Fuel Pump Pressure
- Before disconnecting, cover fuel line connector using shop towel to absorb any fuel spray. Connect Fuel Pressure Gauge (5011 ) between fuel line and fuel rail. Seal free end of hose using Plug (5266 ). Start fuel pumps. On 240, remove panel under right side of instrument panel and remove system relay. See Figure . On 740 and 940, lift out central electrical unit and remove system relay. See Figure .
- On 240, 740 and 940, connect a jumper wire between relay terminals No. 30 and 87/2. See Figure . On 960, remove fuses No. 30 and 31. See Figure . Connect jumper wire between fuse terminalsNo. 30 and 31. On all models, fuel pumps should start. Fuel filler cover can be removed to determine whether main pump is operating.
- Fuel pressure should be 42 psi (3 kg/cm2 ). If pressure is too low, pinch return hose by hand and check whether pressure rises. DO NOT allow pressure to exceed 86 psi (6 kg/cm2 ).
- If pressure rises rapidly, pump and lines are okay. Replace pressure regulator and recheck line pressure. If pressure rises slowly, fuel filter, fuel pump strainer or fuel lines are blocked. If pressure does not rise, fuel pump is probably faulty.
- If pressure is too high, remove jumper wire between relay or fuse terminals. Remove return hose from pressure regulator, and blow in pipe. Remove vacuum hose from pressure regulator, and blow in pipe. If both hoses are open, pressure regulator is defective. Replace regulator, and recheck pressure.