Engine Block Pressure Testing

Welcome to A to Z Express Mobile Mechanics


   Before the introduction of computerized engine controls, diagnosing a no start condition was very easy. In order the car to start it needs four basics things that never changed. It needs fuel, it needs air, it needs spark and exhaust.

   First thing a technician will check if battery is fully charged and if engine cranks.

  • 12.66 volts = 100% charged

  • 12.45 volts = 75% charged

  • 12.24 volts = 50% charged

  • 12.06 volts = 25% charged

  • 11.89 volts = 0% charged

   If engine cranks but just does not start we need to do a basic checks:

   Checking for spark

While you crank the engine observe if spark is present at the end of ignition wire or ignition coil. 

   Checking for fuel

Connect fuel pressure gage and crank engine to verify that fuel pressure is present and is into manufacture specifications.

   Checking for air

After air filter is removed check the intake manifold for restrictions.