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To determine if an improper grade of fuel oil is causing excessive black or gray smoke, perform the following: ‪

  1. Acquire a fuel oil sample from the vehicle fuel tank(s).
  2. Submit fuel oil sample for an ASTM test analysis.
    1. If the fuel oil meets specifications, check for a restrictive air cleaner; refer to section .
    2. If the fuel oil did not meet specifications, resolve improper grade of fuel; refer to section .

Improper Grade of Fuel Resolution

Perform the following steps to resolve the improper grade of fuel oil: ‪

  1. Drain the fuel oil tanks, refer to OEM guidelines, and dispose of properly.
  2. Refill the fuel oil tanks with new fuel oil having a cetane number greater than 40.
  3. Verify fuel oil resolution; refer to section .
Test the Engine with New Fuel Oil

Perform the following steps to determine if the fuel oil refill resolved the excessive exhaust smoke condition: ‪

  1. Start and run the engine.
  2. Run the engine at idle with a no-load for approximately 5 minutes, allowing the engine coolant to reach normal operating range.
  3. Visually inspect exhaust for excessive smoke.
    1. If the engine exhaust smoke emission appears normal, no further troubleshooting is required. Shut down the engine.
    2. If the engine exhaust smoke is excessively black or gray, shut down the engine. Check the air filter; refer to section .