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Difficult warm start from the diesel engine


  1. Difficult warm starting of the diesel engine with a slight cold start can be caused by high-pressure pump defects associated with wear of the injection pump element. When fuel is heated, its viscosity decreases and hydraulic losses in the gaps increase. In this case, the injection pump element cannot reach the pressure sufficient to open the nozzles at the starting speed, and the fuel does not get into the combustion chamber.
  2. In modern diesel engines, the warm start may be missing due to defects in the steering nozzle sensor. One of the engine nozzles (steering nozzle) is equipped with the temperature sensor. With a cold engine start, this temperature sensor gives a command to change the angle of fuel injection and to heat up the fuel in the filter (if the engine is equipped with such a system). If the sensor is damaged, it gives the same command when the engine is warm as when it is cold. As a result, the fuel mixture becomes oversaturated, vapor locks appear in fuel lines, and the engine starts with great difficulty.


  1. In the case of non-critical wear of the injection element of the high-pressure pump of a diesel engine, it is not necessary to change the fuel pump. It is recommended to flush the fuel system by introducing one of the following agents for cleaning diesel engine fuel systems into the fuel tank: After flushing, treat the fuel system with a XADO Gel-Revitalizant® for fuel systems to restore the injection element: To remove the high-pressure pump from inferior fuel or To protect the injector element from further wear, we recommend using Jet 100 Fuel Pump Protect Diesel every 10,000 km of mileage after treating the fuel system with XADO Gel-Revitalizant®.
  2. If the temperature sensor of the steering nozzle malfunctions, the sensor should be replaced.
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