My 91 s10 4x4 4.3 turns over no start has spark good fuel presure but no fuel coming out of injectors pore case down carb.wants to run. Had bad i.c.m. but replaced with good one .and new computer

check and test fuel pump -fuel filter

you have to get the fuel pump checked.

Could be your injector circuit is the problem. Check if injectors have power to them with key in on, not start. Each injector has a common hot wire and a ground that goes into the computer for internally grounding the injector circuit, and consequent pulsing of the injectors. There should also be an injector fuse, so check that if circuit has no power to the injectors.
At a parts store, you can buy a very cheap injector circuit tester called a "noid light". You just plug it into the injector connector and crank the engine over. If circuit is good, the noid light will be blinking. If no blinking light, either the power side or the ground side is the problem. If you have power to the injectors, it must be the ground side has a problem-common for wiring to get too close to a hot exhaust part and melt the wiring.

injector relay in the engine fuse box. or the fuse. check these.

Be more explicit.
How the spark plugs looks like? Are them black?

I have seen two different problems with symptoms like this. 1. A leaking injector. If one of the injectors is leaking a small amount through the pintle on the end of the injector it will bleed the fuel system presure off and dribble fuel into the cylinder, fouling that cylinder. When you try to start it the fuel that has pooled into the manifold will create smoke when it does start. And since the fuel pressure has bleed off to zero PSI in the fuel supply lines it will need time for the fuel pump to recover the system up to normal operating presure. Presure testing (bench test) of the injectors is needed to verify this. 2. A bad fuel pump, relief valve, or bleed-back check valve will bleed the fuel system presure off while it is sitting. To find out if this may be the problem a fuel presure guage set needs to be installed and then run the engine, verify the operating presure is normal, and then shut the engine down and watch the fuel pressure for exessive drop.

The leaking injector is more apt to create the smoke when it fires up, but both can cause this. I would start with check #2 first. Of course there are many other things that can cause symtoms like this but these 2 are the most likely causes.

Hope this helps, if you have any further questions just ask!

check fuel presure and replace fuel pump if needed

Sounds like a vapor lock situation.

First check and see how close your fuel lines are the any heat producing elements such as the intake, exhaust manafolds or pipes, ect.. also check the fuel take presure regulator and fuel cap. if there are leaks this will also have the same effect.

If vapor lock is the case a cheep simple quick fix is to simply wrap the lines with some material like header wraps.

Are you getting spark? If not, check if the distributor is turning when cranking the engine. If it is, check for power at the coil, if you've got power at coil it probably the ign module. Common on those years. If you have spark and good fuel pressure check compression. One small possiblily is the coolant temp sensor is bad causing the injectors to flood the engine, in which case you can hold the gas pedal to the floor while cranking to turn off the injectors. Good luck!

2 things come to mind.. Fuel pressure regulator.. and Leaking injectors..