REMOVAL & INSTALLATION
See Figures 1 through 19
- Disconnect the negative battery cable.
- Remove the air intake tube with resonator and fresh air tube.
- Properly relieve fuel system pressure.
Remove the fuel line bracket bolt, then disconnect the fuel supply and return lines in the following manner:
- On 1991-94 models, be sure to use a 15 / 16 in. (24mm) backup wrench to prevent inlet port or bracket damage. If necessary, remove the fuel line bolts and rotate the rail slightly for wrench access. Remove and discard the old O-rings from the fuel lines using a suitable seal removal tool or brass pick.
- On 1995-98 models, disengage the fuel line(s) from the rail and pressure regulator by compressing the two plastic retaining tabs of the quick-connect fitting and pulling on the line. Remove and discard the plastic retainer.
- Disconnect the vacuum hose from the fuel pressure regulator on 1991-97 models.
- Detach the PCV hose from the camshaft cover.
- Remove the throttle cable bracket bolts, then disconnect the cable from the throttle lever. Lay the cable over the intake manifold and out of the way.
- Unplug the fuel injector electrical connectors and, if not done already, remove the fuel rail bolts.
- Remove the fuel rail assembly by carefully pulling the rail back and upward to pull the injectors from the manifold ports. Be careful not to damage the injector spray tips and the electrical connectors. Rotate the rail so the injectors point downward, then lift the rail end opposite the fuel connections to remove the rail from between the camshaft cover and intake manifold.
- Make sure the rails and connectors are clean and free of dirt. Remove and discard the lower injector O-rings seals.
- If injector removal is required, slide the injector retaining clip off the injector and pull the injector from the rail assembly. Remove and discard the upper injector O-rings seals.
- If removed, lubricate and install the new injector O-rings with clean engine oil and install with the injector assembly into the fuel rail. Install the injector retaining clip.
There are 3 types of injector retaining clips. The 1st design, which was used on some engines built prior to January 1st, 1991, may cause injector ticking noise. If injectors are removed from the fuel rail assembly and this type is found, they must be replaced with the 2nd clip design. Do not attempt to substitute the 3rd design of clip; only 1995 and later models can use the 3rd design.
- Lubricate the new lower injector O-rings with clean engine oil, then install.
- For 1991-94 models, lubricate the new fuel inlet and return O-rings, then install the O-rings into the fuel outlet of the pressure regulator and inlet of the fuel rail.
- Starting with the proper end (on 1991-97 models, the end containing the pressure regulator), and with the injectors pointing downward, guide the fuel rail assembly through the passage between the camshaft cover and the intake manifold, from the power steering pump side of the engine. Align the injectors with their respective ports, then rotate the fuel rail and carefully push the injectors into their ports.
- Verify that the injectors are properly seated in the intake manifold.
- Install the fuel rail retaining bolts and tighten to 22 ft. lbs. (30 Nm) on 1991-94 models or 89 inch lbs. (10 Nm) on 1995-98 models.
- Connect the fuel injector wiring harnesses.
- Connect the PCV valve hose to the camshaft cover, and the vacuum line to the pressure regulator, making sure they are properly seated.
- Install the throttle cable bracket bolts and tighten to 19-22 ft. lbs. (25-30 Nm), then connect the throttle cable.
Lubricate the male ends of the fuel supply and return lines with clean engine oil. Connect the fuel supply and return lines in the following manner:
- On 1991-94 models, be sure to use a 15 / 16 in. (24mm) backup wrench to prevent inlet port and bracket damage. Tighten the fittings to 133 inch lbs. (15 Nm).
- On 1995-98 models, install new quick-connect fitting retainers into the female cavity of the connection, then attach the fitting(s), and pull back on it (them) to confirm the connection.
- Install the fuel line bracket bolt and tighten to 106 inch lbs. (12 Nm).
- Connect the negative battery cable, then prime the fuel system by cycling the ignition switch ON and OFF .
- Start the engine and check for leaks.
- Shut the engine, then install the air intake tube and resonator assembly.
See Figures 20 and 21
- Unplug the injector connector and use an ohmmeter to check the resistance of the injector coil. It should be 11.5-12.5 ohms.
A single MFI injector may short internally, causing a no-start condition, yet not blow the fuse or damage the PCM. If a multimeter is not available to test the injectors, unfasten the injector electrical connectors, one at a time, and attempt to start the engine. If the engine starts with one injector disconnected, the faulty injector has been found.
Make sure all injector harnesses are unplugged, then attach a Noid light (tool SA9194E or equivalent) to the injector connector terminal so that the light can be seen from the driver' seat. Operate the starter and observe the Noid light.
- If the Noid does not illuminate at all, check for power to the injector(s). The injectors receive power through the pink or pink/black wire from the 10 amp INJ fuse in the underhood junction box, any time the ignition switch is ON . The PCM operates the injectors by completing the ground circuit through the dark green or dark blue wires.
- If the test light stays on steadily, check for a short to ground of the wire between the injector connector and the PCM.
A pulsing Noid light does not necessarily indicate enough voltage to properly operate the fuel injector. If it is still questionable whether or not an injector is pulsing, connect a known good injector to the circuit and tightly grip the injector while an assistant cranks the engine. If injector pulses are felt, the circuit is good.
See Figure 22
- Connect the test gauge and run the fuel pump and system pressure tests as described in the Fuel Pump tests.
For 1991-97 models, perform the following:
- Disconnect the return line from the fuel rail. Cap the opening at the fuel rail with plug SA9410E or equivalent.
- Disconnect the fuel pressure regulator vacuum line.
- Disconnect the fuel line bracket retaining bolt, but leave the supply line attached to the rail assembly and connectors.
- Remove the bolts holding the fuel rail, then pull the rail and injectors straight out so the injector tips are visible while still in their ports. It may be necessary to rotate the throttle. Use wire to hold the assembly back against the intake manifold.
- Wipe the injector tips free of fuel or debris and place a clean cloth under them, just contacting the injector tips to spot leaking fuel.
- Cycle the ignition ON and OFF , without starting the engine, to build system pressure to a minimum of 46 psi (317 kPa) on the gauge for 1991-97 models or 40 psi (276 kPa) for 1998 models.
- Allow the pressure to hold for five minutes, then check the cloth for fuel leakage. If a portion of the towel becomes wet with fuel, the faulty injector(s) must be replaced.
- Bleed off the system pressure, cycle the ignition to rebuild fuel pressure, then allow the system to sit for five minutes. Check the cloth again for signs of leakage and, if any is found, replace the faulty injector(s).
- Release fuel system pressure again, then remove the gauge and recap the test port.
Remember to lubricate the injector O-rings with clean engine oil upon installation of the fuel rail/injector assembly.
- Install the fuel rail/injector assembly.
- Attach the fuel line bracket retaining bolt.
For 1991-97 models, perform the following:
- Attach the fuel pressure regulator vacuum line.
- Remove the cap from the fuel rail opening and connect the return line to the fuel rail.
- Start the engine and check the system for leaks.