What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[DaRosa218]

Then tell us how genuine ACDelco plugs “went to shit” in a few months. This is actually the first time I’ve heard of this happening. As in ever. Fill in the details, as in exactly what went to shit means and any other abnormal conditions, because they’re without a doubt the best plugs made for our vehicles. Nearly everyone here runs them, most for years on the same set, without a problem. Did you attempt to gap them by any chance?

Could be a plethora of things that caused it in my opinion; faulty sensor, bad batch of fuel as I had pre-ignition just before loss of performance, etc.

What I meant by went to shit is that they fouled out, which is odd. I'm not knocking AC Delco's all I am saying is that they went bad in 6 months which is unusual compared to all of my past experiences. I know a lot of members use them, hell I used them plenty of times over the years in my past LS powered vehicles.

I did not try to re-gap them, you'll break the tip which everyone should know not to even attempt to re-gap Iridium plugs. I'm not a rookie or shade tree mechanic when it comes to these LS motors for the most part, I've been a very active member on here giving advise since 2010 so I get it when you say they are "the best for our trucks" LOL.

But to answer your question, I have a rough idle and poor performance after a bit of pre-ignition while WOT on a back road. i immediately backed out of it and pre-ignition went away. I went home and hooked the Yukon up to my Tech 2 wanna be scanner and got a Bank 1 Rich Code despite not having a DTC on the dash. I pulled 2 plugs from both banks and they are fouled out.

All new AC Delco 02 sensors, AC Delco map sensor, Delphi MAF sensor, Duralast knock sensors in the last 2 months. Plug wires were replaced with new AC Delco's when I changed the 41-110 Delco's 6 months ago. I swear by their plugs and parts, that's why I was baffled...

Replacing the plugs with NGK's then going to diagnose further if no change. A few buddies run TR55's in their Trailblazer SS's and swear by them

 

[Rocket Man]

Could be a plethora of things that caused it in my opinion; faulty sensor, bad batch of fuel as I had pre-ignition just before loss of performance, etc.

What I meant by went to shit is that they fouled out, which is odd. I'm not knocking AC Delco's all I am saying is that they went bad in 6 months which is unusual compared to all of my past experiences. I know a lot of members use them, hell I used them plenty of times over the years in my past LS powered vehicles.

I did not try to re-gap them, you'll break the tip which everyone should know not to even attempt to re-gap Iridium plugs. I'm not a rookie or shade tree mechanic when it comes to these LS motors for the most part, I've been a very active member on here giving advise since 2010 so I get it when you say they are "the best for our trucks" LOL.

But to answer your question, I have a rough idle and poor performance after a bit of pre-ignition while WOT on a back road. i immediately backed out of it and pre-ignition went away. I went home and hooked the Yukon up to my Tech 2 wanna be scanner and got a Bank 1 Rich Code despite not having a DTC on the dash. I pulled 2 plugs from both banks and they are fouled out.

All new AC Delco 02 sensors, AC Delco map sensor, Delphi MAF sensor, Duralast knock sensors in the last 2 months. Plug wires were replaced with new AC Delco's when I changed the 41-110 Delco's 6 months ago. I swear by their plugs and parts, that's why I was baffled...

Replacing the plugs with NGK's then going to diagnose further if no change. A few buddies run TR55's in their Trailblazer SS's and swear by them

Fair enough. Report back after some time. I run NGK TR6’s in my 02 6.0 because they’re spec’d by Blackbear for my supercharger tune. They’re one range colder than stock to avoid predetonation due to boost.

 

[DaRosa218]

Fair enough. Report back after some time. I run NGK TR6’s in my 02 6.0 because they’re spec’d by Blackbear for my supercharger tune. They’re one range colder than stock to avoid predetonation due to boost.

Will do Brother, I wish mine was boosted.... Some day, lol.

 

[PPV12HOE]

Could be a plethora of things that caused it in my opinion; faulty sensor, bad batch of fuel as I had pre-ignition just before loss of performance, etc.

What I meant by went to shit is that they fouled out, which is odd. I'm not knocking AC Delco's all I am saying is that they went bad in 6 months which is unusual compared to all of my past experiences. I know a lot of members use them, hell I used them plenty of times over the years in my past LS powered vehicles.

I did not try to re-gap them, you'll break the tip which everyone should know not to even attempt to re-gap Iridium plugs. I'm not a rookie or shade tree mechanic when it comes to these LS motors for the most part, I've been a very active member on here giving advise since 2010 so I get it when you say they are "the best for our trucks" LOL.

But to answer your question, I have a rough idle and poor performance after a bit of pre-ignition while WOT on a back road. i immediately backed out of it and pre-ignition went away. I went home and hooked the Yukon up to my Tech 2 wanna be scanner and got a Bank 1 Rich Code despite not having a DTC on the dash. I pulled 2 plugs from both banks and they are fouled out.

All new AC Delco 02 sensors, AC Delco map sensor, Delphi MAF sensor, Duralast knock sensors in the last 2 months. Plug wires were replaced with new AC Delco's when I changed the 41-110 Delco's 6 months ago. I swear by their plugs and parts, that's why I was baffled...

Replacing the plugs with NGK's then going to diagnose further if no change. A few buddies run TR55's in their Trailblazer SS's and swear by them

Those duralast knock sensors are gonna be a regret sooner or later... I can't begin to count the number of aftermarket knock sensors I've had to pull intakes off and replace after others have just put them in...
I always tell people it's not worth the work to put in something cheaper than the A/C Delco sensors... I also always replace the harness as well...
This is just my humble opinion...

 

[DaRosa218]

Those duralast knock sensors are gonna be a regret sooner or later... I can't begin to count the number of aftermarket knock sensors I've had to pull intakes off and replace after others have just put them in...
I always tell people it's not worth the work to put in something cheaper than the A/C Delco sensors... I also always replace the harness as well...
This is just my humble opinion...

Knock sensors are not under the intake for my Gen IV LY6, they're mounted on the sides of the engine block. Easy to access and came with a lifetime warranty if they fail so I wasn't stressing it. The earlier Gen III Vortec's are under the intake and agreed, ONLY run Delco knock sensors and replace the wiring harness

 

[PPV12HOE]

Knock sensors are not under the intake for my Gen IV LY6, they're mounted on the sides of the engine block. Easy to access and came with a lifetime warranty if they fail so I wasn't stressing it. The earlier Gen III Vortec's are under the intake and agreed, ONLY run Delco knock sensors and replace the wiring harness

I skipped right over your having a 6.0 LY6... my bad...

 

[DaRosa218]

I skipped right over your having a 6.0 LY6... my bad...

No worries Brother, you were looking out and appreciate that

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[R3cord303]

Fair enough. Report back after some time. I run NGK TR6’s in my 02 6.0 because they’re spec’d by Blackbear for my supercharger tune. They’re one range colder than stock to avoid predetonation due to boost.

I would like to run a range colder and one tick larger gap for my cammed application. I just dont know how part numbers work so I haven’t looked into it yet

 

[avalonandl]

Ordered a set of NGK TR5IX, AC Delcos crapped out after 6 months of use [emoji2959]

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Wow- which AC's ? Mine lasted 134k- they were OEM when I bought the Denali. Is it possible you ended up with a set of counterfeit AC if you bought them online? The AC Platinum should last 75k miles.

 

[lowh07]

No matter how much power your battery or booster box or other battery from someone jumping you off has, it's not going where it needs to if the circuit is weak. Check the heavy ground cables and positive cable going to the starter for corrosion.

For the extended cranking issue, it sounds like the fuel system is losing it's prime. It's either a fuel pressure regulator or the check valve in the fuel pump module. Common problem.

It was completely toast by the time I attempted to start it last night. No power anywhere. Going to check the cables today