Trouble Codes Keep Popping up.
Thread Starter
Joined: Dec 2013
Posts: 14
From: IL
Trouble Codes Keep Popping up.
Hey All,
First off I own a 08 GT with BBK Headers, SuperMaxx Stainless Steel header exhaust system, and Saleen Series VI SC kit. I have been getting catalyst efficiency bank one and two codes popping on and off and an oxygen sensor every once in awhile being triggered. These codes are not constant and come on then disappear. Is it possible because of the upgrades done that these sensors are being triggered because of the added flow? I only have 11k miles on it and have had my sensors looked at and the catalytic converter and they are structurally sound and operate fine. I am trying to figure out what I need to do next and if I need to upgrade my cats or what.
First off I own a 08 GT with BBK Headers, SuperMaxx Stainless Steel header exhaust system, and Saleen Series VI SC kit. I have been getting catalyst efficiency bank one and two codes popping on and off and an oxygen sensor every once in awhile being triggered. These codes are not constant and come on then disappear. Is it possible because of the upgrades done that these sensors are being triggered because of the added flow? I only have 11k miles on it and have had my sensors looked at and the catalytic converter and they are structurally sound and operate fine. I am trying to figure out what I need to do next and if I need to upgrade my cats or what.
4th Gear Member
Joined: Jul 2011
Posts: 1,329
From: Michigan
the cats may look OK, but are you sure the guts are still there? If you're getting "catalyst efficiency" codes, it means they aren't working.
longer version: modern cars have two sets of oxygen sensors. The "upstream" sensors are in the exhaust header before the cat(s) and are used by the PCM to monitor the engine management. The voltage from these sensors will normally oscillate very rapidly between slightly rich and slightly lean. The "downstream" sensors are in the H/X pipe after the cat(s) and are used to monitor the catalyst function. The voltage from these sensors won't vary as much and they should oscillate much more slowly. If the PCM signal thinks the signal from the upstream and downstream sensors look too much alike, it'll throw catalyst efficiency codes.
it's possible, if you have the stock cats, that the ceramic substrate could have cracked and is allowing exhaust gas to bypass the catalyst. I haven't seen a case where that's intermittent, though. My Ranger has been blaring the Check Engine light in my face for a month now because of this, and it's been on constantly.
longer version: modern cars have two sets of oxygen sensors. The "upstream" sensors are in the exhaust header before the cat(s) and are used by the PCM to monitor the engine management. The voltage from these sensors will normally oscillate very rapidly between slightly rich and slightly lean. The "downstream" sensors are in the H/X pipe after the cat(s) and are used to monitor the catalyst function. The voltage from these sensors won't vary as much and they should oscillate much more slowly. If the PCM signal thinks the signal from the upstream and downstream sensors look too much alike, it'll throw catalyst efficiency codes.
it's possible, if you have the stock cats, that the ceramic substrate could have cracked and is allowing exhaust gas to bypass the catalyst. I haven't seen a case where that's intermittent, though. My Ranger has been blaring the Check Engine light in my face for a month now because of this, and it's been on constantly.
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