780 V6-2849cc 2.8L SOHC B280F (1987)
Fuel System Pressure To Low
b. Pressure to low:
Pinch fuel return line with hand and check pressure increase.
CAUTION:Do not allow the pressure to exceed 600 kPa (87 psi).
If pressure rises quickly, pumps and fuel lines are O.K.. Replace fuel regulator and retest.
If fuel pressure rises slowly, this indicates a blocked fuel filter, tank pump or supply line. Check the individual components and replace as
needed.
If pressure does not rise, main fuel pump is defective. Replace and retest with new pump.
Checking Pressure Regulator
11.
Check the fuel pressure regulator by disconnecting the vacuum hose and connecting a vacuum pump to the pressure regulator.
12.
While monitoring the pressure gauge, apply vacuum to the pressure regulator. Check that the fuel system pressure drops as vacuum increases.
Diaphragm must be able to retain the vacuum applied, no bleed-off should occur.
If pressure regulator does not perform correctly, replace and retest with new pressure regulator.
13.
Disconnect the vacuum pump.
14.
Disconnect fuel pump relay lead.
15.
Disconnect all test equipment and reconnect all hoses and relays. Use new washers on the fuel line connectors.
WARNING: Fuel lines are under pressure. When disconnecting fuel lines, cover the connection with a shop towel to protect yourself from the
excess pressurized fuel.
16.
Run engine and recheck fuel line connections for leakage.
