. CO should be around 3.25-3.5% & HC should be 100-150 PPM.

[echocanyons]

Eric,
Take it to Ed, he enabled my 74 with carbs to pass.

[Eric_Shea]

Ed's not available until the 15th. The bastard decided a "Vacation" was due RIGHT WHEN MY 6 NEEDED EMISSIONS TESTING! (how dare heeeeeeeeeeeeeeeee?) (IMG:style_emoticons/default/laugh.gif)

[Gint]

It's a PITA Eric. BTDT. 'Specially at altitude. I can't add much to what has already been said here. Except...

The hotter you can get it, the better off you'll be.

In addition, find out what the idle limit is and bring the idle up as high as you can. It helps bring the numbers down. High HC is why I bought the MSD for mine. If your ignition system is in good order, then retarding the timing *should* bring it back in line.