2017 GM 6.2 injector replacement

[036.6turbo]

Anyone have any experience replacing injectors in a high milage 2017 6.2?

My sons 2017 GMC Yukon Denali XL appears to need #5 replaced, it ohms out fine when the engine is cold, but develops a miss when it warms up.

My buddy has a repair facility, long story as to why we took it to him, but he says the injector will stick in the head. Head will need to be removed injectors pounded out from the underside.

I guess GM added an umbrella seal in 2016 to the GDI motors to help keep them from sticking, but this truck has 200k on it soooooo....

Sounds extreme to me, but I have no experience with these.

 

[Chevy1925]

Sure its not spark or compression?

 

[036.6turbo]

Yeah, I guess as sure as one can be in these situations.

It doesn't mis fire all the time. Intermittently after running for a while.

Low compression I would expect it to always be low.

Same with a plug, good or bad, not once in a while.

As I understand it DOD or AFM on this iteration isn't a cylinder #5 issue. #1, #7, #6 and#4 are the AFM or DOD cylinders.

What the shop is saying is the injector shorts out internally once it gets up to operating temps for a while. Heat soaks. It ohms out fine when cold, runs fine when cold, but after driving for a while, the heat changes the tolerances in the injector body enough, that it will short itself out.

Shop owner does not want to attempt to replace them as (according to him) the odds they are stuck in the head are extremely high. Last one they did they had to remove the head and drive the injector out from the back side.

Seems extreme to me. But I have never done them.

But that is about to change, I told my son to fill the tank, add injector cleaner to loosen the carbon (long shot but whatever) then we will get back into it.

Just posted here to see if the shop owner is exaggerating things or if them being stuck is a real thing and does anyone know of any tips or tricks to get them out without destroying the fuel rail and pulling the head.

 

[Chevy1925]

He very well may not be wrong. If they do stick in the head, that head has to come off in order to get it out. He’s just trying to cover his ass cause he probably had to eat that last one.

Did they ohm it after the engine got hot to confirm that it’s out of spec?

If it is a circuit issue, then putting injector cleaner in her, isn’t gonna fix it lol.

If I get some time tonight, I’ll look into that procedure a little bit on how GM wants you to pull it out and if any techs have any easy ways of getting them out. Just before warned that Shop may not be game for trying those kinds of things.

 

[lutzjk]

On the newer transits at work. They are known for something similar and we forewarn customers before attempting it.

And James is right. Live and learn situation and you learn to cover your ass.

 

[036.6turbo]

He very well may not be wrong. If they do stick in the head, that head has to come off in order to get it out. He’s just trying to cover his ass cause he probably had to eat that last one.

Did they ohm it after the engine got hot to confirm that it’s out of spec?

If it is a circuit issue, then putting injector cleaner in her, isn’t gonna fix it lol.

If I get some time tonight, I’ll look into that procedure a little bit on how GM wants you to pull it out and if any techs have any easy ways of getting them out. Just before warned that Shop may not be game for trying those kinds of things.

It was not ohmed when hot. Upper intake has to be removed to access the injector itself, by then the motor has cooled. Other option would be to ohm the connector right at the ECM. Which is obviously possible but has not been done.

Comment about injector cleaner was not directed at helping restore the injectors functionality but rather help soften or remove carbon build up around the tip of the injector. Shop owner states that it is the carbon that causes then to stick in the head.

My research has shown that GM added an umbrella seal to the injector in 2016. That seal was possible added to keep debris from settling around the injector body in the bore of the head. (made me think of adding RTV to the high-pressure fuel lines where they exit the valve cove on the LB7s, to keep crap from building up) I mentioned that to the shop owner. These might not stick because it's a 2017 and should have that seal. His response was it wasn't external debris, but internal carbon that seized them n the head. That is what the cleaner was directed at, the carbon.

But as I look at the parts catalog, that additional seal doesn't show up until 2021, so it may be a mute point in this instance. Not sure where I got the 2016 from, YouTube has let me down, LOL.

Shop won't be doing the repair; my son and I will. Shop flat out said they would not even try. Shop owner is my neighbor, he built his house / pole barn the year after I built mine, we have a good relationship. He recommends trading the truck off. My son chooses not to do that, choosing instead to repair it.

 

[PureHybrid]

With those miles I'd be pulling the heads and changing lifters anyway

 

[036.6turbo]

With those miles I'd be pulling the heads and changing lifters anyway

Closed valley motor, heads come off, valley is still closed up.

But you are not wrong, my son and I are trying to decide how far to go. If the injectors come out without a lot of drama? Then swap injectors and move on with life. If they refuse to come out and we need to go deeper? Probably cam / lifters and whatever else is needed for full DOD delete.

Time will tell.

 

[Ron Nielson]

It was not ohmed when hot. Upper intake has to be removed to access the injector itself, by then the motor has cooled. Other option would be to ohm the connector right at the ECM. Which is obviously possible but has not been done.

P124C definitly a circuit problem. I'd make very sure it wasn't internal to the injector before doing a lot of work
Perhaps some help from this video

Source: https://youtu.be/lmoP01UMDYA

 

[036.6turbo]

P124C definitly a circuit problem. I'd make very sure it wasn't internal to the injector before doing a lot of work
Perhaps some help from this video

Source: https://youtu.be/lmoP01UMDYA

Thank you.

It appears from the video we're in the same position he was in. He replaced his injectors.

But his wiring looked WAY worse than ours. None of our injector pigtails show any signs of degradation like his.

 

[Chevy1925]

Closed valley motor, heads come off, valley is still closed up.

But you are not wrong, my son and I are trying to decide how far to go. If the injectors come out without a lot of drama? Then swap injectors and move on with life. If they refuse to come out and we need to go deeper? Probably cam / lifters and whatever else is needed for full DOD delete.

Time will tell.

No no, needs heads too, headers, tune, maybe an intake manifold and built trans

 

[036.6turbo]

No no, needs heads too, headers, tune, maybe an intake manifold and built trans

Don't forget the blower, he has a CTS-V in his past. Always talks about making this into a Denali V.

 

[NC-smokinlmm]

Do it…

 

[Cougar281]

Be very careful when you pop the fuel rail off. Make sure you don't pry one end up too much and bend an injector at the opposite end.

 

[NC-smokinlmm]

Have you tried any additives like Z Max or any other carbon treatment? I use the Z Max fuel and oil kit and I can tell a difference once I run it thru.

 

[036.6turbo]

Have you tried any additives like Z Max or any other carbon treatment? I use the Z Max fuel and oil kit and I can tell a difference once I run it thru.

Neighbor / shop owner recommended this to possibly loosen the carbon that could cause a problem removing the injector.

Again, it's not intended to restore the functionality of the injector, just help break the bond the carbon may have formed around the injector tip and the combustion chamber.

Truck has not acted up again, running smooth with no MILs on the dash, so he's going to drive a few tanks of fuel treated with additive, before we even try to R&R the injectors.

 

[NC-smokinlmm]

Try the Z max if that doesn’t do it, but the B&G is good stuff.