Dieseling, also known as engine run-on, is a common issue that affects Chevy 350 engines. This problem occurs when the engine continues to run or sputter after the ignition is turned off. Let's explore the causes and solutions for this frustrating issue.

Causes of Dieseling

Several factors can contribute to dieseling in a Chevy 350 engine:

1. Carbon buildup: Excessive carbon deposits in the combustion chambers can act as hot spots, igniting fuel after the engine is shut off.

2. Low octane fuel: Using fuel with inadequate octane rating can increase the likelihood of dieseling, especially in high-compression engines.

3. High idle speed: If the engine's idle is set too high, it may continue to draw fuel and air even after the ignition is turned off.

4. Timing issues: Improper ignition timing can lead to hot spots in the combustion chamber, causing dieseling.

5. Faulty carburetor: A poorly adjusted or malfunctioning carburetor can allow excess fuel to enter the engine, contributing to run-on.

Solutions to Prevent Dieseling

To address dieseling in your Chevy 350, consider the following solutions:

Adjust Timing and Idle Speed

Ensure your engine's timing is set correctly. For most Chevy 350 engines, the initial timing should be in the low to mid-teens. Adjust the idle speed to the lowest comfortable setting that maintains a reliable idle.

Use Higher Octane Fuel

Switch to a higher octane fuel, which is less volatile and less likely to cause dieseling. This is especially important for high-compression engines.

Clean Carbon Deposits

Remove carbon buildup from the combustion chambers. You can use fuel additives like Sea Foam or Techron to help clean deposits over time. For severe cases, consider a professional carbon cleaning service.

Install an Anti-Dieseling Solenoid

Consider installing an anti-dieseling solenoid, which closes the throttle plates completely when the ignition is turned off. This prevents fuel and air from entering the engine after shutdown.

Check and Adjust the Carburetor

Ensure your carburetor is properly adjusted. Pay attention to the idle mixture screws and accelerator pump. If problems persist, consider having the carburetor professionally rebuilt or replaced.

Upgrade Ignition Components

Install new spark plugs and check the condition of your ignition wires. Consider upgrading to a high-performance ignition system for better combustion control.

Preventing Future Dieseling

To minimize the risk of dieseling in the future:

  • Regularly maintain your engine, including timely oil changes and tune-ups
  • Use high-quality fuel and consider occasional use of fuel system cleaners
  • Avoid prolonged idling, which can contribute to carbon buildup
  • Address any performance issues promptly to prevent more serious problems

By following these guidelines and implementing the appropriate solutions, you can effectively combat dieseling in your Chevy 350 engine and enjoy smoother, more reliable performance.

FAQs About Chevy 350 Dieseling

    • Can dieseling damage my engine?
      While occasional dieseling isn't typically harmful, persistent dieseling can lead to increased wear on engine components and should be addressed promptly.
    • How long does it take for carbon cleaning additives to work?
      It may take 2-3 full tanks of treated fuel before you notice a significant improvement in dieseling symptoms.
    • Is dieseling more common in older Chevy 350 engines?
      Yes, older engines are more prone to dieseling due to carbon buildup and wear on components over time.