GM-GMC: Wont start, belts and pulleys, electrical connector

Question
i have got an 89 GMC 4WD, 2500 that wont start.  It turns over but will not fire.  It act as if there is no gas.  I have tried putting gas down the carb and will fire once or twice but that is it. What could be wrong with it?

Answer
Use a flashlight and have a look down the throttle body throat while someone cranks the engine over.  Watch out for moving belts and pulleys.  If there is gas being sprayed you may want to look at whether you have spark or not.  If you don't have fuel, see if you can access the fuel pump electrical connector and check for power and ground.  If you have power and ground, could be a faulty pump.
Hope this helps