cat. converters
Thread Starter
Racer
Joined: Jul 2003
Posts: 446
Likes: 1
From: Washington PA
cat. converters
I have two codes that recently keep coming back 420 and 430. they are right and left catalytic convertor issues. It says: " convertor effieciency below threshhold. Does this mean I need to get new cats/or gut them. why would this all of a sudden come up?
Race Director
Joined: Dec 2002
Posts: 13,348
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From: SCMR Rat Pack'r Charter Member..Great Bend KS
Re: cat. converters (96redvette)
" convertor effieciency below threshhold. Does this mean I need to get new cats/or gut them. why would this all of a sudden come up?
All of a sudden? Your cats have been going "downhill" since the day the car was built. They just now dropped below what the computer thinks is the lower limit. The only thing that is sudden on our cars is a light bulb coming on. :) Everything else takes awhile....
Larry
code5coupe
:seeya
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: cat. converters (rocco16)
You might put a scan tool on it and see if there is any reason that could have caused the cats to fail. It's possible that they just went bad, it's also possible that something took them out. If something is causing damage to them it can get real expensive to keep replacing them.
My parent's blazer had a similar problem. It's a vortech engine with a known faulty fuel injection setup. Eventually it just starts leaking extra fuel. When in closed loop the computer can compensate for this by lowering the pulse width. However when in open loop it is dumping extra fuel that goes right through the engine and into the cats, eventually clogging them up. The dead giveaway in this case was the long term fuel trims. Over the long term the car has been leaning out the mixture to maintain the proper ratio because it was getting extra fuel somewhere.
They replaced the cat under warranty but they didn't fix what caused the problem even though we told them exactly what it was. That was about a year ago and I can feel the thing starting to act up again. In a few months when they have to replace their second $400 catalytic converter under warranty maybe they'll decide to actually fix the problem.
My parent's blazer had a similar problem. It's a vortech engine with a known faulty fuel injection setup. Eventually it just starts leaking extra fuel. When in closed loop the computer can compensate for this by lowering the pulse width. However when in open loop it is dumping extra fuel that goes right through the engine and into the cats, eventually clogging them up. The dead giveaway in this case was the long term fuel trims. Over the long term the car has been leaning out the mixture to maintain the proper ratio because it was getting extra fuel somewhere.
They replaced the cat under warranty but they didn't fix what caused the problem even though we told them exactly what it was. That was about a year ago and I can feel the thing starting to act up again. In a few months when they have to replace their second $400 catalytic converter under warranty maybe they'll decide to actually fix the problem.
