I failed my emissions test yesterday.

I have a 92 LT1 with heads, cam, headers. I have Exotic Muscle long tubes with all the emissions hook ups and brand new RT cats.

My problem I believe is my cam. I don't think it is overly large. In fact it was specifically chosen so I could pass emissions.

The specs are 224/224, 114 LSA, .605/.605.

I failed the curb idle portion of the test. Max HC are 200 ppm. I tested 235 ppm. Trying his best to help, the tester even raised the idle speed to the allowable limit.

I still failed. I cannot drive the car without a pass.

Any suggestions???????

 

Have you tried running a gallon (to a full tank of gas)of denatured alcohol in it? Seems it works for lots of guys, but haven't tried it myself yet. I'll step aside and let the experts pipe in now

 

You are so close, run your fuel tank down to about 10 gallons, then add a gallon of denatured alcohol to the tank. Drive it around for a few minutes and then take the car through again. It should pass with flying colors. What was the CO levels? If they were very low it still should work well. You can get the alcohol at most paint stores, it is used as shellac thinner. Just BE SURE it is 100% denatured alcohol.

 

Good luck, and I feel your pain. I failed yesterday too. Mine was 319 PPM vs. 220 allowed.

I went there expecting to go through the full dyno cycle the car passed the last time. Instead they threw me a curve. No dyno, just the idle test. WTF!! That's the worst condition for a big cam, get off idle and it comes in to 14.5 A/F with good clean burn. At idle it's rich.

I have a long list of things to do with mine, and I have 90 days to get a free retest. If it still fails I have to spend $450.00 to get a waiver.

My list :
1. Put in fresh plugs, change the oil before going.
2. Get an Emissions tune file from Jeff Creech, which he promises at no cost to me. I'll have to arrange a way to flash the computer.
3. Actually No 1 for me but doesn't help you. Drop my exhaust and confirm that both my cats are still whole and functioning. I once got some good air on a country road and whacked the underside really hard. I may have a cat gone.
4 Save my tune file then go to Tony's Corvettes and spend at least $450.00 for tuning. FIgure out afterward whether I stay with that tune or flash the Jeff Creech tune back in. I like the way the car is running but it is certainly running rich. No help on the HC test at idle.

5. Move back to my hometown in upstate PA and forget this emissions testing crap. Save money on taxes to boot.

Have the authorities caught on to the way we are getting modded motors through the tests and are hitting us with the idle test that will fail with a big cam? Or is it just bad luck?

 

HCs (hydro carbons) are unburned fuel. They don't necessarily come from running either rich or lean. High HCs may result from a misfire or gasoline diluted in the oil (vapors enter the intake via the PCV) among other causes. The overlap of a cam can allow unburned fuel to pass directly to the exhaust. I don't know if alcohol is going to help with HCs or not.

RACE ON!!!

 

It depends on why the HCs are high whether the alky will work or not. I once got a 572 crate motor to pass emissions with 2 gallons of alky CO was 7% HCs were well over the limit. With one gallon the CO dropped by half, another gallon and some tweaking got it well into the passing zone.

 

My point with the alcohol, is that the CO you so easily controlled is a by product of combustion. The HCs are (unburned) not. If it works with the HCs, great. I guess I just don't understand why.

RACE ON!!!

 

That's what I love about having a distributor. My 89 Iroc had probs so I retarded the timing and it passed no prob.

 

PA emmissions is a joke... I passed last year with a hollow cat, and this year I was exempt. I love it

 

Alcohol acts as an oxygenator to gasoline. Alcohols chemical make up typically consists of more of hyrdogen and oxygen atoms. Gasoline on the other hand is what we all know as a complex hydrocarbon chain consisting of carbon and hydrogen only, with the exception of a couple additives which may hold a oxygen atom or two . Alcohol more or less acts as an oxygentor when added to the fuel. It thins out the hydrocarbons

 

My car will definitely be getting a dose of alcohol before the next try.

My timing is already retarded with this tune. But it's rich by both the visual of black carbon in my pipes and my personal sniffer.

 

My car will definitely be getting a dose of alcohol before the next try.

Please let us know the results. There are more than a few of us in the same boat or headed there.

 

I wish we could get some factual information on this alcohol trick, so far its been well I did it once, or I know a friend that did it, but what I would like to see is an actual photo copy of the failing reports then a copy of the passing report with alcohol.
Ill even host the pics for anyone that has this info.

 

in AZ - i use HEET (methanol) it's pretty pricey, but it SHOULD get you passed!

depending on the size of your gas tank - on my 22 GAL tank on my truck, i use 1/4 tank and 9- 12 oz. bottles of heet - passes with flying colors on both idle and loaded test!

i have used this trick whether i failed or not - it 99.9% of the time guarantees me a pass on the first try!
the one time i didn't pass i had a bad gas cap (wasn't holding pressure) so i had to completely retest ALL the functions again!

make sure as soon as you are handed your "pass" slip you go to the gas station and dilute it out with a top off of gas!

if you say methanol is bad for the "system" look around in the forced induction forums - those guys are using it to help cool down the A/F mixture upon entering the cylinders - so if it's good enough for them, it's good enough for you! - and BTW, i have been doing this since i started driving - 18 years ago! so IT WORKS!

 

i usually KEEP ALL my test reports, if i can remember, i'll get home and get scans of each - this was for my truck however, but it should be a little "picture" proof - we'll see!

 

I'll do that, but first I have to respond to the crisis in the only rational manner. ROAD TRIP!!!

I'll work on this and my continuing clutch hydraulic leak problems after I get a week of vacation and driving this beast!! PA two lanes here I come.

 

Thanks for all the suggestions guys. I will try the denatured alcohol first and then let you know.

tjwong,

My CO% was:

25mph test - limit 0.32 - reading 0.02

idle test - limit 1.00 - reading 0.49

My NO ppm was:

25 mph test - limit 421 - reading 419

 

I just barely passed AZ emissions last month and Trevor at Exotic Muscle told me next time, go out by Manzanita Speedway and put in a few gallons of methanol. It should pass easily and do no harm to the motor or sensors.

 

I was responsible for trying to tune this car when it was in BG for the engine mofications at TEA. The wider lobe seperation of the cam makes it sound very mild, it doesn't have the lope to it that my hot cam does. I would imagine that would make it pass more easily.

We got the driveability very good and the wide open throttle is dead on. If I remember right though the guy doing the actual modifications had me tune it very lean at idle, way to lean for my taste. He wanted to "ensure that it would pass emissions." I told him that running too lean would fail just as quickly as running too rich but he didn't believe me. I tuned it the way he asked since he was the one paying my bill.

I've talked with the owner of the car before and he said it can tend to have a rotten egg smell at times. The guy who did the works said it was no problem and it would "burn off." My experience has been that the rotten egg smell is another indication of it running too lean.

I'm thinking tweaking the VE at low RPM's may be all that is needed to pull it into line. What do you guys think?

 

Nathan, my car has the rotten egg smell at idle in traffic and when I idle in my driveway after a good run. You say that indicates too lean?? I've experienced the sulfur smell from the cat of my 4x4 as I start up a trail in Colorado, and it's the normal burn off of a cat. I always thought that was a cat carboned up from running too easy and too rich.

I do know that the inside of my header collector and the back end of my exhaust are very carboned up, but that's not necessarily from idle running.