ok so this is the layout supposedly for my 1998 blazer 4wd, and the firing order is 1-6-5-4-3-2




so when 1 is firing both valves are closed, but what is 6 doing at this time,

would it also be in the closed position at this time, I have two choices for top dead center either of the 360 turns in 720. One of my options looks like this where cylinder 6 looks like exhaust is open. So Im not sure if it would be like this or in my other option.

option 1



or is it option 2 for TDC, where nothing is really going on in that bank.

 

When #1 is at TDC on the compression stroke, #4 will be at TDC on the exhaust stroke. #6 will be coming up on the compression stroke (next to fire), so the valves will be closed, but the piston will not be at TDC. I'm not sure if that answers your question because I'm not sure what you're asking.

 

Thanks Tom, its so hot today, but I think I got it and will do it tonight.
I tried plugging cylinder one to test for compression but got a fair amount of compression on both rotations. I think its easier to just look at the valves and Ill follow what you said about cylinder 4 as well.

 

Good luck!