* Glow Plug System: This is the most likely culprit. Diesel engines need the glow plugs to heat the air in the cylinders to a temperature that allows the fuel to ignite. If the glow plugs are faulty, or the glow plug relay/controller is malfunctioning, the fuel won't ignite. Check the glow plugs themselves (resistance testing is ideal), the relay, and the wiring for shorts or breaks. Listen carefully for the glow plug cycle (a clicking sound for a few seconds before cranking).
* Injection Pump Timing: If the injection pump is out of time, the fuel will be injected at the wrong moment in the engine's cycle, preventing ignition. This is more complex and usually requires a mechanic with specialized tools.
* Injection Pump Issues: The injection pump itself could be failing. It might not be delivering fuel at sufficient pressure, or the timing within the pump could be off. This needs professional diagnosis.
* Compression: Low compression in one or more cylinders will prevent starting. This requires a compression test to diagnose. Worn rings, valve problems, or head gasket failure are common causes.
* Fuel Delivery Problems (despite thinking you have fuel): While you say it's getting fuel, verify this. Is the fuel filter clogged? Is the fuel shutoff solenoid working correctly? A blockage after the filter could still prevent fuel from reaching the injectors.
Troubleshooting Steps:
1. Verify the Glow Plug System: This should be your first step. Test the glow plugs for proper resistance using a multimeter (check your owner's manual or online resources for the correct resistance values). Listen for the glow plug cycle.
2. Check the Fuel System (again): Bleed the fuel lines if needed. Inspect the fuel filter for blockage and change if necessary.
3. Compression Test: If the glow plugs seem fine, get a compression test done. This will definitively tell you if you have adequate compression in each cylinder.
4. Injection Pump: This is the most involved and expensive potential problem. If the previous checks don't reveal the issue, professional help is strongly recommended.
Important Note: Attempting some of these fixes (especially involving the injection pump) can be dangerous if you're not familiar with diesel engines. If you're not comfortable working on your vehicle yourself, it's best to take it to a qualified mechanic specializing in diesel engines. They have the tools and expertise to diagnose the problem accurately and efficiently.
