Honda failed CA emissions... any advice?

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Last year I took in my 90 Civic w/1.5 for smog and it barely passed. In the last couple months/5000 miles I've replaced the fuel filter, air filter, spark plugs, oxygen sensor, ignition wires, distributor, and PCV valve. The car does consume about half a quart of oil every 500 miles. I've been using Valvoline Maxlife 10w30. Car has about 250K miles. Took it in for smog again and it failed the sniffer. Everything else passed. The smog tech suggested replacing the catalytic converter. Any other tips/advice before I spend $200+ on a new cat? Thanks in advance!

Ed6Emissions-1.jpg
 
Did you take it out for some hard full throttle runs on the highway before you went in? The cat may well be poisoned by now with that oil usage. And the new cat my well get trashed soon and not work in a year. Good luck anyhow.
 
Maybe check and make sure the air pump is working? Dont know too much about Hondas, but the air pump is pretty important in making sure contaminants are burned up. EGR valve working? Take it in for testing with a fresh oil change and do a sea foam on the top end prior to the oil change?
 
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Quote:
90 Civic - MaxLife 10w-30 & Kreen w/Puro Classic

Did you do a smog test with Kreen in the oil?
That may have effected the gas analyzer readings.
 
Originally Posted By: Trav
Quote:
90 Civic - MaxLife 10w-30 & Kreen w/Puro Classic

Did you do a smog test with Kreen in the oil?
That may have effected the gas analyzer readings.


Actually I did... didn't even think about the Kreen being in there.
 
Your CO number would easily come into spec with a new catalytic converter. The HC numbers are very high and I am not sure that the cat is going to fix that. I would do a compression check to get a sense of whether your valves and piston rings are doing their job.

I agree that your cat is probably past it, but it is very likely time for an engine rebuild after a quarter of a million miles and 22 years on the road.

Where this is weird is that I would have expected higher oil consumption. Good luck.
 
Id say poisoned. Why? Because both your oxidation (CO and HC) and reduction(NOx) characteristics are high. Unless there is an oxidation state shuttle in the catalyst in there that is overcome, Id say you have a poisoning issue. Especially because of the parts that you have installed, which I assume yields no CEL?
 
If you want to keep this car you probably should rebuild the engine to fix the oil burn (most likely stuck ring and valve stem seal), then replace the cat (Walker has a CARB certified one that cost something in the range of $300-400).

Or you can sell it out of state and buy another one that pass smog locally.
 
I'd definetely look at the vacuum hoses for any leaks, and check the plugs to make sure they look good.
as for the NOx, I'd take the EGR valve off and soak the EGR valve and components/lines with carb spray and break that carbon up.

then I'd do 2 seafoam treatments and then throw a can of it in the gas as well.

Drive a hundred miles and then head back to the smog place.
 
Thanks for all the tips everyone. I did a vacuum leak test recently and it came up fine with no leaks detected. This particular motor doesn't have an EGR system, so no worries there. The plugs are only 5000 miles old and look good. I did a seafoam treatment through a vacuum line and tons of white smoke has been dumping out the rear. Haven't had a proper chance to drive the car to clear out the seafoam yet because I am at work.
 
I would change oil to get rid of the kreen, and run it to burn off any leftover seafoam.

for kicks I might replaced the Tstat if it hasn't be done recently.

if it still fails, yeah time for a new cat... its got almost a quart million miles. chances are its empty, like when i finally did the cat on our 1990 deville w/ 260,000 miles. The cat was empty except for a few pellets rolling around. It pass emissions after that.
 
Originally Posted By: teambeechstreet
I did a seafoam treatment through a vacuum line and tons of white smoke has been dumping out the rear. Haven't had a proper chance to drive the car to clear out the seafoam yet because I am at work.


Big mistake, seafoam is a cat killer, the worst thing you can use. The white cloud is pale oil which further contaminated your sensors and cat.
 
Originally Posted By: LeakySeals
Originally Posted By: teambeechstreet
I did a seafoam treatment through a vacuum line and tons of white smoke has been dumping out the rear. Haven't had a proper chance to drive the car to clear out the seafoam yet because I am at work.


Big mistake, seafoam is a cat killer, the worst thing you can use. The white cloud is pale oil which further contaminated your sensors and cat.

I'm going to replace the cat so I figured some seafoam before replacing the cat is no big deal.
 
Chevron Techron concentrate is what to use. Its the real deal Techron was developed specifically for better emissions and valve cleaning in a modern engine, unlike the motorboat tonic from 1930 you used. Has PEA, an additive which is modern chemistry. It takes time to clean stubborn carbon buildup. You put it in the tank and drive, no games. I would flood the car with that, they have specials, 2 for 10 bucks at AAP. After a few bottles the change is dramatic. No pale oil smoke shows, because actual carbon is hard to see. Techron got me passed after rejection, others too. Good luck whatever you decide!
 
Looks like it's going to be mostly cat that fixes it. CO and HC will definitely be cleaned up. NOx should clean up with a cat too but it may be close. You say it has no EGR, but it shows the EGR functional test as pass, not N/A. Are you sure it has no EGR?
 
Originally Posted By: Scott_Tucker
Looks like it's going to be mostly cat that fixes it. CO and HC will definitely be cleaned up. NOx should clean up with a cat too but it may be close. You say it has no EGR, but it shows the EGR functional test as pass, not N/A. Are you sure it has no EGR?

The results are on the left side, which shows N/A for both Visual EGR and Functional EGR. Only the automatic transmission models had EGR
 
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