Fuel Line Pressure Inspection (Mazda6)
- Disconnect negative battery cable. Release fuel pressure. See FUEL PRESSURE RELEASE . Disconnect negative battery cable. Ensure lever of Fuel Pressure Gauge (49-UN01-010) is turned fully clockwise (closed position). Install fuel pressure gauge to Schrader valve. Reconnect negative battery cable. Ensure transaxle is in neutral. Start engine and let idle. Measure fuel line pressure. For fuel pressure specifications, see FUEL SYSTEM
in SERVICE & ADJUSTMENT SPECIFICATIONS article. If fuel line pressure is high, go to next step. If fuel line pressure is low, go to step 3.
- Inspect fuel pressure regulator for restriction or sticking. Replace as necessary. If no problem is found, go to step 4.
- Inspect fuel pressure regulator for internal leak, fuel pump circuit and fuel pump. Repair or replace as necessary. If no problem is found, go to next step.
- Start engine and let idle. Observe fuel pressure during heavy acceleration. Ensure fuel pressure fluctuation is within specification during test. See FUEL PRESSURE FLUCTUATION SPECIFICATIONS table. If fuel pressure fluctuation is as specified, go to step 6. If fuel pressure fluctuation is not as specified, inspect following:
- PCM.
- Fuel pump.
- Fuel pulsation damper.
- Fuel line for improper routing, kinks or damage.
If no problem is found, go to next step. If problem is found, repair as necessary. After repair, go to step 6.
- Start engine and let idle for 10 seconds. Turn ignition to LOCK position. Measure fuel hold pressure after 5 minutes. See FUEL HOLD PRESSURE SPECIFICATIONS table. If fuel hold pressure is as specified, go to next step. If fuel hold pressure is not as specified, check for fuel line or fuel injector leaks. Refer to FUEL CONTROL
under FUEL SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. Repair as necessary. After repair, go to next step.
- Disconnect fuel pressure gauge. Complete AFTER REPAIR PROCEDURE .
FUEL PRESSURE FLUCTUATION SPECIFICATIONS
| Application |
Pressure psi (kPa) |
| Mazda6 |
| 2.3L |
54-64 (372-441) |
| 3.0L |
61-74 (421-510) |
| Miata |
53-61 (365-421) |
| MPV |
61-66 (421-455) |
FUEL HOLD PRESSURE SPECIFICATIONS
| Application |
Pressure psi (kPa) |
| Mazda6 |
| 2.3L |
28 (193) |
| 3.0L |
36 (248) |
| Miata |
36 (248) |
| MPV |
26 (179) |
| Protege |
21 (145) |