Just Failed Smog in Virginia

jonroe

Registered User
Dammit!

Just came from the treadmill test and failed. They test at 15mph and at 25mph. HC and CO passed fine on both. NOx barely passed at 25mph and failed by 3 lousy ppm out of about 870 at 15 mph!

Any great suggestions? By the way it is 98 degrees and very humid here today. I decided to turn OFF my manual cooling fan switch for the test and let the EEC cycle the fan during the test.

Plugs and wires are new, O2 sensors are nearly new, new MAC cold air intake, Borla cat-back exhaust, custom exhaust up front with supposedly new hi-flo cats.

I replaced the 3-cat staock system with two cats. The technician thought it could be the cats. He also said the weather was LOUSY for the test today - hottest day of the summer so far.

Could it be poor cats? Could it be cats too far back? The new front end exhaust moved them back beside the tranny and straigtened out the curves. Something else in the engine? It runs GREAT at all speed including idle and WOT.

I'm pissed! Any suggestions would be helpful. I have to get it fixed in August or I can't register.

Jon
 
mine was cats

I replaced cats with better ones and passed 35% cleaner a major improvement if your going to replace cats make sure you get straight flow and not our 90 deg bend cats. mine are larger and straight shot . it cost me $150 to replace down tubes and cats larger down tubes and cats.
 
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Nox is from (it actually forms at high tempratures) high combustion tempratures, the 98* outside didn't help at all, also If you let your fan run it would also lower your tempratures a bit. this alone might drop your NOX into the acceptable range. does your car have EGR? a malfuntioning EGR also causes high NOX (exhaust gas recirculation provided cooler combustion)
 
Manny,

I thought I had new cats, Feb 2002, but maybe they are no good. I did replace the stock down tubes with new smooth curve custom 2 1/4 pipes which moved the "new" cats back a little.

Rancher,

Yes, it was a lousy day but I wanted to get the test done well in advance of renewal on 8/31. There aren't many cool days here this time of year! I was torn about leaving the fan on because I have also heard that you need the car fully heated up to pass and that too cool cars can fail as well. So, at the last minute I decided to turn it off. This car does not have the EGR.

I could wait for a cooler day, leave the fan run and try again but I don't have much time to waste to get passed by the end of August.

Jon
 
I've heard of running alcohol in your gas before the test
since it burns cleaner. like a bottle of water remover.

Haven't done this myself but have heard of it. Any comments
on this anyone? Will it hurt cats if installed??

j. :eek:
 
Jon
My 90 did the same thing in California about 2 months ago. NOx just was a little out of range. Mine has stock (orginal) cats and about 160,000 miles. No EGR on 90 automatic. Mine also had new plugs, wires, O2 sensors installed prior to test. (I installed all that stuff just cuz I had half the engine apart doing the damper.)
Do not know if this will help you but it is not expensive to try.
This is what I did which got me into proper range.

Drained coolant and installed a 50/50 water & antifreeze mix. I also added one bottle of waterwetter (PepBoys). (I had heard and read that it would lower temp by 25 deg with that mix. I also did my own test with a mechanical gauge installed in place of the dash sender. The mixture did exactly that. It tells you how to mix on bottle.)
I than changed engine oil & filter. (Do this last just before going for test)
I added a bottle of octane booster to the fuel.

Don't know if this will help you, but it bought me some time to find a replacement engine to build. The coupe is running great but with 160,000 + miles I want to have an engine ready when I need one.

Good luck
Denny
 
Denny,

Thanks for the good suggestions.

My coolant is a little old (about 18 months). I have been meaning to get the water wetter but was waiting until early fall to do the coolant change.

The oil and filter are very new (a few hundred miles) using Mobil 1 5W-30 and Motorcraft FL-400S filter. I could try the octane booster. Does that tend to cool combustion?

So, should I or should I not have the cooling fan running during the entire test? I gambled and turned it off this time with the EEC cycling it on and off during the test (near 222 degrees). Somehow the combustion temps have to go down a little to get the NOx down unless it is a problem with my cats.

I think my engine is good and strong at 119,000 miles - I'm looking to keep it a long while. Don't think there is a need to rebuild it yet.

SCfalcon,

I did buy a bottle of STP complete fuel system cleaner yesterday. Maybe that will help a little. Excess carbon in the cylinder could be causing the combustion temps to be too high.

Does anyone know if weak cats can make NOx too high? I thought they mainly helped with HC and CO.

Also, my next test will be first thing in the morning with outside temps maybe 25 degrees cooler than the other day.

Thanks.

Jon
 
fan should be off

the nox levels are cats maybe your exh is to cool if cats are farther down than stock + there is a product called emissions pass it cleans up emissions alot but makes car run bad under power so do it on a low tank so you can burn it up fast and put good gas in as soon as possible.
 
Manny,

So you say keep the fan in normal EEC cycling mode rather than on all the time during the test? That's where I'm pulled both ways. I can see that having it on keeps the engine cooler and maybe keeps the combustion temps down a little but you also want the cats hot so they operate at maximum. With my cats farther back than stock I should try to make sure they are hot.

I'm taking it in today to the exhaust shop that built my exhaust and probably have new known cats put in. I hope that does it.

I also dropped a bottle of the "CD-2 Emissions Pass" gunk and a bottle of octane boost in the tank yesterday to run that through.

Jon
 
If you have a tuner try running slightly rich. This will lower combustion temps and send more HCs to the cats heating them up more.

Also leave the fan on, as long as your themostat is not too low, the engine will be warm enough to keep the HCs under control. A small change in temp could bring your NOx down significantly.

Aaron
 
See, I'm still confused about leaving the fan on. I've had mixed input here although I welcome all the suggestions.

Unfortunately, I don't have a tuner. I was thinking this morning that if I have a slight vaccuum leak that could cause the mixture to be too lean leading to higher combustion temps. I think I have a very slight vaccuum leak at the lower IC tube to IC connection that shows itself only when cold idling. It seems to idle perfect when warm. It used to be worse but I tightened it up. It's not perfect because it doesn't appear lined up exactly right.

I have a stock thermostat.

So, at the moment I'm leaning toward changing out the cats tomorrow for known new good ones and probably leaving the cooling fan on during the next test which I will do in the cool of the morning when the testers open up (after a nice hot drive to get the car and cats up to temp).

Jon
 
Make sure your exhaust guys evaluate the cats for you. If possible cut one open and inspect it. Just so you can see if there was a problem and feel confident that it's resolved before you go back.

Thank goodness Minnesota got rid of their emissions test (less than 2% ever failed). I'll probably be pulling my cats off. One is already removed.
 
Thanks, Mike.

With the kind of cars that have come out in the last 10 years or so it seems so ridiculous to keep doing these dyno tests. They just started here in Virginia (DC metro) about 5 years ago. I think it will be hard to get rid of them because the neighbors (MD and DC) have them and the political climate here is such that they make a HUGE deal out of air pollution during the hot humid summer even though it is child's play compared to the real smog alerts that we used to have in LA in the 1960s and 1970s! The code red days around here are a joke.

I will have the exhaust guy check out the cats, for sure. The hard part is feeling confident enough to go try again. I get one free re-try by 8/16. Maybe the exhaust garage has a way to test before I go back.

Jon
 
Just Failed Smog AGAIN

Sorry for popping this up again but I have an update.

I tested on 8/2 on an extremely hot afternoon and failed NOx at 15mph by a tiny bit, passed NOx at 25mph by a small margin, and breezed through HC and CO with lots of room.

I decided to go conservative rather than spend a lot of money yet. So,
-- ran a can of CD-2 Emissions Pass through the gas
-- added a can of octane boost to the gas
-- added a bottle of Redline Water Wetter to the radiator to drop the head temps a little
-- ran a can of top engine cleaner through the intake system (with all the smoke afterward hopefilly cleaning carbon deposits)
-- did the test in the morning with outside temps in low 80s rather than near 100 last time
-- left the low speed cooling fan on the whole time

Result: FAILED both NOx (low and high speed) worse than before! Not even close on either one. The low speed NOx went up from about 850 to about 1150. The high speed NOx went up from about 720 to about 920. Got slightly better numbers on HC and CO.

Am I pointing to faulty cats for sure now???

Ruined my day and I don't feel well today either.

Jon
 
the cats will clean up your nox

mine didnt pass nox so i put new cat one only. I was broke then tested it and passed with flying colors had second cat the next week. and had it tested just to see how it did , with old cats my nos and co was high with new cats I passed 2001 smog standards. in so cal .I live in the area that has the most stringent smog standards in the counrty.
 
Thanks, Manny.

My CO is fine but the NOx is bad. I have been suspicious of the "no-name" cats I picked up last winter. I guess my next step is to replace them. I was trying to avoid that but didn't succeed.

Remember, I also went from 3 cats down to 2 but that should still work with good quality after-market cats I would think.

Jon
 
Hey Mike, I also live in Minnesota. And yes, it's a VERY good thing MN has no emissions tests anymore, as I'm sure half of the cars I've owned would never have passed. My old Taurus would never have passed, since when I bought it a head was cracked, had a bad head gasket, and lots of bad crap was coming out the exhaust before I replaced the engine, so I'm sure the exhaust was toast.
 
Well, it's back in the shop tonight.

My exhaust guy and I decided to rip the cats out and replace them with brand new Catco (Walker) three-way cats.

My problem could be that the previous cats I put in last February were two-way (no NOx reduction) rather than three-way as required for this car. I took off 3 stock cats (2 up front plus one in the Y pipe). If that's true, then I was getting no catalyst action on NOx at all leading to the very high numbers (1000 ppm and more). When it had the stock exhaust with 3 cats 2 years ago the NOx ppm was running 300 - 400.

I hope this does it. It can't be much else. The high NOx usually can only be 1) too advanced timing, 2) bad EGR, 3) bad cats. This 93 model has no EGR system so must rely on the cats. I can't believe there is anything wrong with the timing as it runs perfectly under all conditions.

The nightmare may soon be over and I can get my plates renewed!

Jon
 
Catco cats will fix it

This is a little late but I have a similar setup on my 1990, except I used Catco cats. I live in NOVA so same emissions test. My NOx increased from mid 300's to mid 700's after replacing stock exhaust, but that still passed. According to your posts, you were subjected to different limits than me. My 15 MPH limit was 1046 and my 25 MPH limit was 956. Have they changed the limits or are they different for different model years?
 
The Saga Continues

Zman,

My NOx was 300-400 2 years ago with stock exhaust. Now, with new exhaust (and THREE failed tests) it's still too high.

My guy just put on two new Catco three-way cats today and STILL failed the 15mph limit by quite a margin. Just passed the 25 mph limit.

WHAT IN THE HELL IS GOING ON HERE???

Please, someone give me a clue. I have a completely new exhaust system and two new cats - still high NOx. What's causing it? My exhaust guy is taking the TBird to a buddy of his to check engine stuff. I haven't touched the engine. My only mods are the new exhaust and a new MAC air intake.

My 93 TBird NOx limits for NOVA are around 850 and 750. These are lower than yours mainly because you are 3 years older. The computer system ups the limits each year as the cars age. It also depends on what they dial in for gross vehicle weight - the higher the weight the higher the limits allowed. I think they dialed in 5100 lbs for me. There is also variation from one tester to another and from one test system to another even though there shouldn't be. Sometimes they run low rpms (like 1300) in a higher gear and sometimes they run higher rpms (like 2000) in a lower gear causing different results.

EVEN SO, with new cats I should have passed well below the limits. You still run mid 700s with new cats?

We may have to try to get this car waived as "unfixable". You can do that in NOVA if you spend up to $460 and can't pass the test. I just sunk a few hundred into putting the cats on today!

I'm very frustrated. If I knew how to fix it I would. I just want this damn problem to go away. It's starting to take the fun out of tuning the TBird.

Jon
 
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