System (Line) Control Pressure Test

1982 Volkswagen Pickup Custom, 1.7L Eng VIN BSECTION System (Line) Control Pressure Test
  1. Close valve on pressure gauge. With engine off, operate fuel pump. Pressure should rise to level specified. See Fuel Injection Pressure Testing table. 
  2. If pressure is too low, check fuel pump output. Disconnect fuel return line from fuel distributor and run a hose from fuel distributor to container. Operate fuel pump and measure output after 30 seconds. See Fuel Pump Output table.  If not as specified, check fuel lines, filter, fuel accumulator and fuel pump.
    FUEL PUMP OUTPUT SPECIFICATIONS

    Application 30 Sec. Flow Rate Oz. (cc)
    VW Quantum 23 (700)
    BMW, Peugeot, Porsche 928 & 928 Turbo 24 (750)
    Audi, Saab, 30(900)
    Mercedes-Benz, Porsche 911 SC, VW (except Quantum) 32(1000)
    Volvo
      Turbo 35 (1050)
      Other Models 27 (800)
  3. If pressure is too high, check for kinked or blocked fuel return line. If lines are clear, system pressure regulator must be adjusted. Turn pump off, loosen return line fitting, and relieve pressure.
  4. Loosen line pressure regulator nut. Remove shims, spring(s) and plunger. Raise system pressure by adding shims; lower pressure by removing shims. Be sure "O" rings are in good condition. If piston is scored or damaged, fuel distributor must be replaced. See Fig 1.
    Fig 1: Pressure Regulator in Fuel Distributor
    G09315282Courtesy of AUDI OF AMERICA, LLC

    Replace fuel distributor if piston is scored or damaged. 

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.