Fuel System Pressure Test
- Prior to working on fuel system, fuel pressure must be relieved in the following manner. Loosen gas cap to release any in-tank pressure. Remove wiring harness connector from any injector. Ground 1 terminal of that injector with a jumper wire.
- Connect a jumper wire to other terminal of injector and touch positive terminal of battery for NO MORE than 10 seconds. Remove jumper wires and service fuel system.
- To test fuel system pressure, remove fuel supply hose from throttle body. Connect pressure gauges (C-3292 and C-4749) between fuel filter hose and throttle body. Start engine.
- If gauge reads 51-55 psi (3.6-3.9 kg/cm2 ), pressure is correct and no further testing is required. Reinstall fuel hose using a new clamp.
- If fuel pressure is too low, install pressure gauge between fuel filter hose and fuel line. Start engine. If pressure is now correct, replace fuel filter.
- If no change is observed, gently squeeze return hose. If pressure increases, replace pressure regulator. If no change is observed, problem is either a plugged pump filter sock or defective fuel pump.
- If fuel pressure is too high, remove fuel return hose from pressure regulator end. Connect another piece of hose and place other and of hose in clean container.
- Start engine. If pressure is now correct, check for restricted fuel return line. If no change is observed, replace fuel regulator.