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Discussion Starter #1
I was messin around with my Snap-on 2500 scanner today because I am still having hot start problems and i wanted to see if anything changed on me.

I noticed my TDC offset is -2.02 now. Which i thought was wierd because a year ago when I did the heath reflash, i had my buddy set it with T2 @ -1.94.....Which I later confermed a -5.3 to -5.4 with the 2500 scanner. Which is right on the money as per the MT-2500 values.

The -2.02 tells me that my TDC is lower now? How is this possible? I kinda thought I sorta understood this TDC offset thing...but now I am really confused.

Timing chain stretch? I only have about 9000 miles since reflash.
Does the change in timing indicate a worn IP?

Is any of this info significant?

Need some light shed on me from someone way smarter than me. :D
 

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Okay if that is -2.02 on the MT2500, that would indicate it has retarded itself timing wise for the offset back to GM's stock numbers -.25 to-.75 as would be displayed on a T2 tool.

Before going into a ton of stuff any codes or historical codes, with MT2500 I sometimes have to go to transmission section to see all stored codes, I don't know why but it just is that way.

What is actual & desired timing fully warmed up and idling?
 

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My timing is 12.3.

Time set is 3.5 as normal.

I do have a PO380 code thats been lingering for a year or more, no symptoms..just annoying SES light once a month. Truck starts @ 30 deg in morning.

I just dont understand why My offset would change all of a sudden.

I am also attempting to rule out worn out IP in my hot start problem when I noticed the offset so wacko.

I also notice a clackier sounding engine, but if I have retarted timing somehow, I would guess it would be quieter?

Something starting to slip causing timing gremlins?

I have wiggled, unplugged, smacked, tapped, watered, dryed, heated, cooled, unplugged, plugged everything under my hood twice and nadda.

All the sensors in the data menu on my scanner are in spec. Except TDCO.
 
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