Chart A4A - Fuel System Diagnosis

Fig 1: Chart A4A, Fuel System Diagnosis Schematic

The DFI system requires that fuel pressure be maintained at 9-12 psi and steady under all driving conditions. Fuel Pressure Gauge (J-29658/BT8205) should be attached to fuel line service fitting with Schrader valve fitting from Gauge Set (J-34730-1). This set up will give technician a more precise and more responsive reading.

NOTE: Test numbers refer to test numbers on diagnostic chart.

Fuel pressure should be 9-12 psi and steady. If fuel pressure is not in this range, go to CHART A4B - FUEL PRESSURE OUT OF RANGE.
If fuel pressure drops (leaks down) with key off, either the fuel pressure regulator cannot hold pressure or the fuel pump check ball is not seating. This branch of trouble tree will determine which is causing the fuel pressure leak-down.

Fig 2: Flow Chart A4A, Fuel System Diagnosis

Fig 3: Flow Chart A4A, Fuel System Diagnosis