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150,000 miles. Main issues are EPA exhaust Junk. Replaced a few sensors but get dash light for not regen often enough. only issue now is getting timing belt and water pump replaced due to parts shortage. Can't find places outside of dealer to work on engine. Otherwise, truck runs great and still does all I bought it for.
Your probably at the end of life for the DPF. Or getting close. I only have 40,000 miles and keep driving cleaning exhaust came up once and I spend more time on the highway than city. So I have no idea what that was about. I run the torque app and didn’t see anything other than it was time for a typical regen.
Then the other day it came up x miles till max speed. But that went away. The torque app was showing crazy values for the second nox sensor. At this time the second nox sensor stays at zero most of the time.
To many poor quality sensors on diesels now days..
 

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Your probably at the end of life for the DPF. Or getting close. I only have 40,000 miles and keep driving cleaning exhaust came up once and I spend more time on the highway than city. So I have no idea what that was about. I run the torque app and didn’t see anything other than it was time for a typical regen.
Then the other day it came up x miles till max speed. But that went away. The torque app was showing crazy values for the second nox sensor. At this time the second nox sensor stays at zero most of the time.
To many poor quality sensors on diesels now days..
To be honest, my next step might be to bypass. Hate to go that route, but tired of $1400 for sensors and still have same issues. Love the truck and the diesel. Once I get timing belt replaced and I’m doing front hubs and entire rotors and brakes. Should be ready for another 150k
 

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The injector change was for model year 2020-up, possibly late 2019-up. Definitely not for prior years or any earlier than that.
 

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Also, to clarify the above, the injectors don't come from a different supplier. The injectors are still Denso, they just have a higher pressure rating while GM left the actual rail pressure the same in an attempt to prevent injector failure. There were some rumors/false assumptions that GM switched to Bosch injectors, but that's not what happened. Bosch injectors wouldn't work with the Denso system anyway and there's no way Bosch or Denso would approve the use of mixed components like that.
 
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Also, to clarify the above, the injectors don't come from a different supplier. The injectors are still Denso, they just have a higher pressure rating while GM left the actual rail pressure the same in an attempt to prevent injector failure. There were some rumors/false assumptions that GM switched to Bosch injectors, but that's not what happened. Bosch injectors wouldn't work with the Denso system anyway and there's no way Bosch or Denso would approve the use of mixed components like that.
Makes sense. Seems probable that expensive EPA recertification would not be required either for such a minor change. I wonder of the new injectors are a compatible drop in option for the older systems.

GM has had some injector issues with the big Duramaxes also, have come across a few YouTube videos documenting that.
 

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Makes sense. Seems probable that expensive EPA recertification would not be required either. I wonder of the new injectors are a compatible drop in option for the older systems.
Unfortunately they're not, the cylinder head also changed to work with the new injectors. :( So different injector and head part numbers compared to previous years.
 
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Interesting. GM would not spend the money on changing the head for no reason at all! Thanks for the info. Gonna keep feeding this puppy lots of lovely cleaning/lube additive.
 
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Interesting discussion over on the COFans board with a fuel systems engineer involved. This post was particularly illuminating in response to a vendor who sells purportedly higher quality injectors:

For starters, the number of holes, the spray angle, the hydraulic flow......these are all design parameters that are part of the overall combustion design, which includes the shape of the piston bowl and an overall goal for EGR strategy and engine out NOx. It's something that is reached through a very simulation heavy design approach, looking at droplet formation, penetration, plume interaction, mapping local temperatures etc. I can't imagine how this is going to be improved in an aftermarket, low volume injector.

They talk about the 'hardened alloy Bosch" this-n-that, but there's no such thing as premium material injectors instead of 'run-of-the mill' stock injectors. Fuel injectors are subject to the most difficult wear and durability effects of any engine part. They are always made with materials that are selected for performance above all else. Nobody is like "Let's make the tip 1008 plain carbon steel and save fifteen cents." Not even GM.

So if you assume pretty much every injector is a high quality, precision mechanism, then it turns out the actual key to injector reliability and durability is going to be exactly how the OEM uses it. This is in the calibration, and it circles back to that combustion system design we started with. In meeting program goals for NVH, emissions, fuel consumption, performance, how close did the OEM have to come to the design limits of the injector design?


And similarly, how good a job did the OEM and the injector manufacturer do in testing to ensure the operation is within design limits. OEMs test vehicles at 50 kHz data collection to see what is really going on in the FIS over a broad collection of operation. OEMs run engines on durability cycles and tear down the injectors to look at all of the critical surfaces in detail. It's a lot of tedious and expensive work, and you have to complete it all with the final production calibration.

In short, the key to improving injector life is probably not in a different injector. It's in changing the system targets and operating the injectors at a more relaxed strategy (lower injection pressure, less or no use of multiple injection events)......basically doing the things the OEM can't because they have to hit emissions and noise targets.

I remember when Ford figured out their (Navistar) 6.0l diesel was seeing cavitation at idle due to multiple injections. So they issued a recall and just turned off the multiple shots on every truck that came in to a dealership (even if just for an oil change). The trucks all got a lot louder and people were super pissed, but given cavitation that was probably the only solution. You aren't going to 'hardened alloy' your way out of cavitation damage in throats or holes.
I recall GDE saying that the GM settings have the pilot injections on all the time. GDE turned the pilots off when they were deemed to not be necessary. I believe this includes at idle. My truck does seem to be a little more "diesely" at idle with GDE's settings, that immediately goes away once revs rise. I actually like the extra bit of clatter at idle. Pulled all the sound deadening foam off the top of the engine to maximize the diesel vibe, cuz I am a child at heart. Have also gotten a few confused looks from big diesel truck owners and even had a few fuel pump chats with them as the big diesel owners were unaware that the twins had a diesel option :LOL:

Anyway, some good discussion in that thread. Talking out my ass here, but stock trucks with failed injectors makes me wonder if GM leaving the pilot injections on all the time is too much for the original Denso injectors. Perhaps the "injector failures" are really just due to lazy OEM calibrations which leave the pilot injections on all the time, which could work the injectors harder than necessary.

It also makes me wonder, if that is indeed the case, why GM would not simply change the settings instead of going through the trouble of updating the injectors and head in the '18 and later engines while they were at it. GM did issue a recall card in the mail to change the settings regarding the emission sensors. Who knows if GM changed anything else, maybe they did change the injection strategy also. All I know is my truck still ran like a farm tractor on GM's updated settings vs. GDE's.

Here is a link to the thread, the above quoted bit as near the end:

 
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Interesting discussion over on the COFans board with a fuel systems engineer involved. This post was particularly illuminating in response to a vendor who sells purportedly higher quality injectors:



I recall GDE saying that the GM settings have the pilot injections on all the time. GDE turned the pilots off when they were deemed to not be necessary. I believe this includes at idle. My truck does seem to be a little more "diesely" at idle with GDE's settings, that immediately goes away once revs rise. I actually like the extra bit of clatter at idle. Pulled all the sound deadening foam off the top of the engine to maximize the diesel vibe, cuz I am a child at heart. Have also gotten a few confused looks from big diesel truck owners and even had a few fuel pump chats with them as the big diesel owners were unaware that the twins had a diesel option :LOL:

Anyway, some good discussion in that thread. Talking out my ass here, but stock trucks with failed injectors makes me wonder if GM leaving the pilot injections on all the time is too much for the original Denso injectors. Perhaps the "injector failures" are really just due to lazy OEM calibrations which leave the pilot injections on all the time, which could work the injectors harder than necessary.

It also makes me wonder, if that is indeed the case, why GM would not simply change the settings instead of going through the trouble of updating the injectors and head in the '18 and later engines while they were at it. GM did issue a recall card in the mail to change the settings regarding the emission sensors. Who knows if GM changed anything else, maybe they did change the injection strategy also. All I know is my truck still ran like a farm tractor on GM's updated settings vs. GDE's.

Here is a link to the thread, the above quoted bit as near the end:

I had a guy at work say there is something wrong with my truck. Does it have any oil in it?
I said it’s a diesel…… oh he says… lol
But
If GM leaving the Pilot injection on all the time was hard on the injectors why is the consensus suggesting that there is more tuned failures than stock.. ?
Reading as much as I can on these failures l think the problem with the tunes is turning up the rail pressure to get more power is damaging the injectors. Just a thought.
From the first drive of my Colorado 2.8 I was in love with it. Amazing mpg and no screaming engine going up hills.
Mine was getting extremely noisy. It was so loud it was hard to use hands free phone.
I decided to fill it up with Shell high cetane diesel and add half a bottle of Amsoil all in one diesel additive…. Wow what a difference it’s very quiet now. I have to turn the radio off to hear the diesel clatter now.
Really love this truck and would be disappointed if an injector failure destroyed the engine….
 

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I had a guy at work say there is something wrong with my truck. Does it have any oil in it?
I said it’s a diesel…… oh he says… lol
But
If GM leaving the Pilot injection on all the time was hard on the injectors why is the consensus suggesting that there is more tuned failures than stock.. ?
Reading as much as I can on these failures l think the problem with the tunes is turning up the rail pressure to get more power is damaging the injectors. Just a thought.
From the first drive of my Colorado 2.8 I was in love with it. Amazing mpg and no screaming engine going up hills.
Mine was getting extremely noisy. It was so loud it was hard to use hands free phone.
I decided to fill it up with Shell high cetane diesel and add half a bottle of Amsoil all in one diesel additive…. Wow what a difference it’s very quiet now. I have to turn the radio off to hear the diesel clatter now.
Really love this truck and would be disappointed if an injector failure destroyed the engine….
Good move using the additive and good fuel. Yes, adding cetane really quiets it down and smooths it out. All I generally hear from my Canyon's engine, if I can hear it at all, is a cool intake moan when I roll on some power. I use cheap fuel from a high volume station, but give it a stiff dose of cetane boost and cleaning additive and it runs smooth and quiet.

Plenty of stock trucks have failed too, but good point about tunes stressing what may be a marginal situation. Not all tunes are created equal though. I did my research and made my choice, so far so great. Tuned it with GDE at 10K, running great at 60K. I am more worried about a tootsie roll for a piston pin than the injectors, as my '17 was built during that era.
 

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Good move using the additive and good fuel. Yes, adding cetane really quiets it down and smooths it out. All I generally hear from my Canyon's engine, if I can hear it at all, is a cool intake moan when I roll on some power. I use cheap fuel from a high volume station, but give it a stiff dose of cetane boost and cleaning additive and it runs smooth and quiet.

Plenty of stock trucks have failed too, but good point about tunes stressing what may be a marginal situation. Not all tunes are created equal though. I did my research and made my choice, so far so great. Tuned it with GDE at 10K, running great at 60K. I am more worried about a tootsie roll for a piston pin than the injectors, as my '17 was built during that era.
I wonder if it’s really the wrist pin or a failed piston that leaves the wrist pin only supported on one side.
I don’t understand why GM changed the injectors and pistons from the what was used in the world engine. As in what is used in Australia. They claim it needed to be updated for North America.
I haven’t been able to find piston or injector failures in Australia. One guy was on here saying he had a rod end failure that resulted in an engine replacement..
Not sure how you use yours but mine has had a hard life. I have 50,000 miles and I have towed thousands of miles heavy. Holding it wide open up long hills with over 6k travel trailer behind it.
I have had 8000 lbs construction dump trailer full of hard wood behind it.
I am 64 but still a bad kid at heat and love to get the tail out once in a while. Love that torque…..
I do oil changes, fuel filter ect at 50% but I do run it very hard. I keep telling myself to stop or I am going to end up with an aggressive driving ticket..
 
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