Hi-flow cat SNAFU.

Well, after getting my alternator sorted, I decided to move on to the check engine light issues on my 97 5.2 355, it shows codes for both upstream sensors heater and inactivity.

Today while I have the car on the lift to do the alternator, I noticed that my upstream 02 sensors were hitting the frame... I originally thought that the hi-flow cats were clocked wrong or the o2 bungs were just welded in the wrong spot -

Well I think I have figured it out - the cats are installed on the wrong sides - left one on the right and vice-versa.

I temporarily put some thick rube tape on the frame so the wires did not touch and short.

When my new o2 sensors arrive I will swap the cats from side to side and see...

 

The car came like that, the pipes look very similar with the exception of the o2 bungs. If I am wrong, I will still have to pull the cats and weld new bungs on in a better spot.

 

I have ordered NTK sensors from FerrParts.

 

It looks like there is a ton of room for the sensors on the inboard side - they are currently in about the 2 o'clock pos. on the right and 10 o'clock on the left, thus they hit the frame when the engine torques - if the cats were swapped left to right there would be no interference.

The pre and post cat sensors seem right since the post cat sensors read correctly on the scanner but pre cat sensors are basically dead (.01-.03v) and hence the codes.

I will swap them around when my new O2's get here.

 

Well to update on this, I knew they were aftermarket cats, but only when I pulled them did I see the label - these are Fabspeed cats, they DO NOT FIT - the o2 bungs are wrong -

I had to put them in the press and press the o2 bungs so the sensors would not hit the frame - the last sensors were crushed by the frame.

 

I bet they changed them - just a note, I have always read that O2 sensors are supposed to be mounted at a no more than 15deg. upright position to avoid collection of water/condensation that can short out or corrode them.

Your description of left @ 8 o'clock and right at 4 o'clock would put them facing downward no?

I suspect maybe fabspeed changed the bung location due to the problems I have? I now have no more issues after pressing them but still this sucks, I have to replace 2 sensors and now the replacement sensors look like they are wrong (NTK sensors)

 

Don't get me wrong I really appreciate the help!