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Why is a fuel injected engine hard to start when hot?

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2 Answers

  1. John D Collins on Nov 26, 2014

    It depends on the engine, but this is most often caused by vapor in the fuel lines, including the lines from the fuel distributor to the injectors. In a TCM large bore engine such as the IO520, the vapor is also in the fuel lines between the fuel pump and the throttle body. A heat soaked engine driven fuel pump will not do a good job of purging the vapor. In my Bonanza, the technique employed is to run the boost pump for a minute or so with the mixture at idle cutoff and then prime for the start. This recirculates cold fuel thru the lines and engine driven pump and permits a normal start after running the boost pump. This technique works on my engine, but is not suitable for all systems. Follow your POH for guidance on hot starts.

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  2. psequeira on Nov 26, 2014

    Thank you John

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