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.
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HOMESERVICE MANUALSMAZDA1991RX-7 BASE, 2D CONVERTIBLE, STANDARDREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - BASIC TESTINGFUEL SYSTEM (FUEL INJECTION)FUEL PRESSURE
1991 Mazda RX-7 Base, 2D Convertible, Standard
Fuel Pressure
1991 Mazda RX-7 Base, 2D Convertible, StandardSECTION Fuel Pressure
WARNING:
ALWAYS relieve fuel pressure before disconnecting any fuel injection related component. DO NOT allow fuel to contact engine or electrical components.
- On RX7, disconnect fuel pump connector at shock tower in trunk. On all others, disconnect circuit opening relay. See CIRCUIT OPENING RELAY LOCATIONS TABLE.
- To bleed down fuel in system, start engine (if possible) and allow to die. Connect pressure gauge to fuel line at fuel filter. Reconnect circuit opening relay.
- On Navajo, install EFI Pressure Gauge (T80L-9974-B) to relief valve. Relief valve is located on fuel supply manifold.
- Turn ignition on. Using a jumper wire, connect terminals of Yellow fuel pump check connector together. See FUEL PUMP CHECK CONNECTOR (YELLOW) LOCATIONS TABLE
. On Miata, Navajo, Protege and 323, jump test connector terminals Fp and ground. If pump runs, check fuel pump circuit, circuit opening relay, and fuel pump resistor (RX7).FUEL PUMP CHECK CONNECTOR (YELLOW) LOCATIONS
Application Location B2600i, Miata, MX-6, 323 & 626 On Firewall, Near Windshield Wiper Motor MPV, RX7 & 929 Near Airflow Sensor Navajo At Right Inner Fender Panel - If possible, start engine. Check fuel pressure with vacuum connected to and disconnected from pressure regulator. Turn engine off and disconnect jumper wire at fuel pump check connector. Wait 10 minutes and ensure residual pressure is at least 21 psi (1.5 kg/cm2 ).
- Operate fuel pump by jumpering fuel pump test connector. Check fuel pump performance. Pinch hose between pressure gauge and fuel filter. Do not hold longer than necessary to check pressure. See FUEL PUMP PERFORMANCE TABLE. If pump does not meet specifications, check fuel pump circuits, fuel pump, fuel tank, fuel filter or replace fuel pump.
FUEL PUMP PERFORMANCE
| Application | Pressure | ||||
|---|---|---|---|---|---|
| All Models (1) | (2) 64-85 psi (4.5-6.0 kg/cm2 ) | ||||
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REGULATED FUEL PRESSURE (AT IDLE)
| Application | W/Vacuum: psi (kg/cm2 ) | W/O Vacuum: psi (kg/cm2 ) |
|---|---|---|
| B2600i, Miata, MPV, Protege, 323 & 929 | 31-38 (2.2-2.7) | 38-46 (2.7-3.2) |
| MX-6, RX7 & 626 | 27-33 (1.9-2.3) | 34-40 (2.4-2.8) |
| Navajo | - | 34-46 (2.4-3.2) |
RENDER: 1.0x
NO RELATED
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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.