5 years of recurrent emission issues, with no end in sight. Solution?

Hi:
I am the original owner of a 2006 tundra -- limited, 4 WD. 193,000 miles now. About 5 years ago a progression of emission system issues began. It started with both cats going out around the same time. Since then I've spend about $12,000 on it. Three different mechanic shops. They have replaced various pumps, valves, sensors, even the pipe where you fill the gas tank. Each cat has been replaced twice.

A month ago, the check engine light came back on. The engine went into "limp mode," lost power, and could barely go up an incline. This was new – it never went into limp mode before.
The code that came up involved the secondary air pump. I just dropped $3,600 at two different shops, to replace the secondary air pump (the first shop failed to fix it, so I took it elsewhere). I got it back finally, and the damn check engine light came back on.

I feel like I am piling up my money and setting it on fire.
It seems nothing is working -- they address the codes that pop up, but the same code or a new one pops up later.

It seems the root problem is beyond recognition. Does anyone have a clue of what the root cause of all of this is, assuming it is not just a long list of unrelated, coincidental failures? If the root cause cannot be properly diagnosed, would it be more cost effective to replace the entire engine, or the entire emission system? Does an engine replacement come with a new ECM and emission system? Cost?

Here's the list:


05/08/2015

H&O says code P0430 catalyst below threshold bank 2
code P0455 -evap system large leak "find defective purge control valve

10/29/15

replace purge valve; fuel induction cleaning; timing belt

11/3/15

Toyota of Seattle: evap system failed test, gas cap leaking; replaced; then found catalytic bank 2 failed

11/20/15

H&O replaced both cats and O2 sensors $1,988

8/17/2017

code 0441 incorrect purge flow; found leak at gas cap; replace purge tank and gas cap

10/4/17

replaced fuel tank filler pipe (plus other non exhaust maintenance)

4/13/2018

replace both catalytic converters and thermo sensor. Note: "it is unusual for catalytic converters to fail unless there is a secondary fault. common faults: fuel delivery, ignition system and mechanical failure.

8/23/18

Toy of Seattle. "both catalytic converters are wrong for his vehicle. O2 sensors found plugged into the cats" [I later learned that the O2 sensor does plug into the cat, so T of S tech is just plain wrong.

6/28/2019

code 0420 catalytic system below threshold. P0441 evap system incorrect purge flow. Bank 1 does not match bank 2. Bank 1 O2 sensor has major fluctuation on steady cruise. more test, suspect failed cat bank 1, and recommended replacing purge solenoid.
repairs: replaced bank 1 catalytic converter, replaced upstream air fuel ratio sensor; replaced vacuum switching valve

5/7/2020

code P0420 bank 1 cat below threshold; smoke test, no leaks; data from O2 sensors says not switching, rear O2 sensors had high voltage readings (stuck rich), technician says to replace both rear O2 sensors. Replaced BOTH rear O2 sensors and cleared code

5/21/20

Toyota of Seattle. Code P0430 bank 2 cat below threshold; its failing and should be replaced.

5/28/20

Greg's Japanese Auto, Seattle. Replaced bank 2 cat and O2 sensor (passenger side). They suspect the recurrent fouling of the cats is due to engine burning oil

9/30/2020

Greg's Japanese Auto in Seattle. Cats are ok; replaced the .....
Did Hockett mess up the "purge flow" repairs in 2015 & 2017?


I haven’t updated the chart since 9/30/20, but as I said above, the secondary air pump code came up and I have had it replaced twice in the last month, but two different mechanics, and the check engine light came back on within 24 hours of the last fix.

I'd love to hear if anyone has a clue as to what is happening, and what I can do to get this fixed. Thanks

 

Following along in hopes you get some answers.

 

Hey at least your saving the planet, while you choke on all the emissions from China!

 

Look up Hewitt tech. They make an air injection by pass kit for about $450 last time I looked.

You'll have that installed, and never have another problem out of the air injection system ever with no limp mode.

My understanding of what happens is water will get in one of the pumps, and it will stick open or closed. The system won't work, so your truck goes into limp mode. The by pass kit tricks the trucks computer into thinking they aren't stuck, and are working properly.

There are also some block off plates, and a few other things too that I don't have personal experience with.

@FrenchToasty @empty_lord

 

Are you in a state that requires emissions testing?
If not just bypass everything and roll on.

 

With all these issues, how does your truck run? Sounds like your cats are going bad prematurely due to incorrect air fuel ratios. Hope you're using Denso/Toyota O2 sensors.

 

I wonder if you don't have an electrical or grounding issue somewhere. How does the harness going to your ecm look, are your main grounds clean and secure?

 

Yes, you are piling up your money and burning it. I’m not sure I’ve spent $12,000 repairing any/all of my vehicles ever combined. There is a root issue likely causing all of these failures and it has yet to be diagnosed. Truck is running rich? Or burning oil? Both should be obvious, As the smell, or the smoke would be easy to observe. Maybe the computer is getting bad info? Maybe the injectors are leaking? Maybe the MAF is not working properly? Your story is why I don’t trust mechanics at large. They don’t know the root cause and don't have time to find it. Just throw parts and money at it. Not sure where you can find a trusted mechanic to properly diagnose your vehicle, but I wish you the best of luck. I would have sold that truck long ago before I spent $12k on it.

 

Ouch. As others have said, the bypass kit will probably work for you. If your truck is running fine (besides the limp mode) then install the bypass kit and move on. If your last pump failed because it blew itself up (common) you could have the same issue I did, in that the valves are stuck because there are plastic bits jammed in there that won't allow them to operate. In that case, the bypass kit didn't resolve my issue. Get the Hewitt Kit and give the dude a call. He knows this system better than all the mechanics you seem to visit. The kit solves 90% of these codes. If your valves are stuck, they need to be removed and cleaned, or replaced, which is one of the 10% chances.

Also, if your codes are coming back within 24 hours of getting it "fixed", they are hosing you and replacing the wrong parts. Codes don't tell you exactly what's wrong. They give you a place to start looking. STOP paying them until they fix it right. If they refuse, credit card chargebacks are great for this reason.

I haven't worked in a garage in 20+ years, but are most mechanics just shit nowadays? Can't fix anything, just replace what a computer tells them. That's not a mechanic, that's a Genius Bar employee.

 

This smells like a bad ground. Too many fluctuating answers from selected sensors.

 

@Tundra2 @5N0W808 We appreciate you guys spreading the word about the SAIS Bypass Kit. @natapoc I am sorry to hear you have been put through the ringer. We are happy to help trouble shoot anything with the Secondary Air Injection System and walk through the Bypass Options. I have included a few threads below with more information about the failure prone system.

What Does the Secondary Air Injection System Do?
https://www.tundras.com/threads/what-does-the-secondary-air-injection-system-do.113683/

What Do My Secondary Air Injection Error Codes Mean?
https://www.tundras.com/threads/what-do-my-secondary-air-injection-error-codes-mean.113686/

How to Fix Secondary Air Injection System?
https://www.tundras.com/threads/how-do-you-fix-the-secondary-air-injection-system.113688/