Test Description

The numbers below refer to the step numbers in the diagnostic procedures.

1. 3
   
   The Engine Coolant Temperature (ECT) must be below the operating temperature in order to avoid irregular fuel pressure readings due to hot soak fuel boiling.
2. 4
   
   The fuel pressure should be within the specified range. If the fuel pressure is not within the specified range, see FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4.6L DEVILLE & SEVILLE article.
3. 5
   
   The fuel pressure should reach a steady value. See FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4.6L DEVILLE & SEVILLE article.
4. 6
   
   If the pressure drop value for each fuel injector is within 1.5 psi (10 kPa) of the average pressure drop value, the fuel injectors are flowing properly. Calculate the pressure drop value for each fuel injector by subtracting the second pressure reading from the first pressure reading.