I put a new spider in my 93 s10 blazer 4wd 4.3V6 vinW. While I was at it, on the recomendations on here I pulled the intake and replaced the gasket on it, Thus I had to pull the distributer. Now I have rotated the crank around to the timing mark (there are 2 marks? one is painted so this is the one I am using) I stuck my finger in the #1 spark plug hole to be sure I was on the compression stroke. Replaced the distributer with the rotor pointed at #1 on the cap ( I had to fight the oil pump a little to get it all the way in.). Replaced all the connections plugs and wires,and hooked up my timing light.

Heres the kicker it runs smooth with the timing mark way adc and I mean almost to the right hand side of the balancer. When I turn the distributer to bring the mark to 0 is gets rougher and rougher. when I hit 0 it dies and I cant go bdc at all. [:@]

 

You could be 180 out on the distributer. You could also time via vacum gage and tach. to get the highest vacum with the best idle and let it be.

More than likely the computer has the distributer advanced. I know on my 89 4.3L TBI you need to disconnect the brown wire under the carpet on passenger side. Then time the car normally and reconnect the wire after all is done. You will also throw a code when the brown wire is disconnected but will clear itself. I am not sure if the same is required on a CPI vehical.

 

Yep I have the timing wire under the passenger side carpet disconnected. I am going by the Hayes manual, following it to the T and have also read the label under the hood I am just boggled.

The 0 mark is roughly about 1oclock and it seems to run best with the timing mark between 2and3 oclock.

 

I would start over with the number 1 cylinder at TDC and check the position of the rotor in relation to the number 1 position on the distributer cap. I could be you are off one gear tooth.

 

Chip,
I have the same problem as you--in fact I could not describe it better. I posted on a different forum with no luck. I pulled mine because I had to pull the pass side head for a bad valve. Have you found the problem yet. To me, if the thing is runing wright it can't be out 180! No biggie for me as now I have a rod knock! Let me know what you find in the event I rebuild vs torch.[:@]
PS I also replaced the Nut kit for the intake fuel lines.

 

Ok I had a mechanic from work come over one morning and straighten it out. There are 2 marks on the balancer when you set tdc disregard the first (painted) one and set the unpainted one as tdc. then when you set the timing the painted one is the one you will see with the timing light. Runs like a clock now...be sure to disconnect the ecm there is a plug under the passenger side carpet at the upper edge.