Table A-5 Fuel Injector Circuit Check (Engine No-Start)

Table A-5 Fuel Injector Circuit Check (Engine No Start) (1 Of 2):

Table A-5 Fuel Injector Circuit Check (Engine No Start) (2 Of 2):

Fuel Injector Circuit:

CIRCUIT DESCRIPTION

The Engine Control Module (ECM) controls each individual injector by providing a ground, this system is referred to as Sequential Multiport Fuel Injection (SFI). When the ignition switch is turned to the "ON" or "START" position (engine running), the ECM will energize/de-energize the fuel injector solenoid coil. With this coil energized, a plunger is activated, allowing pressurized fuel to be sprayed through the fuel injectors into the combustion chamber where it is mixed with air from the intake manifold, thus creating the proper air/fuel mixture needed for combustion.

DIAGNOSTIC AIDS

Water or foreign material in the fuel can cause a no start or lack of power condition. Low fuel pressure, a restricted fuel filter or fuel injectors may also cause a no start condition.

There may be fuel spray at the fuel injectors, but it may not be enough to start the engine. If the fuel injectors and their circuit are OK, and fuel spray is detected, the fuel injector nozzle may be partly blocked or restricted.

An intermittent malfunction may be caused by a poor connection, rubbed through wire insulation, or a wire broken inside the insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connections before component replacement.


TEST DESCRIPTION

Number(s) below refer to the step number(s) on the Diagnostic Table.


1. The Engine OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

2. If a fuse is found to be the cause of the no start, locate and repair any shorts that may have caused the fuse to blow before replacing the fuse.

4. After one minute from the time the fuel pump stops running the fuel pressure should drop and hold to approximately 180 kPa (25 psi).