Failed emissions, got a new cat convert, and got WORSE!!!

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Failed emissions, got a new cat convert, and got WORSE!!!

November 17, 2006, 07:27:23 PM

After replacing a cat, shouldn't the emissions get better not worse?

The emissions people told me that I needed a new cat.

Here are my tests.
CO2 O2 HC CO NO (ppm)
13.7% 1.5 Max 213 MES 43 MAX 1.09 MES .01 MAX 2129 MES 4940

That was the test I did today at 15 mph and 1301 RPM

Old test

CO2 O2 HC CO NO (ppm)
11.8 4.0 87 .01 4279

That wasw at 15 mph and 1311 RPM

I didnt change a single thing engine wise. Why did it get so much worse? Is it finally my engine's time for a rebuild? On my old emissions papers I passed with flying colors.

Failed emissions, got a new cat convert, and got WORSE!!!

Reply #1 – November 18, 2006, 01:50:23 AM

So its way high in NOx? Is engine temperature running right? I had a clogged radiator that caused a failed NOx test. The pamphlet they gave me stated Hi NOx is often overheating related..

Other than that, I'd check the usual cr@p, the EGR valve, the solenoid that drives it. Your test is almost at idle compared to Maryland's "check it from 0-60 mph" test, so I guess I'd expect the EGR should pretty much just stay closed, unless it has some junk in it preventing it from closing all the way. Since you did Cat work, is the tube that leaks the exhaust back up to the engine for reburn still there?

Failed emissions, got a new cat convert, and got WORSE!!!

Reply #2 – November 19, 2006, 10:41:23 PM

Likewise I'd guess that it would be an EGR issue, assuming you're not just having a curb-idle test only.

Basically NOx is high when combustion chamber temps are too high.

Since I'm new to Ford's engines in particular myself, I wonder, do some of the computer-controlled, fuel-injected engines actually sometimes have the conputer open the EGR a bit at idle under certain conditions? I don't know for sure so take that with a healthy boulder of salt.

Failed emissions, got a new cat convert, and got WORSE!!!

Reply #3 – November 20, 2006, 07:57:07 AM

I dont think the problem is in the catalytic converter.

I suggest you try to see if you have any stored fault codes in your cars onboard computer.

Speaking from my own experience it could be a problem with the fuel vapor canister system. On a Camaro that I previously owned I had about the same problems with the emissions. It turned out it was the purge valve which under certain conditions sucks vapors from the canister and sends it into the intake manifold. The valve was stuck in the open position, therefore causing the engine to run "rich". The result was bad smelling exhaust and rough idle and at the emission inspection the CO was way out of range.

Checking the canistersystem was easy to do. I just disconnected and plugged the line from the canister to the intake, and instantly the engine ran much smoother and the emissions were down almost to zero.

Failed emissions, got a new cat convert, and got WORSE!!!

Reply #4 – November 20, 2006, 11:23:56 AM

Yeah, but he's got an NOx problem... if I'm reading his results right, it looks like CO was only 0.01%

Failed emissions, got a new cat convert, and got WORSE!!!

Reply #5 – November 20, 2006, 06:02:04 PM

What have you got your timing set at? Anything beyond 10 BTDC can raise NOx levels pretty high. Your EGR system could also be the culprit.

Failed emissions, got a new cat convert, and got WORSE!!!

Reply #6 – November 20, 2006, 06:10:55 PM

I'll jump on top of the dogpile and suggest poor/non-existant EGR function too.

Do you get any codes?

Failed emissions, got a new cat convert, and got WORSE!!!

Reply #7 – November 20, 2006, 08:12:45 PM

I will run the codes later this week.I am forced to drive on the already expired plate for a while, and I think I have to pay for the next test. I will check the egr to see if it is clogged, I also have a hole in my radiator. I planned on fixing that first, but I work alot of later days so I decided on the cat and emissions test first.

If that is what alot of you think, I will try the radiator. They also have to let my car idle for a minute first, because my steering colum is broken (Have to fix to pass saftey, a load of BS if you ask me), and they can't figure out how to start it so they make me walk out and start it before the next car is done. PITA.

I also have to brake down and time my car right, It is close, but not perfect. Thanks alot guys, Now I need to do a couple of things. I am just pissed that I spent so much on a friggin cat.