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 ) or use Fuel Drainage Unit (981 2270 , 2273 and 2282 ). Start fuel pumps. On 850, lift cover on central electrical unit located in engine compartment and remove fuel pump relay. See Figure .
- Connect a jumper wire between relay terminals No. 1 and 3. See Figure . Fuel pump should start. Fuel filler cover can be removed to determine whether main pump is operating.
- Fuel pressure should be about 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.