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.
1989 Mazda 929FACTORY OEM SERVICE PROCEDURE
Fuel Pressure
- On all V6 models, disconnect circuit opening relay (located behind left kick panel on 929). On MPV, relay is mounted on ECU. ECU is under protective cover on passenger side floor. Start engine (if possible) and allow to die. Connect pressure gauge to fuel line at fuel filter.
- Turn ignition on. Using a jumper wire, connect terminals of Yellow fuel pump check connector together. Fuel pump check connector is located on firewall, near airflow sensor on MPV and 929. If pump runs, check fuel pump circuit and circuit opening relay.
- 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 psi (kg/cm2 ) | Min. Vol. in 30 sec. Pts. (L) |
|---|---|---|
| MPV & 929 | 64-85 (4.5-6.0) | 1.1 (.66) |
REGULATED FUEL PRESSURE - AT IDLE
| Application | w/Vacuum psi (kg/cm2 ) | w/o Vacuum psi (kg/cm2 ) |
|---|---|---|
| MPV & 929 | 31-38 (2.2-2.7) | 38-46 (2.7-3.2) |
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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