Pinpoint Tests HC: Fuel Delivery System: Introduction
WARNING:
To prevent the risk of high-voltage shock, always follow precisely all warnings and service instructions, including instructions to depower the system. The high-voltage system utilizes approximately 300 volts DC, provided through high-voltage cables to its components and modules. The high-voltage cables and wiring are identified by orange harness tape or orange wire covering. All high-voltage components are marked with high-voltage warning labels with a high-voltage symbol. Failure to follow these instructions may result in serious personal injury or death.
WARNING:
Do not work on the fuel system until the pressure has been released and the engine has cooled. Fuel in the high-pressure fuel system is hot and under very high pressure. High-pressure fuel may cause cuts and contact with hot fuel may cause burns. Failure to follow these instructions may result in serious personal injury.
WARNING:
Before working on or disconnecting any of the fuel tubes or fuel system components, relieve the fuel system pressure to prevent accidental spraying of fuel. Fuel in the fuel system remains under high pressure, even when the engine is not running. Failure to follow this instruction may result in serious personal injury.
WARNING:
Do not smoke, carry lighted tobacco or have an open flame of any type when working on or near any fuel-related component. Highly flammable mixtures are always present and may be ignited. Failure to follow these instructions may result in serious personal injury.
WARNING:
Do not carry personal electronic devices such as cell phones, pagers or audio equipment of any type when working on or near any fuel-related component. Highly flammable mixtures are always present and may be ignited. Failure to follow these instructions may result in serious personal injury.
WARNING:
When handling fuel, always observe fuel handling precautions and be prepared in the event of fuel spillage. Spilled fuel may be ignited by hot vehicle components or other ignition sources. Failure to follow these instructions may result in serious personal injury.
WARNING:
Clean all fuel residue from the engine compartment. If not removed, fuel residue may ignite when the engine is returned to operation. Failure to follow this instruction may result in serious personal injury.
This pinpoint test is intended to diagnose the following:
- chassis components
- engine vacuum
- fuel pressure
- fuel supply line
- fuel supply
- fuel filter
- fuel injector (9F593)
- fuel pump (9H307)
FUEL SYSTEM SPECIFICATION CHART (IGNITION ON, ENGINE OFF VALUES)
| Fuel System Type | External Pressure Gauge |
|---|---|
| MRFS | 350-450 kPa (51-65 psi) |
Fuel System Type Definitions:
Mechanical Returnless Fuel System (MRFS): Fuel pressure is controlled by a mechanical pressure regulator located on the fuel pump module in the fuel tank. Some vehicles use a fuel pump control module to control the fuel pump module at low and high speeds.
Harness Side
| Circuit | Pin |
|---|---|
| FPRTN (Fuel Pump Return) | 4 |
| FPPWR (Fuel Pump Power) | 5 |