Hi. i have a 1994 s10 blazer and it will not start for anything. i changed the injectors and the fuel pump, spark plugs are fine and tubes are in the right posisioon, do you know what it could be.

Anytime a car wont start its missing one of the key things it needs to start. Air, Fuel, spark or compression. The first thing to check is to pull a wire off the spark plug and put a screw drive in the end of the wire. Lay the screw driver on the engine near metal. Crank it and look for a large blue spark it should make a nice popping noise.
If no spark try the same thing with the coil wire. If spark its the cap or rotor. No spark its the coil or module.
If the plugs have spark, try pouring a small amount of gas in the throttle body and see if that starts it. If it does, fuel problem check filter and pump.
If it wont start with either or gas in the throttle body and the plugs have spark then it is either a timing or compression issue. Remove the plug wire from the center of the distrib cap and then remove the cap making sure no wires come off. Have someone crank the engine and see if the rotor spins. If it does not you need to replace the timing chain/belt. If it does spin rent a compression checker and check each cylinder.

Hope this helps.