Hey Guys,

I am trying changing out the timing chain on my 1999 Blazer, 4x4, Auto, 169k miles.

I begin this odyssey trying to solve a P1345 error. I replaced the cam timing sensor, to no avail then I checked the timing chain and discovered too much play. Now I am assembling the replacement chain and sprockets and I am having issues.



I rotated the camshaft until the mark aligned with the balance shaft mark.



I put the camshaft sprocket in place, just like in illustrations, and the timing mark points to 6pm, or the crankshaft sprocket mark.




So far everything looks good, but when I align the harmonic balancer… the two timing marks are off, like way off.


The harmonic balancer is off, by nearly 180 degrees….

How have I screwed this up?

How can I be at TDC for #1 or #4 ?

Should both timing marks, the camshaft sprocket and crankshaft sprocket, be pointed down at at 6pm?


The camshaft dot has been moved, and is at high noon.