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

[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?