UK Car Repair: Low Pressure on Lucas Fuel Pump, pressure release valve, opel vectra

Question
Dear William Brady,

Thank you in advance!

I have a car which is Opel-Vectra 1.7D with Lucas type injection fuel pump, I faced its engine reducing power. When I checked the pressure of its Lucas fuel pump, I found it below the normal operating pressure, so could you please give me hint how to repair or could you please direct me to experts who can help?


Answer
How did you check the pressure and what was it? There is a pressure release valve in the fuel pressure line for the injectors This could be faulty. There is also a one way valve in the pump which is intended to prevent fuel leaking back to the tank, this can also be the problem!  You need to find away to block both paths one at a time to see where the loss is.