06-07 LBZ Performance Discussion of Chevy and GMC Trucks with LBZ Duramax Turbo Diesel Engines Related To Performance And Longevity

Well got the cat-back, and about to order the downpipe... but

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Old Jun 22, 2009 | 09:29 PM
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Default Well got the cat-back, and about to order the downpipe... but

i have a question for you guys like always haha. its sayin that the free flowin exhaust may throw codes 401 & 404. but i climbed under the truck and saw no o2s or any other sort of wiring in the exhaust, am i missin somethin?
 
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Old Jun 22, 2009 | 11:08 PM
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i think you will be alright
 
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Old Jun 22, 2009 | 11:18 PM
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some lbz trucks will throw a code when you straight pipe it, but a finger stick should take care of it.
 
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Old Jun 23, 2009 | 02:27 AM
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Originally Posted by 2500HeavyDuty
some lbz trucks will throw a code when you straight pipe it, but a finger stick should take care of it.
Yeah listen to this guy, he knows what he is talking about....
 
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Old Jun 23, 2009 | 08:33 AM
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My truck did not throw the p0401 untill I blocked the EGR.. but yes, its easily fixed with a finger stick..

Also, EFI LIve and PPE programmers will both block the code.
 
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Old Jun 23, 2009 | 09:29 AM
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Originally Posted by HeavyChevyDMAX
its sayin that the free flowin exhaust may throw codes 401 & 404. but i climbed under the truck and saw no o2s or any other sort of wiring in the exhaust, am i missin somethin?
Nope, no O2's, it's simple backpressure. When the EGR opens X airflow flows to the intake, this changes the mass airflow readings. When you open up the exhaust (cat delete, less restrictive muffler) then the EGR opens, X airflow just changed and is not corrisponding with what the ECM should be reading. The result is a code for EGR and/or MAF incorrect readings. Now, depending on what programming you have and emissions requirements your truck came with will deternime if a Check Engine Light will actually come on or not. Some throw a soft code where you know nothing about it and the truck acts normal. Some throw a hard code and the CEL comes on, truck changes peramiters and throws itself into a 'limp' mode of sorts to protect itself and the environment.
 
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Old Jun 23, 2009 | 08:14 PM
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My truck did not throw the p0401 untill I blocked the EGR.. but yes, its easily fixed with a finger stick..

Also, EFI LIve and PPE programmers will both block the code.
yea i got the PPE excelorator, i figured i could use it to delete it, but would the code come on everytime i turn the truck on? or will it only come up once, and once i delete it will i see the code again?

thanks, JIM
 
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Old Jun 23, 2009 | 09:19 PM
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As long as you are running a tune from the PPE, it will not come up once you clear it.
 
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Old Jun 24, 2009 | 08:14 PM
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cooool thanks fellas. cant wait to put everything on this weekend!

New York with all your damn emissions! makin it a pain in my *** to go downpipe haha
 
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