Fuel System Diagnosis

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

Schematic:

CIRCUIT DESCRIPTION
The Fuel Solenoid Driver is a high current switch which receives inject commands from the PCM. The Fuel Solenoid Driver energizes and de-energizes the fuel control solenoid at precise intervals in order to achieve accurate control of the fuel delivery at all throttle positions and speeds. The Fuel Solenoid Driver supplies ignition voltage to the fuel control solenoid. The Fuel Solenoid Driver also contains circuitry that enables it to sense poppet valve closure, or closure time. This information is transmitted back to the PCM. If the ignition voltage is low, either through faulty connections, charging system failure, low batteries, or after market add-ons, it is possible that a slow closure time will occur. The Fuel Solenoid Driver is located on the right side of the injection pump as viewed from the front of the vehicle. The Fuel Solenoid Driver utilizes a closure ground circuit, an ignition voltage circuit, a fuel inject control circuit and a closure signal circuit.

DIAGNOSTIC AIDS

IMPORTANT: Because it is difficult to diagnosis intermittent conditions, it is critical that every step of the diagnostic table be performed with thoroughness. Since many other failures can cause similar symptoms to that of a failed Fuel Solenoid Driver, the elimination of other, simpler causes of the failure should be eliminated before a Fuel Solenoid Driver is replaced.

It is also important to perform visual checks for a pinched harness at the intake manifold and the turbocharger, and for proper wiring connections at the engine connector. The Fuel Solenoid Driver can be visually checked for an obvious failure. A shorted fuel solenoid driver may cause the ECM I fuse to fail. This type of failure can be associated with a No Start concern. Possible Symptoms of a Fuel Solenoid Driver are:
^ No starts
^ Stalling
^ Intermittent stumble or "fish bite"
^ Surging

An intermittent can be caused by the following:
^ Faulty connections
^ Rubbed-through wire insulation
^ Broken wire inside the insulation

TEST DESCRIPTION
The numbers below refer to the step numbers on the Diagnostic Table.
8. This step will check the ground wire on the injection pump. The wire is located on the top of the pump.
12. This step will determine if proper voltage is going to the fuel solenoid driver.