Q: truck cranks but wont start

Verify that the fuel pump is getting power when you crank the engine. You should have 12 volts at the connector. If not, then the fuel pump circuit has to be diagnosed. Start with the basics. Make sure fuses are good. Check that the fuel pump relay is functioning properly. If those are all good, then sensors and the engine control unit should be checked. For example, the ecu looks for a signal from the crankshaft position sensor when cranking. The crankshaft sensor tells the ecu the position of each cylinder and signals the fuel injectors and ignition coil to fire at the correct moment. If the crankshaft sensor is not functioning properly and not signaling the ecu, the fuel pump and possibly ignition system will not be signaled by the ecu to power up. The ecu itself can also be a cause. If it is not reading signals correctly, it may not respond to any input from any or all sensors involved in making the engine run properly. If you can’t make any progress, have a certified technician look into the no start condition to find the cause.