How to Replace a 1991 Toyota 3.0 Fuel Injector

The 1991 Toyota 4-Runner with the 3.0 engine uses one of two different types of fuel injection: multiport or sequential. The multiport system features one injector for each cylinder, plus a cold-start injector. The cold-start injector provides additional fuel, which is needed at start-up. Each injector sprays fuel into its intake port. The electronic fuel injection (EFI) computer controls the injectors.

Difficulty:

Challenging

Instructions

things you'll need:

• Needle-nose pliers
• Set of wrenches
• Clean drain pan
• Set of sockets
• Screwdriver

1. • 1

     Lift the cover off the relay box, which is located near the driver's-side fender well. The underside of the cover contains a diagram of the relays in the box. Locate the fuel pump relay and pull it out with the needle-nose pliers. Disconnect the battery ground cable and lay it aside.

   • 2

     Locate the engine identification sticker on the underside of the hood. If your engine is a 3VZ or a 22R-E, place the drain pan under the radiator petcock. Loosen the petcock and allow the antifreeze mixture to drain into the drain pan.

   • 3

     Disconnect the accelerator and throttle cables from the throttle body area on all engines. Remove the air intake chamber using the appropriate socket. If the engine is a 22R-E, remove the throttle body using the appropriate sockets. If the engine is a 3F-E, label all vacuum hoses and wires that are attached to the throttle body, then, remove them by loosening clamps or unplugging the wires.

   • 4

     Unplug the main wiring harness connectors for the sensors on the intake and around the fuel rail if your engine is a 3VZ-E or 3F-E model. Move the main wiring harness out of the way. If you think you might get confused when plugging things back in, label the plugs before removing them.

   • 5

     Unplug the wiring connector plugs from the tops of the fuel injectors by pushing the plastic tabs in and pulling the connectors off the injectors. Unclamp the two plastic clamps holding the wiring harness to the fuel delivery pipe.

   • 6

     Disconnect the fuel line to the fuel delivery rail on 22R-E and 3F-E engines. Unbolt and remove the fuel rail, leaving the injectors attached, from the engine. Take care that the injectors do not fall out. If you have a 3VZ-E engine, disconnect the vacuum hose from the bimetal vacuum switching valve (BVSV). Unbolt the four union bolts and the number 2 and number 3 fuel pipes. Pull the injectors from the fuel delivery pipes.

   • 7

     Insert the new insulators into the intake manifold injector holes. Slide a new grommet and O-ring onto the delivery pipe of each injector.

   • 8

     Coat each O-ring with a bit of gasoline, then press each injector into the delivery pipe, ensuring that the injectors are not crooked. Carefully hold the injector pipe over the intake and lower it onto the manifold, ensuring that each injector goes straight into its injector hole. Tighten the rail mounting bolts to 12 foot-pounds of torque. Turn each injector in its mount--the injectors should turn freely. If not, remove the injector and check the O-ring.

   • 9

     Clip the wiring harness back into the delivery pipe. Plug the injector wiring connectors in. Reinstall the throttle body if it was removed. Reinstall all wiring harness connections and the vacuum lines. Reattach the throttle and accelerator cables. Close the petcock on the radiator, if you drained it. Refill the radiator. Plug the fuel pump relay in. Reconnect the battery ground cable. Start the engine and check for fuel leaks.