Replacing NOX sensors

My mechanic is telling me that I have to replace the direct injectors as they must be removed to replace my NOX sensors. He says that the injectors have a teflon bushing that can not be properly reseated and if reinstalled they will end up leaking. So to replace all 6 will cost $2400 bucks! I can't find anything that says this is true, so I thought I'd ask this group. It's a 2016 with the 3.5L V6.

The cause of all this was rodent damage to the wiring harness for the NOX sensors. I'm not sure the sensors even need to be replaced, but my first inclination was to replace them while it was apart. Now I'm questioning this, as the extra $2400 for the injectors is painful, to say the least

Any input?

Handlebarmike2

 

You mean Knock Sensors not NOX sensors, yes they are in the valley of the engine.

Should be no need to replace the sensors as they very rarely fail but yea the harness is quite common to get chewed by rodents.

Not sure what it takes on a 3rd gen to change the harness, i know on 2nd gens it's not fun.

Your mechanic is correct that if the direct injectors are removed the teflon seals need to be replaced, the seals aren't terribly expensive but it takes some time to do it properly.

 

I think your mechanic is trying to rip you off typically injectors have two o-rings one at the fuel rail and one at the intake side that are serviceable.

I would get a second opinion.

 

I don't know about the price point as that depends on labor time and rates but direct injectors have Teflon seals that have to be replaced and the bores cleaned when the injectors are removed and it takes special tools to correctly install the new seals, they aren't like port injectors where it's just two O-Rings.

 

Ive done a ton of injector seals on Volkswagen/Audi and while they are a bit of a pain they aren't impossible to replace. Rebuild kits are everywhere for a reason. Different manufacturer but I can bet they are pretty much the same design on Toyota.

Replacing 6 whole injectors because you're too scared to replace the seals by themselves kinda screams inexperienced tech. Its not brain surgery

Kinda just sounds like a "go away" price

 

Ah I guess I misread that they want to replace the injectors instead of the seals, yea that's someone that's either uninformed or doesn't have the required tools.

The seal installer set is pretty inexpensive now the Lisle tools started making it.

 

You do VWs also? Sooooo, we got this Tiguan . . .

 

So there seems to be a general consensus that the teflon seals can be replaced. I've spoken to another mechanic and he also had reservations about doing so, saying that if you get one (out of the six) wrong in any way and not reseated properly you run a great risk of destroying a head. He also thought that replacing the injectors was the safest way to go, but he also said it would be expensive. The original guy just won't do the seal replacement, he says he doesn't want to be responsible for the potential risks if anything goes sideways. I may call a third guy, but I'm certainly torn between saving some serious money and going with a sure fire way to make sure it's 100% right. I hate these decisions!

 

Not sure how thats possible. You might have a combustion leak or simply not get the fuel rail fully seated .. but "destroying the head" seems a little extreme

 

I can understand if they aren't experienced with doing direct injectors they may be uneasy about it, admittedly I haven't done many but I don't see replacing injectors just to avoid doing the seals.
As a tech when I'm not familiar with/haven't done a job before I follow service info very closely, it's often very specific with stuff like this on what needs to be done.

The more critical part is getting the bores in the head properly cleaned, if those aren't clean it's not gona matter if you got new injectors with new seals it still could not seal.

I still question weather or not the injectors need to be removed to do just the harness but without seeing it I couldn't tell you.

 

My bad, I wouldn’t want to give inaccurate advice. TBH I have only installed port injectors so thanks for the info.

 

Direct injectors are f--kin expensive. I screwed up a job once on a Golf and got some metal shavings into the high pressure fuel rail. When I started the engine one injector got held open from the metal chunk and flooded that cylinder with fuel. The engine would barely crank over from the hydro-lock. I was freaking out thinking i had damaged the engine but it ended being ok thank god.. liquid fuel was literally dripping out the tailpipe

Luckily I didnt run the engine very long, it didnt even make it out of the bay.

I replced all 4 injectors and had to eat it, not fun. They were over $280 each. I still have nightmares about that one

 

I'm glad Honda's are ready to go out of the box..They only come in sets though.

 

Yea direct injection is a whole different animal, because of the high pressures involved there's alot of procedures that need to be followed and alot of stuff is one time use such as seals and the high pressure fuel lines. You don't want a 600-1000 psi fuel leak.

It sucks and adds alot of cost to many jobs that were once relatively simple and straightforward but unfortunately that's quickly became the norm for modern vehicles.

 

New ones typically are, the discussion was replacing only the seals vs replacing the injectors when they need to be removed to perform a service.

 

Oh gotcha...I've got all the tools for the seals,but I've never had to replace them unless the Head needs replacement.

 

What my guy said was the a leak could cause a little blowtorch that could do damage to the head. Too much to worry about,I'm getting the new injectors put in. Now we just have to find them.
You know, I love my Toyota, and I know so many other people that love theirs too. But this seems like a rather screwed up design flaw to me. First off, why does this engine need 12 fuel injectors? 6 direct inject and 6 "normal" injectors? What's the benefit? And second, why not make the rail so that you could just remove one side? And the "valley" seems like it has "Free rent for all mice for the first 6 months! written all over it. And yes, I live in a place with an abundant rodent population (SW New Mexico), but we raise the hoods on our vehicles every night and put a shop light in there to deter these little guys. Oh, and whose bright idea was soy based wire coatings that attract rodents. I mean, they just don;t seem to care how much you have to spend on maintenance. Sorry, I'm venting for my wallet...