Smog test Failed

[2mAn]

Nice! Congrats. Give us some details. Brand new Magnaflow CA legal cat? How many miles before you tested it, etc?

[CR325IS]

I got a brand new D.E.C Cat converter from Bavarian Autosport. Put in new Bosch plugs and a new air filter for the stock box, rode it for 50-60 miles took it in and passed. The numbers were significantly lower than the first test. I’ll attach a picture when I get a minute.

[RED87]

Not trying to thread jack or anything but I just got mine done the other day and they tested it at 0MPH and it passed no problem... is this normal ? also, all I did was drive from my house straight to the smog shop which is literally like a mile away... no extra driving or getting it hot...
plus, my paper looks a little different from yours... different max numbers and things like that..

[CR325IS]

They did mine at 15mph and 25mph. It’s probably different because I live in a different county.

[TheRob]

Thats the 2 speed idle test. Certain areas of California that have a less dense population aren't required to be run on a dyno or if the car has traction control that you can't disengage, or is AWD. You very rarely see a car fail a two speed idle test like this because no real load is placed on the vehicle.

Also CR325is glad it worked out for you without too much of a hassle.

[d_elson0]

Bump.
another failure here... coming back from TX for the last 7 years. Man it was nice to just have a “safety inspection”’only due to the car being over 25years old.
ill be using some of the tips here prior to just paying a shop to fix it. Lacking time as of right now.

[CR325IS]

Soooooo I had to test again this year and failed again....I changed my oil, fuel filter, oil filter, air filter run premium gas and rode a few miles on the freeway to get it nice and hot. My cat is two years old. I am going to look at the spark plugs tomorrow. Why the hell do I have to fail this every two years its so damn annoying. Any suggestions?
NO(PPM)
25MPH Max:724 AVE:272 MEAS: 1088

[randywalters]

Soooooo I had to test again this year and failed again....I changed my oil, fuel filter, oil filter, air filter run premium gas and rode a few miles on the freeway to get it nice and hot. My cat is two years old. I am going to look at the spark plugs tomorrow. Why the hell do I have to fail this every two years its so damn annoying. Any suggestions?

NO(PPM) 25MPH Max:724 AVE:272 MEAS: 1088

Wow that's a huge jump. IIRC, high NOx means the engine is running too lean for some reason (could simply be a bad temp or ox sensor etc).

I don't think it has anything to do with your Cat (HC is the Cat category).

Post a picture of the whole test results sheet so we can see all the other numbers. Maybe also include both the 2017 Fail and the 2018 Pass sheets within the same post so we can easily compare past and present numbers without having to scroll to the top of this thread and back down again.

[mtech325]

I had a similar issue not too long ago where my car didn't pass from high NOx even with new 1 year old cats. Afterwards, I did the usual tune up stuff, but I also used Mopar Combustion Chamber Cleaner to clean out some of the carbon buildup on the pistons. After the car was done with its smoke show (similar to seafoam), I proceeded to change the plugs and the o2 sensor (as it got fouled from the Mopar cleaner process), then took it in for smog again and it passed surprisingly easy. Not sure if it'll work in your case, but wanted to pass that info along.

[efficient]

California should just let these old cars be smog exempt.

[Mohit]

California should just let these old cars be smog exempt.

I thought cars over 25 years were exempt somehow because of some classic car thing. Is this not the case, or am I not reading it right?

[reelizmpro]

First of all, from my experience aftermarket cats do not react well to prolonged rich or lean mixtures. They aren't as robust as the OEM cat and will fail on you if you say run rich for 2 years (in time for the next smog check). You have to make sure your car is running perfectly stoichometric if you expect it to last. California unfortunately does not have a rolling exemption like most states. As the law stands, all cars 1976 and newer are required to have bi annual smog checks. Doesn't matter how old the car gets, if it was made after 76, it must be smogged. There's a push for a rolling 30 year exemption but who knows what will happen with that. I'm convinced CA just wants all ICE cars off the road in the future in a push towards electric vehicles.

[TheRob]

You probably need an oxygen sensor. You get what they call a "honeymoon" period with brand new converters where they will work really well and you might get lucky and pass even with things not working perfectly. Your O2 sensor has likely slowed down from age and thrown off your air-fuel ratio and the cat will not work right in this situation now that it's got some miles on it.

[CR325IS]

I passed. Changed out my Fuel filter, Changed oil/filter,new Valve cover gasket and adjusted the valves. I do not look forward to doing this in two years.

[bimmbo]

Failed in 1/2020 at 15 ppm for high HC (meas 163 ppm, limit 114) and was close to failing for high NO (meas 710 ppm, limit 785) . It was passing at 25 mph. Before the test I drove around for about 30 minutes relatively hard, but when I got there I had to wait about 15 minutes (with the car idling). During the inspection portion they turned my car off so it had ten minutes or so to cool off.

After the failed test, I ran Royal Purple fuel system cleaner through (split between 2 tanks), then ran another tank and a half of straight fuel through. Drove for about 30 minutes tring to basically keep the engine redlined during that drive. 2/2020, pulled into the smog shop and had to wait a few minutes to start the emissions test, so sat outside redlining the engine as much as I could until they pulled it on the tester. Passed this time: at 15 mph, HC meas 72 ppm, NO meas 130 ppm. 25 mph was the same as the first test.

I think it's worth a shot just getting the cats really hot and trying pass without doing a bunch of work.