1993 Lexus LS 400FACTORY OEM SERVICE PROCEDURE

Fuel Injectors

  1. Start engine. Using a stethoscope, ensure each injector is making a "clicking" noise during operation. If "clicking" noise is not heard, ensure wiring connector is securely fastened.
  2. Ensure an injector signal is present on injector harness connector. Turn engine off. Disconnect injector electrical connector. Using a DVOM, measure resistance across injector terminals.
  3. Resistance should be approximately 13.8 ohms. If resistance is not as specified, replace fuel injector. Disconnect negative battery cable. Remove injector from engine.
  4. Place injector into a container to catch fuel spray. Turn ignition on. DO NOT start engine. Using a jumper wire, connect terminals FP and +B of check connector. See Fig 1.
    Fig 1: Check Connector Terminal ID (ES300 Shown; Others Similar)
    G90D18864Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  5. Connect battery voltage to injector terminals for 15 seconds. Ensure an even, cone-shaped fuel spray is observed from injector. If fuel spray is not satisfactory, replace injector. If fuel spray is satisfactory, check volume of fuel delivered by fuel injector.
  6. On GS300, fuel volume should be 2.4-3.0 ozs. (70-78 cc) for 15 seconds of operation. On ES300, fuel volume should be 1.8-2.16 ozs. (54-64 cc) for 15 seconds of operation. On LS400 and SC400, fuel volume should be 1.9-2.4 ozs. (55-70 cc) for 15 seconds of operation. On SC300, fuel volume should be 2.4-3.0 ozs. (70-88 cc) for 15 seconds of operation. Check each injector 2-3 times for volume. Maximum volume difference between injectors is .16 ozs. (5 cc) for GS300 and ES300, .17 ozs. (10 cc) for SC400 and LS400, and .27 ozs. (9 cc) for SC300. If volume is not satisfactory, replace injector.
  7. Remove battery voltage from injector. With injector still placed in container, observe injector tip. If injector drips more than one drop of fuel within one minute, replace fuel injector.
Factory Service Tools

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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.

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