Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1994 Lexus ES 300FACTORY OEM SERVICE PROCEDURE
Fuel Pressure
- Ensure a sufficient amount of fuel is in fuel tank and battery is charged. Turn ignition off. Connect a jumper wire between terminals +B and FP of DLC No. 1. See Fig 1. Turn ignition on. In engine compartment, grasp fuel hose leading from fuel filter.
- Fuel pressure should be felt in hose and fuel return noise should be heard. Turn ignition off. If fuel pressure is evident, go to next step. If fuel pressure is not evident, check fusible links, fuses, SFI main relay, fuel pump, PCM and wiring connections.
- Disconnect negative battery cable. Wait at least 90 seconds for air bag back-up power supply to be depleted. Connect fuel pressure gauge to fuel line fitting (banjo bolt) at:
- Fuel filter outlet
- Ensure ignition is off. Reconnect negative battery cable. Connect a jumper wire between terminals +B and FP of DLC No. 1. See Fig 1. Turn ignition on, with engine off. Check fuel pressure.
- If fuel pressure is 38-44 psi (2.7-3.1 kg/cm2 ), go to next step. If fuel pressure exceeds specification, replace fuel pressure regulator. If fuel pressure is less than specification, check fuel hose and connections, fuel pump, fuel filter, fuel pressure regulator and injectors. See SYSTEM/COMPONENT TESTS article in the ENGINE PERFORMANCE section.
- Disconnect jumper wire from DLC No. 1. Start engine. Disconnect and plug vacuum hose at fuel pressure regulator. With engine idling, check fuel pressure. See FUEL PRESSURE SPECIFICATIONS table. If fuel pressure is within specification, go to next step. If fuel pressure is not within specification, check vacuum hose and fuel pressure regulator.
- Reconnect vacuum hose to fuel pressure regulator. With engine idling, check fuel pressure. See FUEL PRESSURE SPECIFICATIONS table. If fuel pressure is not within specification, check vacuum hose and fuel pressure regulator.
- If fuel pressure is within specification, turn engine off, noting fuel pressure. If fuel pressure remains greater than 21 psi (1.5 kg/cm2 ) for at least 5 minutes after engine is turned off, fuel pressure is okay. If fuel pressure decreases to less than 21 psi (1.5 kg/cm2 ) within 5 minutes, check fuel pump, fuel pressure regulator and fuel injectors. See SYSTEM/COMPONENT TESTS article in the ENGINE PERFORMANCE section.
FUEL PRESSURE SPECIFICATIONS
| Application Type | At Idle With Vacuum | At Idle Without Vacuum |
|---|---|---|
| ES300 | 33-38 (2.3-2.7) | 38-44 (2.7-3.1) |
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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