Passed smog test by 1 ppm

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Lyman

Lyman

Joined
Aug 13, 2011
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Lakeside, CA
So I had my car smogged today as i have to do every two years here in Ca. I almost failed the 15 mph test. Max is 51 ppm HC and my car blew a 50 ppm. Everything else was fine. My car just turned 160,000 miles. I changed the oil and ran the car on the freeway for 20 minutes before the test. Plugs are two years old, I should have changed them and maybe a set of wires too.
What are your ideas as how to clean this car up? Does it sound like it just needs a tune up or what? Maybe some 02 sensors? Check for air leaks? Im dumb when it comes to diagnosing these smog test results.
 
Is the car bone stock? Check the tube from the exhaust manifold to the EGR and see how plugged it is. I had a 98GT that would regularly blow 0's on the smog test with mods.
 
Originally Posted By: bdcardinal
Is the car bone stock? Check the tube from the exhaust manifold to the EGR and see how plugged it is. I had a 98GT that would regularly blow 0's on the smog test with mods.

That tube being plugged would cause the high HC at 15 mph? It ran cleaner at 25 mph.
 
Originally Posted By: Blkstanger
No cels since I have owned it. I was thinking o2 sensors too.

The pre cat/af o2 sensor is a common cause for the catalyst efficiency CEL, worth replacing.

If you can get the cat off dunk it in laundry detergent overnight, high pressure water spray it off in the morning.

If its burning oil find a way to slow it down.

Prior to cleaning the cat or replacing the pre cat o2 sensor, clean the TB and give it a brake line booster blast of techron concentrate. Add some to the tank too.
 
Originally Posted By: LeakySeals
Originally Posted By: Blkstanger
No cels since I have owned it. I was thinking o2 sensors too.

The pre cat/af o2 sensor is a common cause for the catalyst efficiency CEL, worth replacing.

If you can get the cat off dunk it in laundry detergent overnight, high pressure water spray it off in the morning.

If its burning oil find a way to slow it down.

Prior to cleaning the cat or replacing the pre cat o2 sensor, clean the TB and give it a brake line booster blast of techron concentrate. Add some to the tank too.

It's not burning oil. I might have to top off a half qt in 5-6 k miles. And I DON"T have a CEL.
 
So glad no smog testing here, the R/T neon the gf drives has no cat no muffler egr blocked mopar ecu and lots more lol.
 
I read on here that the red line fuel system cleaner helped someone with a lexus improve his tailpipe emissions.
 
OK. Cats don't last forever, I suspect its about had it. I would try the suggestions, see what happens. Back in 97 the ECU catalyst efficiency programming was very low. Why you could fail the smog, but not see a catalyst efficiency CEL. Today its reversed. Newer vehicles catalyst efficiency is set really high, usually 95%. way higher than the actual state smog test. Why you hear about more cats going out sooner, and why aftermarket cats fail so fast. Its just the catalyst efficiency CEL "warning light" AKA P0420/P0430. Your lucky, you don't have to replace a perfectly good cat because the programmed catalyst efficiency threshold is set much higher than the state smog test, and get failed for a "warning light" CEL on a perfectly good cat.
 
I am in the exact same boat. My CAT is dying due to a failed oxygen sensor a couple of years back. I also passed by 1 PPM.

I am sure it will fail at the end of 2013.

I am thinking of using that "guaranteed to pass" stuff that O'Reilley sells, but that might be $40.00 wasted. Mike's Mufflers in El Monte say a new cat installed costs about $350.00 + one hour of my time.

The local Toyota stealership told me that the job will take a couple of days and cost $4,000.00! Of course they also told me that the transmission needed replacing 100,000 miles ago. The transmission has not quit yet.

What do you suggest?
 
If the cats are reaching end of life, you just might be able to stretch them a little longer with some header wrap. A little extra heat can give just the boost you need and because you're making them actually work better for real there's no guilt unlike with some "tricks."
 
I haven't seen CATs for sale for this car in a while. The last time I did they were over $1,000 at the cheap place. They have to be the Ca CATs. 49 state CATs won't do.
 
Originally Posted By: Cristobal
I am in the exact same boat. My CAT is dying due to a failed oxygen sensor a couple of years back. I also passed by 1 PPM.

I am sure it will fail at the end of 2013.

I am thinking of using that "guaranteed to pass" stuff that O'Reilley sells, but that might be $40.00 wasted. Mike's Mufflers in El Monte say a new cat installed costs about $350.00 + one hour of my time.

The local Toyota stealership told me that the job will take a couple of days and cost $4,000.00! Of course they also told me that the transmission needed replacing 100,000 miles ago. The transmission has not quit yet.

What do you suggest?

Read my suggestions above. and this http://www.bobistheoilguy.com/forums/ubb...764#Post2702764
 
Last edited:
Originally Posted By: dave1251
I failed a test in 04 on my 97 stang. The bad part I actually passed emissions but had a CEL. Of course had a bad 02 sensor.
That is the part that [censored] me off. You can have a clean running car and still fail. The persons that wrote the smog laws need an [censored] kickin.
 
Call Mike's Muffler in El Monte. See what he can do. I know it's a drive but maybe he can get one for less if you have an excuse to come up here. This assumes that your CAT is the trouble source. He might know of a good shop down there where you live. Let me know if any results. 626 443 5139 is Mike's Muffler's #. I have no affiliation with that shop.
 
After a little research I found that my car has six CATs on it. Three on each side. $1,000 is the cheapest I found online. In the future I plan on buying some o2 sensors, Plugs and wires and clean the EGR tube and MAF/throttle body. Next time it's due for smog I will have it sniffed early and see what happens before I shell out that kind of money.
A buddy of mine has aftermarket CATs on his Cobra and it passed smog. Only because the tech was to lazy to get under the car to look.
 
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