You may have improperly installed one or two of the fuel valves. A fuel relief valve should be installed on the injection pump's fuel return circuit. This is located on the pump side close to the engine block, and near the front.

Next, an air bleed valve (with an orifice) should also be installed on your fuel filter's return fuel circuit.

Have you checked your in-tank strainer and fuel pre-filter (nearest the feed pump) for blockage?

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Jake