Hey guys I have a quick question for ya.
I have a 2001 F150 with the 4.6 Triton.I recently had the cats cut out, replaced with pipe and added a Flowmaster single inlet dual outlet muffler.Shortly after the check engine light came on which I knew would happen because of the o2 sensors but it smokes now.The truck didn't smoke until after the exhaust mods...It still runs fine and doesn't use any oil..Is it possible that not having the cats threw the computer off enough to make it run rich??OHHH the o2 sensors where put back in the system and plugged back up..Thanks for your time and I would appreciate any and all feedback.

 

its probably just all the unburnt fuel from the engine. the cats are what burns the unburnt fuel. put 2 high flows on there.

 

Well running no cats yeah your gonna have smoke. x2 on the hi flow converters.

 

Your o2's ever been replaced? ive ran no cats for a while and never had smoke probs then one night i layed into it and saw a huge cloud behide me turned out my driver side Front o2 was bad and making it run rich. replaced the o2's no more smoke

 

You will run rich if you delete the cats and don't adjust the tune or get mil eliminators for it. The ECU will throw extra fuel at the cats to try and warm them up to operating temp but sense they aren't there you will just be wasting fuel out the tailpipes.

 

You need to make the two downstream sensors into dummys. I will have to give you the address when I get home on how to do it.

 

Heres one way to make the back o2 sensors dummys, it works I have done it on 3 trucks.
http://cobrasvt.homestead.com/files/milelims/index.htm
click on the pic and it will give you a parts list, go to radio shack get the parts and put it togather like the pics show and that should fix your check engine light also unhook the battery cables to reset the check engine light but you may still have some smoke because like the others have said thats what the cats do they burn the stuff before it goes out.

 

http://paladinmicro.com/PalMFrame00.htm?wks=mil
This one is a little easier, I think.