Maybe

3rd lesson learned: Install a vacuum gauge to tell you when to change filters. If you install it at the common of the 3 way valve, it will tell condition of both the diesel and VO filters. I am going to say that you wasted time and money by changing the diesel filter since you probably have less than 3k diesel running miles through your diesel filter in 40K of VO miles.

Don't run out of fuel!

Having an external lift pump (to the IP) can pump a lot of air into the IP very quickly when you run out of fuel or have air leaks in fuel lines. If you are not prepared and have all the tools to purge air, you are stranded.

Didn't your Frybrid manual have instructions on how to purge air out the modified fuel system for Mercedes?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked