A frustrating P0153

On my new to me 2003 Tundra 4.7, problems started with a P0420. Not knowing their age I replaced all 4 02 sensors(denso). The previous owner replaced the complete exhaust system, including installing headers. None of it looks new, so I am not sure when the issues started. I removed the cats and rewelded the joins that were definitely leaking. So that, and the new sensors seemed to cure the P0420.

That's when P0153 started. So after thinking about this for awhile, and looking closer at the exhaust headers. The 02 sensor installed on the right side has a elbow adapter. It is not directly in the exhaust stream.
I am hoping I can cut that elbow partly off, run a tap through it, then install the O2 sensor. I am definitely trying to avoid removing the header if at all possible.

What do you guys think, will it cure the p0153? I really hope so.

Also, I haven't check the manifold or intake for leaks yet.

 

You should never put any kind of spacer on the upstream oxygen sensors with OEM exhaust. I would imagine, but do not know for certain if that's the case with aftermarket. Snap some more pictures of the 90* elbow if you can, or just see if it looks removable.

 

That elbow is definitely welded in, I thinking they did it that way because of space limitations. Maybe worried that the sensor would hit the transmission, or not be easily replaceable.

 

Any reputable exhaust shops around to get their thoughts, or see what they would charge to cut-n-weld in a new proper m18x1.5(??) bung on each header?

 

I got a coworker who is a ticketed welder, he is telling me there isn't enough room if I keep the header bolted up.
The left side is fine, they never welded an elbow. I think I am going to pull the cat on the right side to verify if there is threads. Then cut that 90 off square as possible, run a tap and install.

I guess I was just wondering if my theory would fix the issue

 

I think you’re barking up the right tree.

 

Right.

Also right.

They put that elbow in as a weird way to make the O2 sensor replaceable. Some headers have the passenger side O2 bung in a spot where you don't have enough clearance to back a sensor out. Mine look super close, I'm not sure if I can back it out ot not.



I think you'll get frustrated trying to work on it with the header attached. It's a bit of a pain to remove and replace, but if your studs aren't rusty I would remove it. You may want to have a bung welded in at a different angle to avoid clearance issues, and cut that elbow nonsense out/weld the hole shut.

 

What a bizzare place to put it. Is there no room on the underside of the header? From what I see, it looks ike there's plenty of room.

If its harness related, they should make a harness extension instead.

 

Right, the driver's side is installed on the underside. Never thought the harness not being long enough was their issue. Seems like more work to install it this way than to extend the harness.

 

It isn't about the harness. It's the lack of space when you want to replace your O2 sensor. A few guys with JBA shorties weren't able to back bad sensors out.

It would have been smarter to put the bung up high if anything.

 

Yeah, I am worried about the lack of space. I just ordered a new bung, so I can get this all sorted out. I am going to try and struggle with cutting that elbow first, mainly because I am stubborn.

 

I don't blame you. If anything at least the passenger side is the easy side to pull.