HELP with Emissions AGAIN!

jonroe

Registered User
Folks,

I spent a fair amount of time discussing my emissions inspection failures here two years ago. Here we go again. This is the Northern Virginia metro area.

Here are the numbers:

HC 87 limit, 06 reading, 84 limit, 09 reading ....... GOOD!
CO .48 limit, .04 reading, .47 limit, .03 reading ...... GOOD!
NOx 655 limit, 1101 reading, 594 limit, 1005 reading ...... BAD!

The first numbers are for 15mph (1319 rpm), 2nd gear I think
The second numbers are for 25mph (1316 rpm), 3rd gear I think

I had done nothing special prior to the test. Oil is clean and car runs perfect. There is nothing wrong that I know of. The weather was cool (60 degrees) and I left the cooling fan running all during the test (to try to limit combustion temps).

I suspect the problem is with my after market exhaust system where my two new (2 years ago) 3-way Catco cats are sitting about a foot or more further back in the downtubes than stock. I suspect they just don't stay hot enough to do the job. I really struggled to pass last time when the cats were brand new. I'm scheduled now for a VA DEQ certified diagnostic session. I doubt they will find anything wrong. Then, I'm angling for an exemption. This car does NOT have an EGR system so that presents a problem right away for the cats to struggle by.

Can anyone suggest a better course of action. This is getting to be a royal PIA!! :( :confused: :mad: :eek:

Thanks.

Jon
 
High NOx reading indicates that your combustion chambers are too hot. You might be able to "fix" this problem by pulling the octane plug and running some very high octane unleaded race fuel. Another person I know well *cough* was in the same situation and he had to detune timing by 9 degrees across the whole map (using EEC tuner) in order to pass.

The cooling fan is good to leave running full time when on a dyno (since most of those smog places don't have a fan) but it won't help your combustion temps.
 
yep, i think ur problem are the cats, they are too far back, unless u wanna grab a torch and hold it underneath the cats to heat them up, but i doubt they will let u do this, well anyways, u are going to have to move the cats closer to the manifolds, its either that or pay them wink wink under the table, and have them pass you,
 
Try this old trick

retard the timming 3 degree,s wrap your headers to make sure all heat gets to cats and then(believethis clamp a few unnecassary vacuum lines and put some moth balls into your air box,,Very odd it sounds but ive seen it work)
good luck, Vetteman



89 SC 5spd
76 vette
84 vette
87 vette
70 GT torino
 
Just went through this 2 months ago. I'd just rebuilt the engine, drove it for a week and took it down for the rolling tests required in Houston and failed high speed Nox with the same exhaust I've passed with for 3 years in flying colors. I run tru-dual through SCP down tubes and SCP high flow cats (I forget what manufacturer actually made them back then) located about a foot back further than stock also. When I installed this system, there were very little increases in CO/HC/NOx levels so I'm not so sure your cats are the problem. I found a vacuum leak (pcv hose came off where it connects under the stock throttle body inlet tube) allowing un-metered air into the engine and raising combustion temps. Also, ran the codes and found a short in the Cam sensor harness causing the engine to run in a constant cold start cycle (I assume) and replaced that with a spare. Passed this time with plenty of room to spare.
Sideline to this story is, I did all my own work and diagnostics (the Texas form allows you to either go to a liscensed shop or diy) and wrote down my time/cost at current shop labor rates, plus the diagnostic fees Ford would have charged to run the codes along with the price of the harness (it was a brand new spare I've had several years, and which by the way, is obsoleted by Ford according to the local parts guys) thinking I would be that much closer to getting a waiver it still failed. That ended up getting causing a few words with the emmissions tech after he made some snide sarcastic remarks about me billing myself out for the repairs and how that wouldn't apply towards a waiver. It's getting to be a heck of a country when you need your own business card to validate your own repairs to satisfy the state emmissions gestapo. Even better when your car company obsoletes the parts you may require to pass the test in the first place! Stock up on spare parts guys, we're going to need them. This episode almost made me go buy a 69 Dodge Charger. I almost can't wait until the SC's are 25 years old so I don't have to take their tests anymore. But by then they'll probably have herded us into hybrid/electric cars on automated roads where you don't have to steer and are forced to go 55 mph. God save us. A very sad ending to last stage of the dinosaur fossil fuel era.
 
Steve,

Your doing it the hard way. Just tell the DMV your car is out of the state and won't be back for at least another 6 months. Sounds too easy doesn't it.

Call the local place that issues plate renewals and play the what if game and see for yourself. You will probably be asked to sign a document saying the car is out of state and promise to get it inspected within 10 days of returning to the state. They may even audit you and call to see if you have gotten the inspections at some later date. Nope...the car is still out of state.

David
 
i would turn the fan off for more heat, mostly warmwer is better even put cardboard in front of radiator if need be and pull the octane plug and put 92 in it maybe spray the maf and throttle body with cleaner
 
EGR ANYONE?

i still blame the cats, they are sitting too far back, in fact ask any smog tech and they will tell ur cats need to be as close as possible to the exhaust manifolds in order to operate correctly,

my cats are no less then 6 inches from the manifolds, thats with the horrible downtubes removed.

u might wanna try to lower the fuel pressure. also

there is this article on TCCOA that shows u how to pass emissions
 
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David Neibert said:
Steve,

Your doing it the hard way. Just tell the DMV your car is out of the state and won't be back for at least another 6 months. Sounds too easy doesn't it.

Call the local place that issues plate renewals and play the what if game and see for yourself. You will probably be asked to sign a document saying the car is out of state and promise to get it inspected within 10 days of returning to the state. They may even audit you and call to see if you have gotten the inspections at some later date. Nope...the car is still out of state.

David

Now thats great stuff! I'll file that one away for next years battle. So how many "out of state" cars do you have? :)
I used to keep my cars registered to my parents address as they don't live in a "non-attainment" county, so no tailpipe tests. Got to be a hassle dealing with the insurance companies though as they want to nail you for the higher rates in the Houstron Metro area.
 
I had a conversation with my mechanic who does all the "hard" work on the car that I don't do. He put on the whole exhaust system. He doesn't toally buy the "cats are too far back" argument yet. He wants to do some more detailed diagnostics. I'm droppinig it off with him tomorrow evening. I hope he can give me some ideas. He is a very good guy.

Darkstar, where is this TCCOA article?

Also, I'm not familiar with "pulling the octane plug". Can you explain more?

Thanks for all the thoughts so far. I'll keep you updated this week.

Jon
 
My mechanic is running all kinds of diagnostics on the car today. So far, he found that the MAP sensor on the firewall was not working correctly. I should know in the morning whether fixing that has helped or not.

Jon
 
Conclusion -- PASS

We finished with my car today. The car passed with a large improvement in the NOX numbers that does not seem to be related to the cats or their position. My mechanic didn't think the cats were the problem. New numbers today:

NOx 655 limit, 310 reading, 594 limit, 277 reading ...... GOOD!

The numbers improved from 1101 and 1005 - substantial.

The RPMs used were higher at this test facility, around 2100 instead of 1300. It seems that results would be better with the higher RPMs.

My mechanic did a complete diagnostic work up and:

-- found codes KOER 225, KAM 185 and 189
-- repaired wire connector at the knock sensor....(hmmmmm)
-- cleaned the MAF sensor wire....(sounds reasonable, I should have done it)
-- checked O2 sensors and found right one slower switching than left one but did not replace it
-- performed complete BG Products Induction Service Kit

So, it sounds like a collection of emissions service issues.

Well, at least I have another two years until the next time.

Thanks for your interest and comments. :) :) :)

Jon
 
As a sidelight to this story, I was very fortunate while my car was in the shop. On Wednesday afternoon a hail storm blew through the area near the repair shop (about 30 miles from my work) and I didn't know it. When I called later about the car my mechanic said that my car escaped hail damage because it happened to be on the dyno (for emissions) in the garage at the time of the hail. Several other cars parked outside suffered moderate damage from the hail that was 1" to 2". WHEW!!!!!!!!!!!!!!!!!!!!

Jon
 
Wow, that was quite an improvement in test results. I just squeaked by the emissions test earlier this year, so I will probably need to fix/change something next time since I already tried the octane plug and other tricks. I live in Vienna and was wondering who your mechanic is in case I need help with one of those "hard" problems. So far I've done all my own work (except the custom exhaust) but I'm always on the lookout for a good mechanic in this area since they seem scarce.

Randy
 
You got it, Zman.

I was surprised as well with the large reduction in NOx. I guess those few "tune-up" fixes made a big difference. By the way, since you're in Northern VA, what's up with the allowed values DROPPING every year as the car gets older? I thought they would RAISE the allowed limits a little each year to allow for a car getting older.

The guy that does ALL my mechanical work is:

Jim Wacker
Chantilly Steering, Suspension & Alignment
14059 Willard Road
Chantilly, VA 22021
(703) 968-3502

I recommend Jim with no hesitation. He is a true old style customer service guy who is very experienced in lots of areas. He had some assistance on this job from a sharp guy (who is great on emissions) from the shop next door to him.

He did my entire exhaust, motor mounts, brakes, spark plugs, and helped with emissions in 2002 and 2004. He's also done work on my other car (wheel bearings, brakes, alignment). I'm setting up to have him rebuild my differential with new 3.27 gears and all new parts next month. He's getting a new mechanic who specializes in setting up differentials and transmissions.

He's busy for a good reason.

Jon
 
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