What are my options to fix this mess?

Gentlemen,

This is something I never would have thought I'd see. The exhaust down pipe tubing has been welded to the exhaust manifolds. Holy crap. I suppose that's what I get for buying a car sight unseen and having it shipped. Both sides are the same.


What are my options? Can I replace the manifolds myself?

Thanks,

 

At least the cat is still fully intact and the downstream O2 is OK. I guess the previous owner wanted true dual exhaust?

What can you do?

Well, there's a Y-pipe that bolts the upper arms of the "Y" to the back of each cat, one leg per cat. You could hit up a yard for that and the resonators, and toss on a muffler to get back to stock, which would involve popping out and replacing that broken stud, and getting new nuts and gasket for the flange if there is one (I forget). You'll need to cut the existing exhaust pipe off and grind the weld out with an angle grinder.

Or you can hit any reputable exhaust shop and they can probably cut the pipe, weld a new flange onto the pipe, grind out the weld flat, replace the stud and bolt it back together.

EDIT: Wait. Shit. I just noticed the steering intermediate shaft in the pic. Like, it's welded straight to the f'n manifolds eh? What the fuck?!

Yikes. I mean, at least the upstream O2 is intact? Maybe you could weld a bung farther down the pipe to attach a fouler, and throw your O2 on the fouler and eventually get it right so you don't throw codes?

Otherwise, you need new cats, and either go with a cat back exhaust kit, or have a shop attach the existing dual pipe setup to the cat.

 

You can but it’s a tedious job.

 

If you remove the studs I don't think it would be too bad to cut the pipe off and grind off the weld. Looks like you need to replace one of the studs anyways.

 

i'd just leave it exactly how it is

 

Shit, I just noticed the steering shaft. I glossed over that being welded to the manifold. WTF. Prior post edited.

 

Noooooooooooooooooo, it's bad, but not THAT bad.

In my previous posts I stated she was throwing a P0174, and was told the upstream O2 sensor could be the culprit, so I got underneath to take a look. It was the first time since I had her that the timing and weather worked out so I could crawl around and take a look.

That sensor is a Denso, and it says "Toyota" on it. Is that original equipment? The other three sensors appear to be no-name generic.

I suppose the big question is, Can I clear the codes without buying a new exhaust system? She idles smooth. Torque showed between 703-711 rpm in neutral. It has good power. Only 163,000 miles. The air filter is new and not some K&N-like thingy. I cleaned the MAF sensor a few days ago.

 

P0174 is a lean code. I don't know that this is the source of the lean code. Clear it if you want. But know if the upstream sensor is aftermarket, and the plugs are showing no signs of fouling, that sensor may be the problem. Its purpose is to read combustion gases exiting the manifold into the cat, and checking for composition (lean/rich/etc.)

 

Given you have another ongoing thread where you mentioned having P0174 code, have you checked any of the suggestions mentioned in those threads ?

Dreaded TRAC OFF and VSC TRAC and Check Engine Lights | Toyota Tundra Forum

 

Yes. That's why I was underneath looking at the upstream Bank 2 O2 sensor.

 

shifty, as I stated in the post right before yours, that upstream sensor is a Denso, and it says "Toyota" on it. Is that the original, 18-year-old sensor?

 

Yes, potentially. But you should have two upstream sensors on a V8. You said one was OEM and one was not, I thought. If I’m looking at the driver side in your last photo we are talking about (bank 1), and you’re telling me that one is denso, but all the others are not, that means the passenger side (bank 2) is not Denso, and you’re throwing a P0174 code which is “bank 2 lean”. I’m just pointing out, the truck uses the upstream sensor to evaluate if the exhaust gasses are lean or rich, so if that passenger bank 2 sensor is not denso, and the ECU thinks that bank is lean, knowing the history of aftermarket sensor problems…

or maybe I misread your words above?

 

The Bank 2 Upstream sensor is the Denso.

 

Gotcha. I thought you were referring to the pic above, which is bank 1.

 

Does swapping out that possibly old sensor seem like a good place to proceed. I did the starting fluid dance looking for vacuum leaks, and cleaned the MAF.

 

This is easy for me to say since it's not my money but if I was in your shoes and I was keeping this Sequoia, I would consider putting the exhaust back to original.

This picture you posted in the Sequoia forum of your existing cats, tells me you could do your Sequoia a favor by restoring back to original for many reasons, least of which is your present codes.

 

Whilst I agree wholeheartedly, it would be advantageous to get it running right the way it is, to give me time to make a plan and collect the necessary parts.