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running rich after header install

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Old Jun 16, 2006 | 04:31 PM
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Default running rich after header install

is this normal... i just ordered a new tune for the headers hope it will fix it.....
exhaust smells really rich... i have a leak due to a broken bolt not sure if it would cause rich a/f ratio.... also have a ORY so not sure if no cats would cause it to smell rich..... seems like im having bad gas millage but it could all be in my head let me know guys thanks
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Old Jun 16, 2006 | 04:59 PM
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No cats will definitely change the smell. If you truly have an exhaust leak, your O2 sensor will detect more air and think the engine is running lean, and will richen it way up until the O2 is reading at stoich. This may be what is happening.
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Old Jun 16, 2006 | 05:09 PM
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Originally Posted by LesPaul
also have a ORY so not sure if no cats would cause it to smell rich.....
if you had cats before then yes you would definatly smell a difference because there's no catalyst to "clean" the exhaust as it was before
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Old Jun 16, 2006 | 05:34 PM
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question...if you take out the cats and hook up the front 02 sensors at the headers and then put in one single big cat in the pipe after the y...the back 02's are tuned out....would this work?
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Old Jun 16, 2006 | 05:53 PM
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I dunno if the cat would get hot enough to do anything....why wouldn't you just go catless?
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Old Jun 16, 2006 | 06:29 PM
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was just thinking outloud....i thought the older setups had only on cat....
i am catless right now....
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Old Jun 16, 2006 | 06:58 PM
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Gotcha
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Old Jun 17, 2006 | 11:01 AM
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Thats right, like JT said theres no catalyst and the chemical elements from the gas aren't being caught.It's gonna smell richer till you get a tune. if you run 93* it won't smell as rich as 89*
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Old Jun 17, 2006 | 11:30 AM
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when u install lt's you need to get a tune regardless, i had a bad problem when i installed my pacesetters, my truck started getting multiple missfires, truck was shaking, when i put it in gear, it died. Wasnt pleasant at all, but i switched my wires, checked my plugs, and within 10 minutes it quit, and ran fine, no more codes. Then i got the nelson tune, and noticed a major difference in the way my truck performed. But as for running catless, u do notice a difference in the smell of ur exhaust, thats normal.
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