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Cat converters went out on my 7.4

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Old Aug 20, 2013 | 08:11 AM
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Default Cat converters went out on my 7.4

The good news is my truck is tagged Florida. Florida has no emissions, inspections etc...

Looking to eliminate the cats and go straight pipe. Choices are 02 simulators or tune the sensors out? My truck has a Hypertech chip and headers already. Thoughts and tips welcome. Thanks in advance.
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Old Aug 25, 2013 | 09:49 AM
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Sounds like a good excuse for a real tune to me
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Old Aug 31, 2013 | 06:39 AM
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tune it out. Any good tuner can do it easily.

Even if you cut out the rear o2's and don't do anything, you'll get a CEL but it wont hurt anything or affect performance.
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Old Aug 31, 2013 | 07:51 AM
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Originally Posted by RezinTexas
tune it out. Any good tuner can do it easily.

Even if you cut out the rear o2's and don't do anything, you'll get a CEL but it wont hurt anything or affect performance.
Other than you will never know if you have a CEL that will effect performance or economy.
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Old Sep 2, 2013 | 04:23 PM
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The 454's do not monitor the cats unless its a california 50 state emmission model. You can knock them out and it will never turn on a check engine for a failed cat DTC
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Old Sep 3, 2013 | 04:17 PM
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Is this the 95 (TBI) or the 2000 (Vortec MPFI)? The Vortec PCM will compensate for the change in exhaust flow. The TBI might have rough-idle problems and run a little lean. They are a little more sensitive to backpressure changes since they have no MAF. Didn't know about the CA-emissions difference, that is interesting. My experiences with two different 454's were both Vortec L29's and CA emissions.
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Old Sep 4, 2013 | 11:48 AM
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The 02's are there but do nothing. If you go to the emmissions readiness monitors on a non 50 state truck they do not monitor cats. Only EGR, O2 heaters and 1 other thing and I'll be danged if I can remember what it was.

Knock em out and you are good to go no tuning needed the pcm will handle the lack of cats just fine. I've had several of these BBC trucks I ported the cats on and left the tune as is with no driveability problems.
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Old Sep 15, 2013 | 06:48 AM
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Originally Posted by Quyonmob
Other than you will never know if you have a CEL that will effect performance or economy.
you can get a $50 OBD2 scanner and check every few weeks as part of routine maintenance. I do that anyway, even without a CEL, because sometimes trouble codes are still there.

Sounds like it won't be an issue on this truck though. Good to know.
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