i have a 93 blazer with a 95 4.3L engine was running rough and dying at an idle when cold with check engine light on when it got up to temp it would smooth out and the light would go out then one day it died again whille idling and wouldn't start again after numerous attempts to start smoke came out from around distributor area. Had to have truck towed home. took plenum off found washing on passenger side replaced fuel regulator and found broken vacuum hoses and replaced. still wouldnt start found no spark at coil replaced coil (had msd when i got it) still nothing, replaced pick up coil, icm tested ok. when putting distributor together did 180 out oops. tried starting it before i figured it out. tore distributor back out fixed and replaced icm on advice of a friend. truck started couple of times figured i had timming all off tried adjusting timming like u would on a non computer car big oops after 3 tries smoke again no spark at coil, pulled valve cover off rotated engine till both rocker arms were loose to get tdc( tried using dampner but mine free spins is that normal?) replaced pick up coil and icm again put it all back together and still nothing. i have also replaced tempature sensor, plugs and wires, (did gap the plugs) rotor and cap. really dont have the funds to shotgun this thing anymore than i have does anybody have any ideas.

 

no this is not normal. sounds like key steal is broke or missing.

since you have the valve covers off. to get TDC
DISCONNECT COIL
1 remove the spark plug on #1,
2 watch the intake valve,
3 rotate engine (removing all plugs will help a lot)
4 when the intake valve closes the piston should be at the bottom
5 rotate the engine until piston comes to top on compression stroke
( you can put a small paper wad where plug goes and the piston should shoot it out just don't pack it tight.)
6. insert a plastic straw or something into spark plug hole to tell when piston is at top. do NOT use metal as it may hurt piston or foul.

This can be done with out taking valve covers off.
You can use your thumb over plug hole

hope this helps

Headache

 

Thank you for your help. Tore everything apart and found outer ring was slipping on dampner. Drove all over town and finally found a new one. Now I can't get it to slip on to the crank shaft.