2007 5.7 hemi quad cab bighorn 4x4with the MDS system
i put pacesetter long tube haeders no cats 3"off road Y pipe
into the paessetter. TFX exhaust system 1 3" pipe in 2 2 1/2 pipes out
sounds littel like (glass packs). but runs alittel rough is this the MDS??
did i f up my new truck.?? any input would be nice before i loose my mind.
I HOPE ITS ALL RIGHT?!!!

 

what did you do about the 02 sensors?

 

one set went into the headers then welded outher set 14" down into the Ypipe
it burns hot and yes my check engine light is on

 

That is most likely where your problem lies. Hopefully, if true, the Diablo tuner is coming out with a programmer that has the rear O2 eliminator available. If there are problems here, your truck is most likely going to run pretty bad. You might want to look into putting your cats back on, hope you saved them.

 

whats your check engine light code? im betting its for that second 02 sensor, you could always get a simulator to put in there

 

the 02's are getting to much flow and dont know what to make of it hence the code. get some helix coils and make an extender out of the bungs so they dont get the full force of the exhaust flow. try aslo resetting the pcm and see if it runs any better at first as the code shouldnt appear right away. oh and the rear 02s dont do jack for the af ratio. id check your gaskets and such as a leak up line at or before the collectors will casue some serious problems. if the leak is before the first 02 sensors your gona have bad ruuning and ****ty gas milage. imho you have a leak at the collectors or on the header to head gasket...

 

Double check for any leaks around the header gaskets. When I first put headers on my stang I couldnt get it tuned for crap because of the leak.

 

well?

 

could you please clarify what they are for then? the way i understood it, the rears told the computer if the fronts were working correctly or not. Well lets say the misture is too rich? wouldnt the rear sensor tell the computer that the mixture is too rich therefore making the AF ratio leaner?

 

i understand them to be for emissions. if you pull them out you'll throw a code sure but your truck will run fine other wise people would be having some serious issues in alot of cars. the fronts tell the pcm how rich what bank is etc.. thats simply how ive come to understand it though cuz on previous cars and most that come through my friends shop the first thing to go is the cat. so if it was really doin something for the af ratio i dont think they would be zip tieing them to the frame rail and puttin a sim in.