I recently added more clear lines. Additionally, the secondary fuel filter was also overhauled with new O-rings as per previous suggestions. Serviced the bypass valve, stretched spring to 27mm. New crush rings for reinstall.

Source of air infiltration found in the fuel system. See video:

https://youtu.be/FH6y6KFP9JM

After revving the engine, air is emitted from the bypass valve of the injector pump back into the fuel filter housing and out the expansion hose. There is no doubt that air is coming out somewhere from the injector pump. From the fuel lines or primary fuel filter, I don't see air. The return lines from injectors appears to have very little flow like before. What is the reason behind this?

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Theseus

Instragram: doss_project
1984 300SD - 930 Blue, OM 617
Murfreesboro, TN

Theseus owned a ship in Greek mythology, and when a part of the ship needed replacing, it was replaced. Eventually, everything was replaced. Is it the same ship? (I own the car of Theseus. )