System (Line) Pressure Test

1. Turn pressure gauge knob or lever to CLOSED position. Turn ignition ON. Pressure should be 64-72.5 psi (4.5-5.1 kg/cm² ). If pressure is too high, check for blocked fuel return line or defective line pressure regulator in fuel distributor.
2. If pressure is too low, check for low fuel pump pressure. Also check for a clogged fuel tank strainer, leaks in fuel line, or defective line pressure regulator in fuel distributor.
3. System (line) pressure can be adjusted by adding or removing shims from line pressure regulator in fuel distributor. Pressure can be increased by adding shims, decreased by removing them.
4. Shims are available in 0.004" (0.10 mm) thickness to provide pressure change of 0.85 psi (0.06 kg/cm² ) or 0.020" (0.5 mm) to provide pressure change of 4.3 psi (0.3 kg/cm² ). Thicker shims should be used first, thinner shims should be used when line pressure is more than 70 psi (4.9 kg/cm² ).

Fig 1: Cold Engine Control Pressure Test (Pressure/Temperature Relationship) Graphs

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