Failing emissions
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Failing emissions
My dad has a 93 lumina that failed the carbon test for emissions. The tester said the cat was getting red hot so its probly clog or on its last leg. Anyhoo he took it to a mechanic and they said that carbon buildup could be the problem and that that can take off the manifold and scrape it off. First off i thinks thats a load of crap, and i tol them not to do it. My main question is if a clogged cat could cause a car to fail the carbon part of an emissions test?
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From: Alvin, Texas.
http://www.txdps.state.tx.us/vi/Misc/rerf/asm_faq.htm
This might help. I failed for NOX and HC's.....but it helped out when I only needed a cat.
I am thinking the car is running rich, really, for a cat to be GLOWING. Carbon coming from unburned fuel...but that's my thought.
This might help. I failed for NOX and HC's.....but it helped out when I only needed a cat.
I am thinking the car is running rich, really, for a cat to be GLOWING. Carbon coming from unburned fuel...but that's my thought.
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From: Eastern WA
What do you mean by carbon test? Are you referring to hydrocarbons (CO) and he flunked the HC emissions part of the test? If so, this is a consequence of a rich mixture. An overy rich mixture will result in a converter running much hotter than it's designed for. Continued driving with a overly rich mixture ultimately results in converter failure. Because of this, the problem causing the rich mixture must be fixed before replacing the converter. Several things can cause the rich mixture; is the CEL on? On a properly operating and tuned FI engine, the converter really doesn't do much under normal driving. Floor it or drive with a cold engine are a few exceptions to this.
BTW, that glowing red converter is potentially a fire hazard.
BTW, that glowing red converter is potentially a fire hazard.
Last edited by CowboyBilly9Mile; Aug 27, 2005 at 01:48 AM.
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Cowboy, Everything you said is correct except hydrocarbons are HC not CO. CO is carbon monoxide and that is a different spec in the test. All the emissions tests I've seen had readouts for CO and HC. I think there was a third but can't remember.
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Thankyou for the replies. He bought the car used a couple weeks agon and I had to reconnect a map sensor that was not connected becuase it had a cel light. So I am thinking the people who owned it drove it around with out ever fixing the problem, there for ruining the cat. Thanks for the help.
