Why is a Car cranking but not starting?

Fuel pump gone bad? Relay stuck? Ignition module fried? Only two things will keep an engine from starting. Lack of fuel or lack of spark. The first step is to determine if spark is present by detaching a plug wire and carefully inserting a screwdriver or the like into the end and placing close enough to the engine block (metal) without touching it (1 inch or less) for a spark to jump. Have someone crank the vehicle and look for spark. If no spark then you have found the culprit. Bad coil or ignition module. CAUTION! You can get quite a jolt if you handle the wire while the car is being cranked. If you have spark then you need to determine if you have a working fuel pump. One method is to have someone turn the key from the off position to the run position (the position where the engine runs {just before the crank position}) a few times while you listen as closely to the fuel tank as you can get. You will hear the buzzing of the fuel pump if it is functioning. The other method is to locate the fuel line pressure hookup (it will be on the fuel rail. a valve not unlike a tire valve only larger) and depress the valve stem. It WILL SHOOT FUEL AT YOU. SO BE CAREFUL. Once you have done this cycle the key a few times and then depress the valve again. If it spits at you again the pump is circulating fuel, if not then the pump is not functioning. Y-THINK-Y Well i would check the spark at the plug first. You have to eliminate spark and fuel problems. If you turn the key you should hear you fuel pump engage. That doesn't necessarily mean that it's working. Once you know that the fuel is getting to the motor there are 3 things that I would check. 1. Crankshaft sensor (located on the transmission housing) 2. Camshaft indicator (located on the side of the block) 3. Ignition coil. (where all the plugs come from) The first two provide information to the PCM and if it doesn't get it the van will not start. It would help if I knew what year and model'engine size ----------------------------------------------------------------------------------- I certainly agree that these other sensors can be the cause but unfortunately to determine the source of problem beyond the simple spark or fuel tests it is best to have a diagnostic computer because there is so many little telemetric devices that will effect the computer that one could spend many, many hours and dollars replacing them one-by-one. This is when a pro should come into the picture. POST: It is my experience that an engine will not 'crank' at all if the crank sensor is bad. Y-THINK-Y