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 one 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 end 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.

Fig 1: Logic Module Pin Identification - Connector 1

Chapter Navigation

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Fuel System Pressure Test