DF300 Hard Start

[JHK]

2019 DF300 has hard start/extended crank. Replaced low/ high pressure fuel filters, high pressure fuel pump, and fuel pressure regulator. Fuel psi is 37 running. When engine is stooped psi slowly sinks to 5 psi.

What hold psi in fuel rail? I see no leaks.

 

[William01]

Fuel pressure while engine is running 36psi, shut down engine and you should have 28psi residual pressure after 5 minutes. From a 2009 DF90A service manual. If you have 28psi after 5 minutes then your hard starting might be something else. With the work done check for kinks/tight bends in the fuel line. The list I have mentions a few sensors but they should provide a fault code

 

[JHK]

Very low residual pressure (5psi) after 5 to 10 mins. If I cycle the key a few times or crank 2- 3 times it starts and runs fine. No codes

 

[William01]

As far as I know fuel pressure and fuel can escape from a injector stuck open or the float not set to factory specifications and push fuel out the evaporation line. In both cases the fuel will get dumped into the crankcase. Check your oil level, if over full then thats where your fuel is going. Failing that then you have a fuel leak somewhere. See attached screenshot.

 

[JHK]

I appreciate the information you provided along with reference material from the service manual. I will make checks this weekend.

Thanks!

 

[William01]

Hope it helps

 

[JHK]

With inline pressure guage installed psi at 36 with key on. Psi decreased 0 psi with key off. Removed fuel rail found #3 injector dribbling with fuel. Replaced injector; starts and runs great.

Thanks for your help!

 

[William01]

Glad you got it sorted out. Hows the oil level?

 

[JHK]

It was not overfull. I changed just in case it was contaminated.