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-   -   cats (https://www.performancetrucks.net/forums/gm-engine-exhaust-performance-21/cats-486695/)

04-4x4 Aug 6, 2011 06:32 PM

cats
 
The cats just blew apart on my truck, and I was wondering about just running a straight pipe instead of replacing them.. anything need to be down to stop the computer from throwing a code?
(and I just looked for a solid half hour on here to no avail)

budhayes3 Aug 6, 2011 07:31 PM

Yep, you need to have the PCM tuned to turn off the catalyst inefficiency and over temp codes. If you have tuning software like EFILive or HPTuners you can do it yourself, if not, one of our sponsors such as BlackBear or Wheatley can do it for you (links to the right>>>>
Might as well get a complete custom tune while your at it :cheers:

04-4x4 Aug 7, 2011 01:05 AM

I figured so
and thanks for the reply it's greatly appreciated :cheers:

AKlowriderZ71 Aug 7, 2011 01:08 AM

It will run just fine without the tune, but the CEL will be on until you get it tuned. It will not change how it runs and drives.

Suburbazine Aug 7, 2011 02:43 AM


Originally Posted by 04-4x4 (Post 4748642)
The cats just blew apart on my truck, and I was wondering about just running a straight pipe instead of replacing them.. anything need to be down to stop the computer from throwing a code?
(and I just looked for a solid half hour on here to no avail)

You don't even need to replace the pipe. They are pretty easy to gut once broken. Just get a plasma cutter and cut a 1.5" hole in the front edge, hammer out the insides, and weld back up. As long as you do it neatly, it looks like you've still got cats on the truck for emissions inspection.

04-4x4 Aug 10, 2011 11:04 AM

Another question (sorry if it is on here already)
but I gutted the cats (thanks for the idea suburbazine) and after about 10-15 minutes of driving down the highway, it puts the motor into derate mode, can't go faster than 30 mph. Is something else wrong with her or?
Thanks

hvactech08 Aug 11, 2011 12:56 AM

also it hard to run with out some sort of a muffler? or will just help out

letsrun97z Aug 11, 2011 03:16 AM

My passenger side cat just went out notice 6-9mpg loss until I got it replaced. No check engine lights came on

KLUG'S SS Aug 11, 2011 06:46 AM


Originally Posted by 04-4x4 (Post 4750731)
Another question (sorry if it is on here already)
but I gutted the cats (thanks for the idea suburbazine) and after about 10-15 minutes of driving down the highway, it puts the motor into derate mode, can't go faster than 30 mph. Is something else wrong with her or?
Thanks


Hmm strange? Did you get like the reduced engine power message or something?

04-4x4 Aug 11, 2011 06:53 AM


Originally Posted by KLUG'S SS (Post 4751226)
Hmm strange? Did you get like the reduced engine power message or something?

once the CEL comes on it won't rev past 1500 rpm and it losses all kindas of power. If the CEL doesn't come on, it's fine. it seems, right around the time the cats should be warmed up to running temp it does that.


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