1. Fuel injector pump issues: The fuel injector pump (IP) is responsible for delivering fuel to the engine's cylinders. When the IP is warm, it can lose some of its ability to create pressure, which can prevent the engine from getting enough fuel to start.
2. Fuel return lines: The fuel return lines are responsible for carrying excess fuel back from the IP to the fuel tank. If the return lines are damaged or blocked, they can restrict the flow of fuel to the IP, which can also prevent the engine from starting.
3. Glow plugs: The glow plugs are responsible for heating the engine's combustion chambers, which helps the engine to start when it is cold. If the glow plugs are not working properly, the engine may not be able to reach the necessary temperature to start.
4. Injection timing: Incorrect injection timing can prevent the engine from getting the fuel it needs at the right time, which can prevent it from starting.
5. Electrical issues: A variety of electrical issues, such as a failed starter solenoid or a faulty fuel shut-off solenoid, can also prevent the engine from starting.
If you are experiencing problems with your 1993 GMC 6.5 diesel engine not starting when warm, it is important to have it diagnosed by a qualified mechanic. They will be able to identify the specific cause of the problem and recommend the necessary repairs.
