Kick-Starting A Diesel Engine With Zero Fuel Pressure

If your diesel engine has run out of fuel, you should not try to start the engine as injectors and other parts could be damaged due to a lack of lubrication. The first step is to add fuel, and then bleed the lines and injectors. This can be done by loosening the bleeder or union nuts a few turns without removing them, and then using a compressor to pump air into the fuel system via the filler neck. Once all the air is out of the fuel system, tighten the bleeder and attempt to start the engine. Newer vehicles are more self-serving when it comes to the priming process, and you can prime the fuel system by turning the ignition on for 30 seconds without starting the engine.

Check the glow plugs and intake heater

When your diesel engine won't start, it's important to check the glow plugs and intake heater, especially if it's during the cold weather season. Glow plugs are essential for ignition in diesel-powered engines, as they heat the air-fuel mixture in the engine, making it easy to ignite under compression. Here are some detailed steps to help you check the glow plugs and intake heater:

Check the Glow Plugs:

• Understand the Basics: Know that glow plugs are heating devices that use a heating element to heat the air in the diesel engine, enabling combustion and ignition. They are crucial for starting a diesel engine in cold weather.
• Recognize Symptoms of Failing Glow Plugs: Some common signs of failing glow plugs include difficulty starting the engine when cold, uncombusted fuel in the exhaust soon after startup, rough engine running after startup (especially at idle), and excessive smoke during startup.
• Use a Multimeter to Test the Glow Plugs: You can use a digital multimeter to test the resistance and voltage of the glow plugs. First, locate the glow plugs in your engine, which can vary depending on the make and model of your vehicle. Consult your manufacturer's handbook for the exact location. Remove any caps or connectors from the glow plugs. Clean and inspect the connector and pins for any signs of rust, corrosion, or looseness.
• Set Up the Multimeter: Set your multimeter to the Ohms setting (denoted by the omega symbol, Ω). Connect the multimeter's leads together and record the resistance value. This step helps calibrate the multimeter.
• Test Battery Voltage: Put the multimeter in DC Volt reading mode. Check the voltage of your car battery by placing the negative lead on the negative terminal and the positive lead on the positive terminal. Ensure the readings are close to 12.5 Volts when the car is off and 13 Volts when running.
• Connect the Multimeter to the Glow Plugs: Connect the negative lead of the multimeter to a ground point in the engine, which can be found by following the wire from the negative battery terminal or the alternator into the engine wall. Then, connect the positive lead to the top of the glow plug.
• Evaluate the Multimeter Reading: Refer to your shop manual to determine the acceptable resistance range for glow plugs in your vehicle. Typically, it should be no more than 6 Ohms. If a glow plug shows a higher resistance, it may need replacement.
• Replace Faulty Glow Plugs: If one or more glow plugs show unusually high resistance, consider replacing them. It is recommended to replace all the glow plugs simultaneously for optimal performance.

Check the Intake Heater:

The intake heater is another component that aids in cold starts for diesel engines. While glow plugs heat the air in the cylinder, the intake heater warms up all the air entering the engine, making it a more effective solution in extremely cold conditions. Some vehicles, like the Duramax, use both systems for maximum efficiency. If your vehicle has an intake heater, ensure it is functioning properly during the cold season. Consult your vehicle's handbook for specific maintenance instructions.

Get new batteries

Getting new batteries for your diesel truck is a straightforward process, but it's important. Diesel trucks have two batteries to start the engine and heat the glow plugs. If your batteries are in poor condition, it can affect the quality of the glow plugs, flood the engine, and run down the batteries to the point that your engine won't start. Here are some tips to help you get new batteries:

• Consult a professional: While you can replace the batteries yourself, it's always a good idea to consult a diesel expert or a mechanic. They can guide you in choosing the right battery for your specific truck model and ensure optimized performance and compatibility.
• Consider your requirements: Diesel truck batteries come in various styles, each addressing certain requirements for optimal performance and longevity. For example, if you operate your truck in harsh weather conditions, you'll need a battery that can withstand extreme temperatures.
• Prioritize key features: When choosing a new battery, prioritize features like higher life cycles, durability, and advanced safety features. Look for batteries with spill-free technology, vibration resistance, and a long lifespan.
• Opt for reputable brands: Go for well-known brands that offer reliable products. Some popular options include XS Power, Optima, Odyssey, and ACDelco. These brands offer features like AGM spill-free technology, dense glass mat separators, spiral cell technology, and extended warranties.
• Check compatibility: Not all diesel truck batteries are created equal. Ensure the battery you choose is compatible with your truck's engine and electrical system. Consult your truck's manual or seek advice from a professional to avoid issues like excessive stalling, vehicle shutdown, or electrical system misfires.
• Maintain your batteries: Proper maintenance can extend the life of your new batteries. Regularly inspect and clean your batteries, ensuring they are securely mounted and free from corrosion. Keep an eye on fluid levels and specific gravity, and recharge or replace batteries as needed.

Remember, getting new batteries for your diesel truck is an important investment in its performance and longevity. By choosing the right batteries and maintaining them well, you can ensure your truck remains reliable and starts efficiently, even in challenging conditions.

Bleed the fuel lines and injectors

Bleeding the fuel lines and injectors is a crucial step in purging air from the diesel fuel system. Here is a detailed guide on how to perform this task effectively:

Locate the Fuel Filter Housing: Start by finding the fuel filter housing, which is usually located on the side of the engine or on top of the fuel filter. This is where you will perform the bleeding process.

Open the Bleeder Screw: Look for the bleeder screw on the fuel filter housing and open it. This will allow you to release any trapped air and fuel from the system.

Crank the Engine: With the bleeder screw open, attempt to crank the engine for a few seconds. This will create pressure in the fuel system and help push out any air bubbles.

Check for Air Bubbles: After cranking the engine, pay attention to the fuel that comes out of the bleeder screw. If you still see air bubbles in the fuel, it indicates that there is remaining air in the system.

Prime the Fuel Pump: Close the bleeder screw and continue pumping the fuel pump until it becomes hard. This step ensures that you have built up sufficient fuel pressure in the system.

Repeat the Process: Reopen the bleeder screw and crank the engine again for a few seconds. Keep repeating this process of cranking the engine, checking for air bubbles, and pumping the fuel pump until you see only fuel coming out of the bleeder screw with no air bubbles.

Close the Bleeder Screw: Once you are satisfied that all air has been purged from the system, tightly close the bleeder screw. This ensures that the fuel system is sealed and ready for operation.

Start the Engine: Finally, attempt to start the engine. It may take a few tries, and the engine may run a little rough at first. If necessary, adjust the throttle to achieve a smoother operation.

It is important to note that the process of bleeding the fuel lines and injectors may vary slightly depending on the specific make and model of your diesel engine. Always refer to your vehicle's owner's manual or seek advice from a qualified diesel mechanic if you are unsure about any steps.

Prime the fuel system

To prime the fuel system of a diesel engine, you must first fill the engine with diesel and remove any contaminants in the fuel. This process is necessary to ensure the system is properly filled and there is no remaining air inside, which would otherwise interfere with fuel delivery and engine operation.

Priming is especially important after replacing the fuel filter, as air pockets will have formed as a result of emptying the fuel. It is also required when the engine runs out of fuel, as air will enter the fuel system when the tank is empty.

To prime the fuel system, follow these steps:

• Disconnect the battery: Turn off the positive terminal first, then the negative. Move the battery away from the vehicle, ensuring it cannot come into contact with any metals.
• Locate the primer: This will be a pump or a bulb. Refer to your engine's manual for its location, which is typically near the fuel filter, on the fuel injector pump, along the fuel lines, or on the fuel filter cap.
• Check the fuel tank: Ensure there is a reasonable amount of fuel in the system.
• Locate the bleed screw: This is a small valve found in various locations in the fuel system, including near the fuel filter, close to the injector pump, or at the high points of the fuel lines. It usually has a hexagonal head with a small hole that allows the insertion of a tool for opening and closing.
• Prepare a container and rag: When opening the bleed screw, there may be some fuel release, so have a container and rag ready to catch any spills.
• Open the bleed screw: Depending on its head design, you will need either a wrench or a screwdriver to open it.
• Prime the system: Using a hand pump or priming bulb, work against the pressure to pump the fuel through the system until all trapped air escapes. With a priming bulb, press the bulb to draw fuel through the system, allowing the bulb to expand before pressing it again.
• Close the bleed screw: Once the flow becomes steady and consistent without any bubbles, close the bleed screw.
• Reconnect the battery: First, connect the negative terminal, then the positive.
• Start the engine: Turn on the ignition and allow the fuel to get pressurized. The engine may take a few seconds to start, and you may need to crank it for up to 30 seconds. If it still doesn't start, turn the key to the off position and repeat the process of heating the glow plugs.

Note: Always use a manufacturer-approved priming device for your specific engine to avoid any potential damage to the fuel system.

Seek professional help

If you are unable to diagnose the problem with your diesel engine, it may be time to seek professional help. A qualified diesel engine technician can diagnose the problem and provide you with the necessary repairs to get your engine running smoothly again.

Qualified technicians can diagnose the problem and provide you with the necessary repairs. They will have the necessary tools and expertise to safely get your engine running. They will be able to identify if there is a more serious underlying issue and resolve the problem.

If you are experiencing hard starting with your diesel engine, don't hesitate to contact a professional diesel engine repair service. They will be able to help you troubleshoot and identify the issue.

Regular maintenance and preventative measures can go a long way in preventing hard starting. However, if you are experiencing problems, it is recommended to seek professional assistance.

Frequently asked questions