the engine cranks and cranks, will not start
engine cranks easily, won't start on 1990 GMC 1500 Pickup
Engine cranking shows the battery and starter are good. The engine needs three things to start, fuel (gasoline), ignition (spark) and mechanical integrity (it must develop compression in each cylinder to start ie mechanical components must be in synchronization with each other. If it had run well previous to this no start condition chances are the engine is well mechanically. Had the Check Engine light been on? The engine may have lost spark or fuel which could be due to any one of a number of sensors having failed or the fuel pump or related components are not delivering fuel to the fuel injectors. The engine uses many sensors to report engine temperature, air flow into the engine, crankshaft and crank shaft position sensors to allow the computer in your car to make calculations controlling fuel and spark to the cylinders. It is hard to speculate without being able to hear the engine crank over and do some preliminary tests to determine the cause of your no start condition.