Test Description

The numbers below refer to step numbers in diagnostic procedure.

1. 3
   
   Engine Coolant Temperature (ECT) must be below operating temperature in order to avoid irregular fuel pressure readings due to hot soak fuel boiling.
2. 4
   
   Fuel pressure should be within specified range. If fuel pressure is not within specified range, see FUEL SYSTEM PRESSURE TEST (4.2L) under BASIC FUEL SYSTEM CHECKS (GASOLINE) in BASIC DIAGNOSTIC PROCEDURES - TRUCKS - EXCEPT TRACKER article.
3. 5
   
   Fuel pressure should reach a steady value. If fuel pressure does not stabilize, see FUEL SYSTEM PRESSURE TEST (4.2L) under BASIC FUEL SYSTEM CHECKS (GASOLINE) in BASIC DIAGNOSTIC PROCEDURES - TRUCKS - EXCEPT TRACKER article.
4. 6
   
   If pressure drop value for each fuel injector is within 1.5 psi (10 kPa) of average pressure drop value, fuel injectors are flowing properly. Calculate pressure drop value for each fuel injector by subtracting second pressure reading from first pressure reading. See Figure.