Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
1977 Olds 455, HEI, Fitech, GMC Motorhome, no start
Is it possible to keep an eye on injectors/blades while cranking? Maybe they are firing and the engine is getting flooded.
Did you check vacuum/map PID while cranking? If it doesn't change at all, PCM fire injectors with to much fuel.
Maybe a stupid question but here i go. Is the tach line connected to negative coil terminal? PCM "expects" to see a voltage drop from 12v to 0v to fire the injectors.
Try to crank engine with throttle on the floor, so that you can discard a lack of air in air/fuel mixture.
