Failed first attempt at emissions testing

Update: Passed!!


I tried for an emissions test today, but failed on 1 out of 4:

Loaded (HC = 277 / 400, CO = 2.35 / 3.75) - no problem
Idle (HC = 1038 / 400, CO = 1.31 / 5.00) - failed on HC. Note low CO.

I am hoping that someone might be able to give me some insight one what my next steps should be.

I have a 1974 304 V8 with Edelbrock 1406 carb, Edelbrock intake manifold (No EGR, MSD ignition, distributor & wires. The vehicle has sat for long periods of time.

Before the test:

- set the timing at 6 deg BTDC and confirmed that the total advance was acceptable. While setting the timing, I noticed that the TDC mark was rock steady under the light which I am assuming means the distributor is good.
- set up the 2 idle mixture screws on the carb as per instructions. Note: I ended up having the right hand one screwed in a bit more than the left hand which may be wrong as I have read that they should both be the same.
- Replaced the PCV valve.
- Replaced the air cleaner.
- Got fresh oil change.

However, I did not do anything with the plugs. Also, when I picked the vehicle up, the tank was full so it may be old gas....also not sure of the quality if the guy selling it to me had filled it up recently.

Based on the fact that the Idle HC are high, and the CO is low, that on idle, one or more cylinders are not firing efficiently. I am thinking that my next step will be to pull and replace all the plugs. Not sure if inspecting the old ones when I pull them will be usefull.

Any thoughts??

 

It's to lean. Richen it up to bring the HC down. My smog guys will take the time to adjust the carb rather than wasting their and the customers time.

 

If I lived where emmissions testing was required, I'd invest in a O2 sensor and gauge to tune with. They can be had for ~$30 to over $200. http://www.amazon.com/Intellitronix...BE/ref=sr_1_34?ie=UTF8&qid=1331083308&sr=8-34
Here's several to choose from. http://www.thedodgegarage.com/turbo_o2gauge.html

 

Ya but this whole emission testing is out of hand. All they do is test, fail, give you an enormous quote on repairs, retest, pass. Any good honest smog technician can see the hydro carbons are high at idle and the fuel is low. With room to spare cause he can go up to 5.00 all they need to do is turn out the mixture screws to smooth it out and the HC will go down. It's nothing but a racket to make shops money. But if that tech told me he had to adjust to screws to make it pass and not charge me? Guess where my business is going.

 

Depends on What the rules for emissions testing are in the area being tested. Here the testers are not allowed to do anything but test. They cannot work on the vehicles. Eliminates fraud issues.


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It's the same here but if it takes 5 minutes to adjust a screw they will do it rather than fail the vehicle, quote him, charge him a minimum and retest. Granted its easy money but to me it's not honest.

 

Just taking out the air cleaner for the test has passed a couple for me if its close. Wash state is finally phasing out the test cause it is gotten so rare for anything to fail it.

 

Here if you don't pass you don't get charged. Our testing is conducted by the state though vs independent shops.


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Agree with the above adjustments to the carb as well as the plugs. Do you have the AIR pump also? I wonder if a non-EGR manifold has anything to do with it as well? The 74 had EGR and AIR.

You might want to try to burn some of that gas out and add some fresh. Shouldn't take too long with a 304.

 

mehhHere it's been a struggle. Maricopa County makes me test EVERY YEAR and I usually fail 1-2 times before it passes. Now it's gotten to the point where the CJ is older than anyone doing the testing and usually they pull every guy in the facility with a few large manuals and all of them stare under my hood.....this all happens in July every year when its 115 degrees outside. I hate emissions testing. Big expense, waste of time, and at the end of the day I drive the vehicle less than 2K miles/year. Sigh.....

 

We have a 25 year and older exemption here in Georgia, and they only test in the metro areas like Atlanta. I guess they figure cars older than 25 years make up such a small portion of the vehicles on the road that it really doesn't matter.

 

Interesting thread, I checked the sensors on the link posted and all seem to be permanent instillations. Any that are portable and used like a test tool, tune and remove ?

 

Not really. You have to weld in a bung and then use a plug if you don't leave it in. Using then them at the tailpipe is inefficient. The only real way is to invest in a 4 gas analyzer. But those are not cheap. And unless it's your profession it's not a very good investment. I had one when I worked for the public but sold it when I went to work as a private fleet mechanic. In the last 20 yrs I wish I still had it about 3 times.

 

I bought new plugs today so will put them in and see if it makes a difference. The comments about the carb are right .... I suspect that I leaned it out to much on one side so at idle, I am not burning efficiently (i.e. low HC and low CO at the same time). This is my first time getting emissions done so I read up a lot on the internet and there was a lot of talk about leaning out the carbs a lot to pass. If it fails a second time, I have found a shop that can test it so I can have them adjust the carb to get on spec and then take it right into the test center which is not too far down the road.

 

Lucky for me, my CJ5 is a 1974 which puts it in a different category. It is exempt from the under hood inspection and the HC and CO specs are higher than 1975 onwards.

I agree that it is a waste of time to test vehicles like ours. Typically, they are not driven very much so the contribution to air quality is very small. I did read on one forum that Arizona is looking at going to a rolling start date so that every year, the exemption would advance. Not sure if that is true, but would be great....although if they start with 1967s, it will be a few years before mine becomes exempt.

Have you looked at getting historical vehicle insurance?? At 2K miles per year it probably qualifies and you would be exempt from emissions testing. That is not an option for me as I am a "winter visitor" so don't have an Arizona license which makes getting insurance a challenge.

 

Totally, but they won't cover any damage off-road. I built my jeep to use in the field hunting, fishing and general outdoors. The chances of damage occuring are just as great on and off road for my usage so the classic car insurance was a no deal.

 

ive heard a ball of steel wool jammed in the tailpipe right before the test will make it pass something with oxidation on the wool...... or just get it running right.... or move to rural Maine and skip the emission teat altogether

 

NC has no emissions test for vehicles 1995 and older!! This covers the CJ and YJ. My VW is exempt due to being a diesel. The only inspection the YJ needs is a yearly safety inspection, lights and such. The CJ is exempt from all inspections due to being older than 25 years.

 

Thank goodness for the "reasonableness test" in some states. Seems silly to me to apply emissions testing to a vehicle that is so old when, as a group, they make up such a small percentage of the vehicle population.

I hope you are able to resolve your emission testing issue.