Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Fuel Delivery System
High-pressure fuel lines deliver fuel under extreme pressure from the injection pump to the injectors. This maybe as high as 1600 bar (23, 206 psi). Use extreme caution when inspecting for high-pressure fuel leaks. Fuel under this amount of pressure can penetrate skin causing serious or fatal injury. Inspect high-pressure fuel leaks with a sheet of cardboard. Wear safety goggles and adequate protective clothing when servicing fuel system.
| CONDITION | POSSIBLE CAUSES | CORRECTION |
|---|---|---|
| No Start/Hard Start/Start and Stall | 1. Contaminated Fuel | 1. Drain, Flush and Refill Fuel System |
| 2. Low Fuel Pressure supply to Fuel Filter | 2. Perform the Low Pressure Fuel Pump Test to check the fuel pump pressure of the in-tank electric fuel pump. Refer to FUEL DELIVERY, GAS . | |
| 3. High pressure (tandem) fuel pump | 3. Perform the Tandem Pump Pressure Test Inspect / Replace necessary fuel line(s) | |
| 4. Restricted Fuel Filter | 4. Replace Fuel Filter | |
| 5. Fuel Heater Inoperative | 5. Test Fuel Heater and circuitry | |
| 6. Restricted or Leaking Fuel Lines | 6. Inspect / Replace necessary fuel line(s) | |
| 7. Stored Diagnostic Trouble Codes | 7. Refer to the appropriate Diagnostic Service Information | |
| Stalls Under Aggressive Maneuvers/Loss Of Fuel Pressure | 1. Restricted or Damaged Fuel Pump Lower Filter | 1. Test Fuel Pump Pressure |
| 2. Contaminated Fuel | 2. Drain, Flush and Refill Fuel System | |
| 3. Damaged Fuel Tank | 3. Replace Fuel Tank | |
| 4. Restricted Fuel Filter | 4. Replace Fuel Filter | |
| Cannot Refill Fuel Tank/Excessive Pressure in Fuel Tank When Cap Is Removed | 1. Sticking or Damaged Fuel Tank Fill/Vent Valve | 1. Replace Fuel Tank |
| 2. Restricted or Damaged Fuel Tank Fill/Vent Valve Filter or Hose | 2. Replace Fuel Tank Vent Filter |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.