Ok, so assuming I am going to take out 4 and put in two... Where do they relocate the 02 sensors to?

 

I'd just find an honest shop to do the work. Period. Fortunately, not everyone is out to take advantage of there customers. It's bad business for one, but some couldn't live with that dishonesty flaw as its a VERY unattractive sort of character.

Then there's the Karma thing lol.

 

I'm a bit confused as well. I had a previous post on the same topic but was unaware of how this works. My 94136s are on the way as we speak. I know I have 4 cats but now I'm removing all 4 for 2? Like Enielsen said, where do the other o2 sensors go? I live in Fl is my truck going to be illegal now without all 4 cats? And is it really going to be that hard to find a shop? Sorry to thread jack but I think this will answer all questions.

 

Brew, an honest shop would not have done that work in MA because what they did was illegal.

 

Guys.

Magnaflow #94136 cats have O2 bungs already. So your O2s are a direct install. Otherwise, models like the 94136's twin, ( 94106 ) will require the O2s to be mounted after the cats. Shops will charge more for that work.


Is this for your Expedition? Or you 2007 F150? Just in case you did not know, your F150 already has only 2 factory converters. Trucks assembled January 2005+ all have 2. Early production 2005s ( Dec 2004- ) & older years to 1997 have 4.

 

Correct George, and they offered to just delete my rears but I wanted the fill replacement

 

Darren thanks for the clarification. Yes its the 07 150, that explains everything lol.

 

There you go man, direct replacement and no worries about the sensors.

 

So for those of us that have 4 cats, how do we (by we, I mean the shop) setup the 02 sensors if going from 4 cats to 2 so that they don't throw codes? Maybe a diagram would be helpful if anyone has one.

 

Simple. The new cats, granted you order the #94136s with the pre-mounted O2 bungs, will need mounted with the bungs toward the rear of the truck, away from the engine. They will fit right in place. '97 - '03 have the rear sensors after the rear cats, and Cali emissions trucks have them in the centers of the rear cats. 2004/2005s with 4 cats have them right before the rear cats ( does not make sense to be either ). All in all, it will all fall right into place. Just be sure they drop the downpipes and fully weld so you do not have any health harmful exhaust leaks.

 

By drop down pipes what do you mean?

 

Also how many 02s do I have and where are they at ? I know u said they are before the rears, but are those the only 2?

 

The exhaust pipes that are connected to the manifolds. Catalytic converters are usually fully welded in place on those as a one piece unit. The unit is connected to the manifolds, and Y pipe joint.

Six and eight cylinder vehicles have four. The front two are right after the manifolds and read the air/fuel ratio. Those are very critical. The last set monitors catalytic converter efficiency. Which basically, your cat starts clogging and goes bad, a CEL will illuminate with the PO420 code. If you remove your cats, or have a leak in that area, the PO420 code will also illuminate from the rear sensors.

 

So have them leave the upstream 02s there, weld in a down pipe, replace the downstream cats with my new magnaflows and insert the downstream 02s into the bungs of the magnaflow cats?

 

You got it! Replace the front cats with a pipe.

This assumes that you can find a shop that will do it. It depends on where you are.