Fuel Pressure (2.6L)
- Release fuel pressure. See FUEL SYSTEM PRESSURE RELEASE under FUEL SYSTEM.
- Install a fuel pressure gauge between fuel pressure regulator and fuel distributor pipe. Bleed air from fuel line going to pressure gauge. See Fig 1
.
Courtesy of ISUZU MOTOR CO.
- Unplug fuel pressure regulator Vacuum Switching Valve (VSV) connector on right side fender skirt. This is a 4-wire connector with Black and Blue wires in harness. ECM controls VSV to cut vacuum to fuel pressure regulator during hot engine starts.
- Start engine. Measure fuel pressure at idle. Disconnect fuel pressure regulator vacuum hose. Note fuel pressure at idle with vacuum hose disconnected (no vacuum). Fuel pressure should be 42 psi. (3.0 kg/cm2
).
- If fuel pump pressure is low, check for fuel leaks, restrictions in intake side of fuel pump, leaking injectors, faulty pressure regulator or faulty fuel pump. If fuel pressure is too high, check for restrictions in return line to tank or faulty pressure regulator. If fuel pressure did not change when pressure regulator was disconnected, replace pressure regulator.
- Reconnect pressure regulator vacuum hose and check fuel pressure (with vacuum). Fuel pressure should be 35 psi. (2.5 kg/cm2
). Apply battery voltage to VSV connector Blue wire terminal and ground to Black wire terminal (with vacuum). Fuel pressure gauge should read approximately 42 psi (3.0 kg/cm2
). If fuel pressure is not within specification, check for defective VSV. See Fig 2
.
- Disconnect and plug vacuum hose from fuel pressure regulator. Stop engine. Ensure fuel pressure remains more than 35 psi (2.5 kg/cm2
) for 4 minutes after engine stops. This is rest fuel pressure.
- If pressure drops, check for leaking injectors, faulty pressure regulator or bad check valve in fuel pump. If engine does not start, by-pass fuel pump relay to check for fuel pressure.
- Remove fuel pump relay from underhood fuse/relay box. Connect a jumper wire between terminals No. 1 and 3 of fuel pump relay connector in fuse block. See Fig 3
and Figure
.
- If fuel pump does not operate, check for battery voltage to terminal No. 3. If battery voltage is present, check for open in fuel pump circuit. If fuel pump operates with jumper wire installed, check fuel pump relay and relay energizing circuit. Repair as required.
Courtesy of ISUZU MOTOR CO.
Courtesy of ISUZU MOTOR CO.