Damaged catalytic converter after fuel injector service!

[email protected] · January 7, 2020

I want to start this post because I could not find others that had this issue. My truck is the 2016 GMC Sierra Dinali 1/2 ton 6.2l v8, 8 speed trans. I have 34000 miles and decided to listen to my dealership and go ahead and do the GM recommended 30k mile service (even though the manual recommends this at 45k). This service included a throttle body and fuel injector service. While the truck was in the shop, i received two emails from GM indicating problems with the emissions system and one other. Anyway, I talked to my service adviser and they said that is normal during this service. Drove the truck away and I did notice a nice improvement in overall performance and response. So I was happy at first.

My first indication of a problem was the next morning when I attempted to do the remote start from my GMC app. It failed to start. I then tried to use my key fob and it also failed. Turns out my truck had some codes and check engine light was on. Called the dealer and scheduled a quick stop in to have the codes cleared. Maybe they forgot to clear them during the service? The code was cleared and my remote start worked again. However, the next day the same thing happened. No remote start. Went out and my check engine light was on again. Went back to the shop and they confirmed the same code was set again. I don't remember the code right now but is related to emissions system. Anyway, the service rep says I have a bad catalytic converter. He also said that is why they don't want to do fuel injector service on the the 2016 year trucks any more because this is not the first time they have had to replace a cat for this issue. They are not going to charge me for fixing this ($1000) but I have to wait now until it comes in to get it fixed. Evidently during the process of spraying the injector cleaner in the engine, it is damaging the cat so bad that it stops working.

Has anyone else had this issue? It seems like if this is going to be an issue every time I do this service, then for one, I might not find a dealer to do it, and two, I won't want to do it myself. This is a service that should be done every 35k or so. They claim it is only a problem on the 2016. Others agree? It seems like a possible solution would be to drop the cat before doing this service. But if you drop the cat at the down-pipe, would this cause any additional issues other than being loud?

Lsgun1 · January 8, 2020

Wouldn't make sense that it was isolated to 2016 only. Yes you can drop the cats and it will be super loud but no ill affect on the truck if you just want to do the service then put that cats back on.

Snowcamo · January 8, 2020

This may help understand why. Its like a filter in a sense. Ours may be made of different internals, but the principal is the same.

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TJay74 · January 8, 2020

It is because the cleaner they use is causing the cats to get hot and overheat which then melts the catalytic converter substrate material and ruins the cat. Then the rear O2 sensors notice the loss in the catalytic converter performance and then trips the code. Luckily the cats are covered for 8yrs/80k per the Federal requirement.

Z45 · January 8, 2020

Quote

GM recommended 30k mile service (even though the manual recommends this at 45k).

Not GM recommended but dealer recommended to enhance their profits. I don't see anything in the owners manual that says to do throttle body or fuel injector service. Thats a BS scam to bilk you for needless services. Run away fast anytime the dealer recommends some service costing you money, its BS.

Captive customer. Dealer sets the hook with free oil changes and then when you come in for them, they look for the opportunity to upsell you on other often unnecessary services such as; Fuel induction service, transmission fluid flush, replace Cabin filter, replace Air filter etc. Often these services are not currently recommended by the owner’s manual. It’s designed to make money for the dealer and since they are giving free oil changes, often the customer feels obligated to purchase the recommended accelerated dealer services. In other words, you are money in the bank. If even half of the customer fall for this, they rake in a huge profit from a free oil change.

Edited January 8, 2020 by elcamino

Ozer · January 8, 2020

While on this subject of delaer services, for anyone reading.. DO NOT get your trans flushed. Do a pan drop with a filter change.

Transmissions go Boom after about 20l-40k miles. Happened to me, happened to others.

garagerog · January 8, 2020

No need for fuel injector "service" on anything under 100.000 miles as long as you're using top-tier gas and throw a 20 oz. bottle of Techron in the tank every blue moon or when you can get a BOGO on it. I doubt anyone using Techron on a semi-regular basis would ever need "fuel injector service" for the life of their gasser. Diesels may be different. As elcamino mentioned, it's strictly a dealer up sell and profit item.

mitchely03 · January 11, 2020

On 1/8/2020 at 11:51 AM, Ozer said:

While on this subject of delaer services, for anyone reading.. DO NOT get your trans flushed. Do a pan drop with a filter change.

Transmissions go Boom after about 20l-40k miles. Happened to me, happened to others.

Pretty bold to make that claim. I got my trans fluid replaced but no filter change at 60k miles. The dealership didn't want to drop my aftermarket y pipe since i didn't have new gaskets. I haven't had any problems and I drive the shit out of my 15 5.3.

Edited January 11, 2020 by mitchely03

Snowcamo · January 11, 2020

Pretty bold to make that claim. I got my trans fluid replaced but no filter change at 60k miles. The dealership didn't want to drop my aftermarket y pipe since i didn't have new gaskets. I haven't had any problems and I drive the shit out of my 15 5.3.

What he said is bold and should be taken as words of advice. The flush never really ends well. Something to note he isn't the only one who experienced this failure. Many have and just haven't put the pieces of the puzzle together. On a fresh to moderate mile trans as yours you'd likely not have much of an issue because there's not much wear to cause debris flow through the the trans. Also its been said the new fluid deteriorates the friction clutches. There's allot to it and it really is more to it, but moreso it leads to failure in short order. It took me twice to learn this to be true. Both times the rebuild cost me. First both were due to stuck valves that burnt clutches.

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KARNUT · January 11, 2020

I never do or did dealer injection cleaning ever. Use top tier fuel as mentioned in most manuals, you’ll be fine. I have a few old vehicles never a problem. One usually gets one tank of fuel a year, two the most. Acura Intagra Type R. It’s turning 19 years old. I drive it once a month that’s it. Runs like a champ.

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Nitrousbird · January 12, 2020

On 1/8/2020 at 2:51 PM, Ozer said:

While on this subject of delaer services, for anyone reading.. DO NOT get your trans flushed. Do a pan drop with a filter change.

Transmissions go Boom after about 20l-40k miles. Happened to me, happened to others.

Pan dropping alone is the incorrect way as well. The best way is to drop the pan, change filter, refill. Then remove the tranny fluid outside port on the radiator and run a hose to a jug. Start the truck, run it until you just start seeing air bubbles then shut off. Refill tranny and do it again. Do this until all fluid is new.

A pan drop only changes a portion of the fluid. This method changes all the fluid without the hazard of flushing.

Snowcamo · January 12, 2020

Pan dropping alone is the incorrect way as well. The best way is to drop the pan, change filter, refill. Then remove the tranny fluid outside port on the radiator and run a hose to a jug. Start the truck, run it until you just start seeing air bubbles then shut off. Refill tranny and do it again. Do this until all fluid is new.

A pan drop only changes a portion of the fluid. This method changes all the fluid without the hazard of flushing.

I have to disagree. Here's why for the sake of good convo...

Mainly because your running the trans dry in turn stressing (causing wear due to lack of lube) the pump and leaving debris throughout which is not good.

Now if you connect the return hose going back to the trans to a jug of sorts filled with trans fluid as to not allow the pump to run dry(bubbles) then I can see a positive benefit.

The trans pump is a vane style which should not be ran low as damage to the pump vanes and cavity the reside in. As an example the pump is just like a boat outboard/ inboard water impeller, once you run it dry damage occurs due to lack of lube.

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LDM · January 12, 2020

1 hour ago, Nitrousbird said:

Pan dropping alone is the incorrect way as well. The best way is to drop the pan, change filter, refill. Then remove the tranny fluid outside port on the radiator and run a hose to a jug. Start the truck, run it until you just start seeing air bubbles then shut off. Refill tranny and do it again. Do this until all fluid is new.

A pan drop only changes a portion of the fluid. This method changes all the fluid without the hazard of flushing.

This the the best method for changing transmission fluid. I've used this method for over 20 years on dozens of vehicles and have never had an issue with a failing transmission. But I also don't let my transmissions go 100K+ miles like so many people seem to do before changing the fluid. Also don't like this new "lifetime fluid" nonsense so many car manufacturers are trying to get away with either. But then again they don't care if you don't change the "lifetime fluid" and then the transmission dies after 100K, its out of warranty and time for you to buy a new vehicle anyway.

Snowcamo · January 12, 2020

4 mins in he repairs and upgrades the pump with a new boost valve in the pump in the first video. The second is a test of the rings that seal the 4,5,6 and reverse clutch packs. 6mins in it shows what's still left in the pump. It would be flushed out the second go around or immediately if the return had a source of fluid. If one is going through the work to disconnect a hose might as well disconnect another.

Edited January 12, 2020 by Snowcamo
Video edit

tbarn · January 12, 2020

I think there may be a misunderstanding of what a trans flush is. All the machines I've seen just drain old fluid out a cooler line while refilling into the cooler side. Nothing the trans doesn't see every mile. Just new fluid. Not saying I'm a proponent of this method, just don't see how it could damage anythig. No more fluid "flushing" than normal.

Edited January 12, 2020 by tbarn