1. Fuel Tank Issues:
* Empty Tank: The most obvious! Check the fuel level.
* Fuel Filter Issues: A completely clogged fuel filter will prevent fuel flow. Check the filter for blockages and replace it if necessary. Also check for water in the filter (this is common).
* Fuel Tank Debris/Sediment: Sediment or rust in the tank can clog the pickup tube. This often requires dropping the tank and cleaning it.
* Pickup Tube Issue: The tube that draws fuel from the tank to the pump may be clogged, cracked, or disconnected. This requires inspection inside the tank.
* Fuel Shutoff Solenoid (if equipped): Some vehicles have a solenoid that controls fuel flow to the pump. It could be stuck closed or malfunctioning.
2. Lift Pump Issues (if equipped):
* Lift Pump Failure: Many 12-valve Cummins engines have an electric lift pump that helps draw fuel to the injection pump. If this pump fails, you won't get fuel to the injection pump. Check the pump for operation (listen for buzzing/running) and voltage. If it's not getting power, check the fuses and wiring.
* Lift Pump Wiring/Connectors: Check the wiring and connectors for corrosion, loose connections, or breaks.
3. Fuel Lines:
* Clogged Fuel Lines: Fuel lines can become clogged with debris or rust. Inspect the lines visually for damage, kinks, or blockages. If a line is suspect, it may need to be replaced.
* Leaking Fuel Lines: A leak in the lines before the injection pump will prevent fuel from reaching it. Inspect carefully for any fuel leaks.
4. Injection Pump Issues (Less Likely, but Possible):
* Injection Pump Issues: While less likely to cause a complete lack of fuel, a problem *within* the injection pump itself could affect fuel draw. This is more likely to result in poor running rather than a complete lack of fuel to the pump. This is a more complex issue requiring a professional diagnosis.
Troubleshooting Steps:
1. Check the fuel level. This is the easiest and most important first step.
2. Inspect the fuel filter. Replace if necessary.
3. Check for leaks in the fuel lines.
4. Listen for the lift pump (if equipped). If it's not running, check its power supply.
5. Try bleeding the fuel system. This involves opening bleed screws at various points to let air out. There are specific procedures for this – consult a repair manual.
6. If you're still having problems, consult a mechanic specializing in diesel engines. They will have the tools and expertise to diagnose more complex issues.
Remember safety first! Diesel fuel is flammable. Work in a well-ventilated area and avoid sparks or open flames. If you're not comfortable working on your own vehicle, have a qualified mechanic diagnose and repair the problem.
