The 1989 Chevrolet Corvette comes with a 5.7-liter (350 cubic-inch) engine. This particular year uses a throttle body -- it looks like a carburetor, but has fuel injectors in it. You will need a special tool to do this job. Without the special tool, you could damage the throttle valve. When replacing the bad injector, replace the O-rings and grommets on the other injectors while you are in there. Spending a few extra dollars could save you time and money later on.
Correction, the 1989 Chevrolet Corvette has a TPI or Tuned port injection system utilizing one injector per cylinder. The 1984 Chevrolet Corvette is the only C4 corvette to use the Cross-Fire injection system utilizing two throttle bodies.
Tools Used: Set of wrenches, Set of sockets, Tape, Marker, Rags, Special tool J-9789-118 or BT-30-15, Screwdriver, Thread locker, Torque wrench
Replace the Fuel Injectors
Disconnect the negative battery cable and lay it aside, ensuring that it does not touch metal. Remove the air cleaner assembly, using the appropriate sockets. Unplug the injector, idle air control valve and throttle position sensor wiring harness connectors. Unclip the wiring harness from the throttle body.
Mark the vacuum lines on the throttle body assembly, using the tape and marker, then disconnect the lines from the throttle body. Unclip the throttle cable, transmission detent cable and the cruise control cable from the throttle body.
Remove the fuel tube between the two throttle body units. Hold one nut with one wrench to keep it from turning while you turn the other nut with a wrench. Remove the five screws and lock washers on the fuel meter cover, using the appropriate socket. Lift off the fuel meter cover, with the fuel pressure regulator, from the rear unit. Lift off the fuel meter cover and the accumulator from the front unit. Pay attention to how they are positioned on the throttle body -- mark them if you have to, as they must go on exactly as they came off.
Remove the fuel outlet passage and discard it. Do not remove the fuel meter cover gasket, and do not remove the four screws that secure the fuel pressure regulator or accumulator on the cover. Both the regulator and accumulator are spring-loaded and are under heavy compression. Remove the foam pressure regulator-sealing ring from the rear throttle body.
Remove the throttle bodies, using the appropriate sockets, and set them in the special holding tool. Lift the injector by gently prying it out of the throttle body, using the screwdriver. If you are removing both injectors, mark them as front and rear, as they are different and not interchangeable.
Rotate the injector fuel filter back and forth to remove it from the base of the injector. Remove and discard the fuel meter cover gasket. Remove the O-ring and steel back-up washer in the top counterbore of the injector cavity. Remove the small O-ring at the bottom of the injector cavity.
Install a new fuel filter on the nozzle of the injector. Lubricate the new O-rings with transmission fluid, then push them onto the injectors (nozzle ends). Push the ring up against the injector fuel filter.
Install the back-up washer in the top of the counterbore of the injector cavity. Lubricate the new large O-ring with transmission fluid. Install the O-ring above the back-up washer and press it down into the cavity counterbore. The O-ring should be flush with the top of the fuel meter body casting surface.
Reinstall the injector into the cavity, aligning it with the raised lug on the injector base, with the cast-in notch in the fuel meter body. Push down on the injector, making sure it is fully seated in the cavity. Reinstall the a new dust seal for the pressure regulator, then install the fuel meter cover and fuel meter outlet gaskets.
Place the fuel meter cover with the fuel pressure regulator on the rear throttle body assembly. Place the fuel meter cover with the accumulator on the front unit. Coat the threads of the fuel meter cover attaching screws with thread locker, then install the screws and lock washers. Tighten the screws to 28 inch-pounds of torque. Make sure the two short screws are next to the injectors.
Reinstall the connecting fuel tube between the front and rear throttle body units and tighten then connections to 24 foot-pounds of torque. Reattach the fuel inlet and return lines. You will need two wrenches for both connections -- one to hold the inside nut and the other to turn the outside nut.
Reconnect the throttle cable, transmission cable and cruise control cable. Reattach the vacuum lines. Plug in the electrical connectors for the injectors, idle air control valve and the throttle position sensor. Clip the wiring harness back onto the throttle body. Reinstall the air cleaner assembly and reconnect the battery.
Tips & Warnings
Place rags under the fuel line connections, to keep the fuel from pooling on the intake.
Do not immerse the fuel meter covers and their respective parts in cleaner. The cleaner and moisture will damage the diaphragms and gaskets.
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