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 compression TDC for #1 or #4 ?



Should both timing marks, the camshaft sprocket and crankshaft sprocket, be pointed downwards to 6pm?





Thanks,
J

 

Harmonic balancer should be off by exactly 180 degrees. It doesn't matter (dots both together or dots both up on cam and crank gears) as long as you drop the distributor in with the rotor pointing to the correct position. It's really true! I think putting the dots together is easier to read.

This is a 4-stroke engine. 2 revolutions of crank to get a cylinder into firing position. One revolution of camshaft to do the same. One revolution TDC#1, the next TDC#4, then next TDC#1, and so forth.

p.s. timing gears would not be the cause of a P1345 in a running engine.