99 Blazer new distributor timing

[TCGrove]

I have a 99 Chevy Blazer 4x4 with 158,000 miles on it. I just replaced the intake manifold gasket and the distributor. I marked the old and new distributors, but it still ended up off a tooth or two. I ended up starting from scratch. Removed #1 plug, found TDC (matched timing mark), installed distributor button to the (6) mark on the distributor, and reassembled everything. It started right up and runs good. My question is: Do I need to check the timing and if so, how? I read somewhere "after you get it started and running the camshaft retard needs to be set with a good engine capable scanner." Is this the case? Should I just check it with a timing light and if so what is the setting?
Does the ECM just correct the timing?

I thought I would add a couple things to this. I'm guessing "if it ain't broke, don't fix it" as far as the timing adjustment. I've now driven it a 100 miles and it runs great. Also, I replaced the distributor because I had broken the little tab that holds the cap on a few years ago. I was using a c-clamp to hold it on. The old distributor gear teeth were noticiably worn. They were almost sharp to the edge, where the new gear had squared off tips and a much tighter fit.

[blazes9395]

If you don't have a service light on and it was installed using the directions provided here, or in the service manual, your fine, no further adjustment is needed. Timing is controlled by the ECm from this point.

[MT-2500]

Originally Posted by TCGrove

I have a 99 Chevy Blazer 4x4 with 158,000 miles on it. I just replaced the intake manifold gasket and the distributor. I marked the old and new distributors, but it still ended up off a tooth or two. I ended up starting from scratch. Removed #1 plug, found TDC (matched timing mark), installed distributor button to the (6) mark on the distributor, and reassembled everything. It started right up and runs good. My question is: Do I need to check the timing and if so, how? I read somewhere "after you get it started and running the camshaft retard needs to be set with a good engine capable scanner." Is this the case? Should I just check it with a timing light and if so what is the setting?
Does the ECM just correct the timing?

I thought I would add a couple things to this. I'm guessing "if it ain't broke, don't fix it" as far as the timing adjustment. I've now driven it a 100 miles and it runs great. Also, I replaced the distributor because I had broken the little tab that holds the cap on a few years ago. I was using a c-clamp to hold it on. The old distributor gear teeth were noticiably worn. They were almost sharp to the edge, where the new gear had squared off tips and a much tighter fit.

quote
I read somewhere "after you get it started and running the camshaft retard needs to be set with a good engine capable scanner.
quote
I bet I said that a 100 times.
The reason for that the camshaft retard needs to be as close to 0 degrees - or + as you can get it.
It can be off some and not set the check engine light.
It needs to be set so the rotor lines up with the spark plug terminal to keep from burning rotor and cap and to keep ign from building up to much high voltage from coil to spark plugs.
High voltage to spark plugs can lead to ign and engine damage.

As Blazes9395
Said timing is controlled by VCM/pcm computer system.
You can not time with a timing light now days like the older ones.
The VCM sets timing and corrects and adjusts timing to engine load.

Also turning the dist all day will not change engine timing.