1991 Chevy S-10 cranking.

If your saying it won't even crank, I'd check the starter circuit. If it cranks good but won't start, have a helper crank it while you visually check for spark at the plugs, if no spark, I'd check primary voltage at the coil and go from there. If you have spark everywhere, use a gage and check fuel pressure. Some of the national brand auto stores usaed to loan out a fuel pressure gage, if you don't have one. If you have TBI fuel system, use a TBI fuel pressure gage. The gage fittings for TBI and MFI are different. Also, check for any applicable mil codes. If you need specifics on visually checking for spark at the plugs, we'll help you with that? If you need specifics for checking mil codes, we'll help you with that, also. Just let us know. Just a thought, engine cranking, with TBI, you should be able to see injector spray pattern, anything?