6.6 Duramax Difficult Hot Start

Several things could be causing a hot start issue in your 6.6L Duramax. Two of the most likely causes are:

A Fuel System Leak

A fuel leak at the injectors, pump, lines or other connections can cause air to enter the fuel system, leading to fuel delivery issues that affect starting. Inadequate pressure or imbalances in the fuel mixture at the injectors may be exacerbated when the engine is warm. You may notice the slight smell of fuel around the engine.

Poor Fuel Quality

Low-quality or contaminated fuel can cause starting issues by disrupting proper combustion. Contaminants such as dirt, water or bacteria can restrict fuel flow through the fuel filter, resulting in difficulty starting after the engine has been running, rough idling or stalling.

Inconsistencies or faults in the fuel line can significantly affect hot starting performance. Here’s what to check for when diagnosing hot start issues on your 6.6L Duramax engine: 

1. Check for fuel system leaks: Inspect fuel lines, injectors and connections for visible damage. Pressure-test the fuel system to ensure there are no leaks and check for loose connections before tightening or replacing any damaged parts.
2. Treat the fuel system with Diesel Extreme: Add Hot Shot’s Secret Diesel Extreme to your fuel tank to clean the injectors and improve fuel quality. Run this treatment through your vehicle’s system to remove any carbon buildup and improve combustion with the cetane booster in the additive.
3. Replace fuel filters: Examine and clean any clogged or dirty filters to ensure smooth fuel flow. If a filter is damaged, swap it out with a new one.
4. Inspect and test the fuel pump: Check the fuel pump for proper operation. A failing pump can cause a lack of fuel pressure, making hot starts difficult.

Give your 6.6L Duramax everything it needs to stay in good running order, whether it’s the first time or the fifth time you crank the engine. Ensure reliable engine performance by understanding potential problems and proactively protecting your engine. You can do this by:

• Regularly inspecting the fuel system: Perform periodic checks of the fuel lines, filters and injectors to catch any leaks or damage early.
• Maintaining fuel quality: Use high-quality fuel and add Everyday Diesel Treatment (EDT) to keep the fuel system clean and prevent deposits and other common diesel issues.
• Change fuel filters regularly: Replace fuel filters at recommended intervals to ensure smooth fuel flow and prevent problems caused by clogged filters.