Engine unable to start but cranks

If the fuel pump is not delivering adequate fuel pressure and volume to the engine, the engine may not start or run properly. Low fuel pressure can cause hard starting, a rough idle, misfiring, hesitation and stalling. No fuel pressure will prevent the engine from starting, or will cause the engine to quit running if the fuel pump fails while driving. Fuel injected engines are very sensitive to fuel pressure as well as fuel volume. Low pressure will cause starting and driveability problems. A pump that can deliver adequate pressure but not enough volume may allow the engine to start and idle normally, but it will starve the engine for fuel and cause a loss of power when the engine is under load, accelerating hard or cruising at highway speeds. Engine Cranks But Will Not Start A dead fuel pump can prevent an engine from starting, but so can a problem with the ignition system or the engine itself (such as a broken timing belt). The first thing to check would be spark. This can