I have a 1993 chev pick-up v6 4.3, i just installed new spark plugs,new plug wires, distributor cap and rotor button.All plug wires are back in the right position,and i used the firing order 1-6-5-4-3-2 which is right i think , i double checked everything, but now the engine wont start,not sure what to do next everything was fine before i installed the new parts,any info would be greatly appreciated, thanks.

Check the plug connector to the ignition module, it could of disconnected while you were making repairs. Check for spark at the plugs.

This diagram is for 1998-1995 Chevy 6 cylinder 4.3L engines.
Your got the firing order exactly correct, at 1-6-5-4-3-2, but here's the thing to double-check:
The distributor rotation is clockwise (note badly rendered arrow in picture).





Since you probably got everything right, then you're left with really unusual/rare causes of
failure of the ignition system:
(a) rotor button misaligned/failing to make contact?
(b) rotor button not pressed onto distributor shaft far enough therefore failing to provide correct
proximity to distributor cap contacts when coil fires
(c) coil wire or contact loose/disconnected - press coil wire firmly down into distributor cap.
(d) distributor shaft of other damage caused during installation of rotor.
(e) spark plug wires defective from factory
(f) spark plugs defective from factory
(g) battery low - may need a charge to start
(h) ICM (ignition control module) failure - hook up your HEI (high energy ignition) tester, and
watch the quality of the spark on each cylinder.
(i) fuel problem? If spark is being properly delivered, its gotta be a fuel problem...
(j) distributor cap not screwed down flush to top of distributor? maybe just on one side?

Inspect the inside of the distributor cap - if there are lots of little metal bits all over the inside
of the distributor cap, then you know you have a misalignment of some type in there, and the
rotor and cap are destroying each other. normal operation will throw a quota of spark-ed off
metal bits inside the distributor cap, but since your cap is brand new, your attempts to start
the engine should have rotated the distributor so few times, you should see no metal debris.

Inspect the distributor cap contacts to see if any spark marks are more of less in the middle
of the cap's proper "contact zone". If not, you've diagnosed an internal misalignment, which
you know how to correct.

Check rotor and cap sometimes there broken or cracked.