Bad Cats or O2 Sensors? Need Help...
01-18-2005, 03:18 AM
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Bad Cats or O2 Sensors? Need Help...
Car just registered a set of fault codes and is stumbling quite a bit. The faults are Fuel Trim: System to Rich Bank 1 and 2, and Warm Up Catalyst: Efficiency below Threshold Bank 1 and 2. I have the ASP downpipes (with the AWE RSKO4 kit) and have read in the archives of a few cats going bad. Any advice or experience would be greatly appreciated.
01-18-2005, 05:06 AM
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Running rich for whatever reason could foul the cats.
The bank 1 and 2 system too rich codes are usually attributed to a failed MAF, but if you've got the updated AWE K04 kit, you should have a Hitachi MAF, which is much less likely to fail.
-Dave Pramanik
-Dave Pramanik
01-18-2005, 05:34 AM
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Re: Running rich for whatever reason could foul the cats.
I do have the updated AWE kit with the Hitachi MAF and A-box converted to M-box. As far as the MAF goes, I just replaced it four days ago after the car shut down on me and would not run with the MAF plugged in. I still had the same fault codes when that happened as I do now after replacing the MAF. The car bucks and sputters with throttle and idles rough. This is why I think it might be the cats or 02 sensors.
01-18-2005, 05:40 AM
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The cats aren't going to affect your driveability unless they are seriously clogged...
which is unlikely. However, the primary O2 sensors could affect driveability and fuel trims. The coolant temp sensor is another common issue. Have you replaced it yet? Its a $5 part and is easy to swap out.
-Dave Pramanik
-Dave Pramanik
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01-18-2005, 05:50 AM
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Sounds like you should concentrate on the rich codes first.
The only cat failures I have seen as a result of running rich is a physically damaged catalyst substrate. This usually results in an exhaust restriction that won't allow your car breathe at high engine loads. If your runs ok under these conditions, then worry about the cats later.
As for the rich codes, fuel pressure and maf are the two big things to look for. Fyi, I have seen a lot of rich codes and driveablity complaints from air filter problems, such as one exposed to cooling fan air in the engine compartment. Somehow it can create turbulence across the maf sensor and give an incorrect measurement. Make sure there is an adequate shield between the path of cooling system air and your air filter.
As for the rich codes, fuel pressure and maf are the two big things to look for. Fyi, I have seen a lot of rich codes and driveablity complaints from air filter problems, such as one exposed to cooling fan air in the engine compartment. Somehow it can create turbulence across the maf sensor and give an incorrect measurement. Make sure there is an adequate shield between the path of cooling system air and your air filter.
01-18-2005, 06:08 AM
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Re: The cats aren't going to affect your driveability unless they are seriously clogged...
Codes were cleared and coolant temp sensor has been replaced (twice IIRC). Can't figure this one out.