Having exceeded 500miles since installing the downstream O2 sensor and no CEL, I now conclude that the broken sensor was responsible for both the P0141 and P0420 that I had.

Lesson
The P0141 first showed up before the P0420 in my case. Therefore I would advice that while you work through the check list to eliminate the cause of your P0420, if you have a P0141, work on that first before going for an expensive CAT change or CAT delete.

My O2 sensor won't budge,tried pipe range still no joy

erico2k2:
My O2 sensor won't budge,tried pipe range still no joy

You may need those that work,on exhausts to assist. It may need to be heated with a blow torch. Have you tried running the car for a minute or 2 before attempting?

My mileage has also improved, though I haven't done a real test but, I now get around 200miles by the time the needle reaches halfway. This was about 170miles before. Will do a proper test

Piyke:


You may need those that work,on exhausts to assist. It may need to be heated with a blow torch. Have you tried running the car for a minute or 2 before attempting?

Yes bro I ran it from PH to sapele then went to crank it no joy the location of both culprit is delicate to a blow torch'

adanny01:


Yes i guess eventually i must. Instead of that i will fit a test pipe with an O2 space fabricated on it as i have read. The hollow section of empty CAT may not be a good thing for the engine and a straight pipe is recommended instead. For now, i want to try the spacer and if it fails, then the straight pipe thingy.

For now, most mechanics i have asked have no idea that a spacer of that dimension exist. Thats because most spark plugs threads are same but the nut are either 19 or 21mm while the O2 sensor has a bigger threading with 22mm. With the new $ exchange rates, the spacer is too expensive to make an orders. I think i can fabricate the spacer by welding a 22mm nut to a fitting pipe and having the other pipe threaded to correspond to the CAT O2 hole. It shouldn't cost more than 1k for labour and parts.

oga, did you later do this? I'm in same dilemma at the moment

Specialist900:
oga, did you later do this? I'm in same dilemma at the moment

Never got to do it until my CAT got blocked. During removal my O2 sensor was damaged.

adanny01:


Never got to do it until my CAT got blocked. During removal my O2 sensor was damaged.

I have the code on my baby boy, I also have a friend who has same code on his 09 accord, he said that since the code popped up his fuel consumption has increased. I need to get the defouler to remove the CEL