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Discussion Starter #1
My catalytic converter is shot, but I purchased a new high performance one just last year, can they go bad that quickly? I know I am running rich though, my exhaust is always black and dripping soot, will that impact my smog test even with a new cat?
What could be the cause, a cooler sensor?
 

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Sounds like an O2 sensor or one of those cold-start enrichment thingies you modern-car people have. Running rich *will* damage the cat in the long run, but the only way to know is to test it (see if you can get a pre-test from your mechanic).

Good luck!
 

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Actually, running rich will damage a catalytic converter rather quickly. I've seen them red hot when the engine is running too rich. Then they plug up and get very restictive.

The ECU should adjust the mixture. A proper mixture should not look sooty black out the exhaust. But the ECU can do that only if it gets proper inputs. If the coolant temp sensor is faulty, the ECU won't know the engine has warmed up and will maintain the rich mixture needed during cold starts. If the O2 sensor is faulty the ECU stays in 'closed loop' which is also a slightly rich mixture by default.
 

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Another "run rich" culprit can be the MAP sensor. If this sensor leaks, its signal to the ECU will be incorrect resulting in incorrect spark advance. This will affect primarily low speed operation (high manifold vacuum). Easy check, remove the vacuum hose that goes to the MAP sensor it starts on the intake manifold and goes into the sidewall behind the pass seat. Suck on it, if you can draw air, you have a leak (sensor belows is fritzed).
 

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No MAP sensor in the Motronic, Elio. As was stated, most likely culprits are the O2 sensor or the coolant temp sensor. Any codes in the computer?

Keith, do you have a digital voltmeter? The CTS specs are in the CarDisc, and you can find a procedure for testing the O2 sensor on Greg Gordon's page (www.hiperformancestore.com - the tune up procedures are for L-Jetronic but a lot of the stuff is the same). If not I can help you when I get back next weekend.
 

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Discussion Starter #10
No MAP sensor in the Motronic, Elio. As was stated, most likely culprits are the O2 sensor or the coolant temp sensor. Any codes in the computer?

Keith, do you have a digital voltmeter? The CTS specs are in the CarDisc, and you can find a procedure for testing the O2 sensor on Greg Gordon's page (www.hiperformancestore.com - the tune up procedures are for L-Jetronic but a lot of the stuff is the same). If not I can help you when I get back next weekend.
Missed this....no volt meter Tom, mat take it to Eddie, call me when you get back, thanks.
And thanks again all.
 
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