What did you do to your NBS GMT800 Tahoe/Yukon Today?

[iamdub]

I used to think so too, then one time I heard it needs to be done when the balancer is R&R’d and I promptly forgot about doing it. It had already been a year or more since I did the original work. It does state to do it in the manual, which I use alldatadiy for. I have also heard the PCM will do it automatically after a certain amount of mileage but haven’t been able to confirm.

I never considered this. After thinking about it, I bet it has to do with the new pulley not being in the exact same position as the original. This could pull or push the crank a red cünt hair, altering the signal for the CKP.

 

[ratled]

In the continuing process of the 100k/ new to me total service I did the plugs and wires. With a 118k on her I was surprised how soft the wires rubber were and tore just about every one of them getting them off. They were stuck beyond stuck and have to work like a dog with hose pliers just to get them off....... and this was a 1 owner from CA before I got her this last summer.

The most surprising thing was I never had a simple plug and wire change make such a noticeable improvement... from the first cold start to hole shot she really likes her new spark! Looking forward to seeing what the MPG does.

Next up is MAF and throttle body cleaning............

ratled

 

[Fless]

In the continuing process of the 100k/ new to me total service I did the plugs and wires. With a 118k on her I was surprised how soft the wires rubber were and tore just about every one of them getting them off. They were stuck beyond stuck and have to work like a dog with hose pliers just to get them off....... and this was a 1 owner from CA before I got her this last summer.

The most surprising thing was I never had a simple plug and wire change make such a noticeable improvement... from the first cold start to hole shot she really likes her new spark! Looking forward to seeing what the MPG does.

Next up is MAF and throttle body cleaning............

ratled

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I can definitely see the difference in the gap old vs. new.

 

[MADPINTO08]

Finally finished installing LEDs in the back hatch appliques

 

[mountie]

Finally finished installing LEDs in the back hatch appliques
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Looks great ! ( But no lit upper 3rd light ? )

 

[corvette744]

In the continuing process of the 100k/ new to me total service I did the plugs and wires. With a 118k on her I was surprised how soft the wires rubber were and tore just about every one of them getting them off. They were stuck beyond stuck and have to work like a dog with hose pliers just to get them off....... and this was a 1 owner from CA before I got her this last summer.

The most surprising thing was I never had a simple plug and wire change make such a noticeable improvement... from the first cold start to hole shot she really likes her new spark! Looking forward to seeing what the MPG does.

Next up is MAF and throttle body cleaning............

ratled

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Care to share the plugs you used.

 

[corvette744]

I can definitely see the difference in the gap old vs. new.

They are not the same plugs thats for sure electrode insulator tips way shorter on the ones you took out.

 

[MassHoe04]

Don't forget to perofrm a crankshaft variation re-learn in PCM. It is required every time you remove the balancer (unless you marked it and installedd in the same position).

The pulley and crankshaft are not machined with keyway/key? I am new to GM and we know there are some GM-specific quirks and features, but I would expect the removal and install of the harmonic balance pulley to be a fail-proof operation. With the pulleys and cam shafts being indexed with a key/keyway, there is only one position for the pulley which would not even matter if the timing chain/cam/crank were not messed with.

Just wondering... What sensor is taking direct readings indexed from the harmonic balancer?

Like I said, I am new to GM and eager to learn more. But right now, I am trying to wrap my head around why the computer would give a hoot where the harmonic balancer pulley is relative to the crankshaft, if the CPS reads off of the flywheel and timing is unchanged.

Thanks for taking the time to get me up to speed on things related to my "new-to-me" 04 Tahoe!

 

[clandr1]

In the continuing process of the 100k/ new to me total service I did the plugs and wires. With a 118k on her I was surprised how soft the wires rubber were and tore just about every one of them getting them off. They were stuck beyond stuck and have to work like a dog with hose pliers just to get them off....... and this was a 1 owner from CA before I got her this last summer.

The most surprising thing was I never had a simple plug and wire change make such a noticeable improvement... from the first cold start to hole shot she really likes her new spark! Looking forward to seeing what the MPG does.

Next up is MAF and throttle body cleaning............

ratled

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Interesting. What year model is your truck, and what motor does it have? I didn't change my spark plugs and wires until around 200k and can't say I noticed any difference in power, idle smoothness, or fuel mileage (not that I was having any problems, just decided to finally change them out since it was way overdue). I did replace them with new GM OEM spark plugs.

 

[MassHoe04]

Finally finished installing LEDs in the back hatch appliques
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That is cool! Nice job!!!

 

[Rocket Man]

The pulley and crankshaft are not machined with keyway/key? I am new to GM and we know there are some GM-specific quirks and features, but I would expect the removal and install of the harmonic balance pulley to be a fail-proof operation. With the pulleys and cam shafts being indexed with a key/keyway, there is only one position for the pulley which would not even matter if the timing chain/cam/crank were not messed with.

Just wondering... What sensor is taking direct readings indexed from the harmonic balancer?

Like I said, I am new to GM and eager to learn more. But right now, I am trying to wrap my head around why the computer would give a hoot where the harmonic balancer pulley is relative to the crankshaft, if the CPS reads off of the flywheel and timing is unchanged.

Thanks for taking the time to get me up to speed on things related to my "new-to-me" 04 Tahoe!

No the harmonic balancer (pulley) does not have a keyway, never has on any GM V8.

 

[MADPINTO08]

That is cool! Nice job!!!

Thank you!

 

[MADPINTO08]

Looks great ! ( But no lit upper 3rd light ? )

I have it hooked up to my lights didn’t want to do brake lights

 

[mountie]

I have it hooked up to my lights didn’t want to do brake lights

Ahhh..... Makes sense.....

 

[ratled]

Care to share the plugs you used.

Its an '02 GMC Yukon SLT with the 5.3 gaser. I think some of the difference in gap is partly due to the tip wearing/burning off. Hard to tell in the pic but in person the tips really show it.

I used the AC Delco OEM 41-962 plugs and the wires are AC Delco OEM 9748HH. I had a devil of time get the right part numbers. Everyone wanted to sell me "upgraded" or "better" plugs and wires

ratled

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[Fless]

Its an '02 GMC Yukon SLT with the 5.3 gaser. I think some of the difference in gap is partly due to the tip wearing/burning off. Hard to tell in the pic but in person the tips really show it.

I used the AC Delco OEM 41-962 plugs and the wires are AC Delco OEM 9748HH. I had a devil of time get the right part numbers. Everyone wanted to sell me "upgraded" or "better" plugs and wires

ratled

​

Those plugs and wires are exactly what I put in my '04. The plugs are double platinum so they should easily last 60K+ miles. For the way the Hoe gets driven, that'll be over 10 years for me.

 

[SnowDrifter]

I never considered this. After thinking about it, I bet it has to do with the new pulley not being in the exact same position as the original. This could pull or push the crank a red cünt hair, altering the signal for the CKP.

even that, I don't understand?

The pulley bottoms out against the crankshaft. Once that happens, it's essentially "floating" as the only pressure applied would be a result of the belt.

Thrust bearings constrain the crank shaft in the forward/backward direction.

So... Hell if I know

Didn't even know a relearn was needed. I replaced mine while I had some bits apart and can't say I noticed any changes in how the engine behaved

 

[Fless]

Its an '02 GMC Yukon SLT with the 5.3 gaser. I think some of the difference in gap is partly due to the tip wearing/burning off. Hard to tell in the pic but in person the tips really show it.

I used the AC Delco OEM 41-962 plugs and the wires are AC Delco OEM 9748HH. I had a devil of time get the right part numbers. Everyone wanted to sell me "upgraded" or "better" plugs and wires

ratled

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I'd be curious about the plugs that came out, if you still have them. Mfr and part number, and maybe measure the worn gap. The new ones appear to be a different heat range, but they're correct for your application.

 

[ratled]

I'd be curious about the plugs that came out, if you still have them. Mfr and part number, and maybe measure the worn gap. The new ones appear to be a colder heat range, but they're correct for your application.

They are the original from the factory

 

[ivin74]

I never considered this. After thinking about it, I bet it has to do with the new pulley not being in the exact same position as the original. This could pull or push the crank a red cünt hair, altering the signal for the CKP.

I'm still not sure it matters, the pulley is the same (OEM) nothing has changed. It's not like the pulley had a sensor that can read how many times the pulley turns. The service engine has not turned on and don't think it will. How does the engine know that the pulley was swapped out?