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

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iamdub

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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

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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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Fless

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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.
 

corvette744

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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.
 

MassHoe04

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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

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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

View attachment 361007

View attachment 361008

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.
 
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