Engine Controls - Basic Diagnostic Procedures: Diagnosis Mazda MX-5 NB рестайлинг

VISUAL INSPECTION

Visually inspect all electrical wiring, looking for chafed, stretched, cut or pinched wiring. Ensure electrical connectors fit tightly and are not corroded. Ensure vacuum hoses are properly routed and are not pinched or cut. See VACUUM DIAGRAMS article to verify routing and connections (if necessary). Inspect air induction system for possible vacuum leaks.

Fuel Line Pressure Inspection (Mazda6)

1. Disconnect negative battery cable. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-151876-S28315552622003010800000) . 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»(ref-151873-S08065964082003010800000) 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 .
2. Inspect fuel pressure regulator for restriction or sticking. Replace as necessary. If no problem is found, go to step 4 .
3. 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.
4. 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»(ref-151876-S04587443272003013000000) 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 .
5. 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»(ref-151876-S04776958142003010800000) 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»(ref-151892-S35967311232003010900000) under FUEL SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. Repair as necessary. After repair, go to next step.
6. Disconnect fuel pressure gauge. Complete «AFTER REPAIR PROCEDURE»(ref-151876-S01862095232003010800000) .

FUEL PRESSURE FLUCTUATION SPECIFICATIONS

FUEL HOLD PRESSURE SPECIFICATIONS

Fuel Line Pressure Inspection (Miata)

1. Disconnect negative battery cable. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-151876-S28315552622003010800000). Disconnect main fuel line from fuel rail near pulsation damper. Install Fuel Pressure Gauge (49-N013-1A0C) between main fuel line and fuel rail. Turn lever on fuel pressure gauge (Scheme 1) Reconnect negative battery cable. Ensure transmission is in neutral. Start engine and let idle. Measure fuel line pressure. For fuel pressure specifications, see «FUEL SYSTEM»(ref-151873-S08065964082003010800000) 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.
2. Inspect fuel pressure regulator for restriction or sticking. Replace as necessary. If no problem is found, go to step 4.
3. 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.
4. 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»(ref-151876-S04587443272003013000000) 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.
5. 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»(ref-151876-S04776958142003010800000) 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»(ref-151892-S35967311232003010900000) under FUEL SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. Repair as necessary. After repair, go to next step.
6. Disconnect fuel pressure gauge and reconnect main fuel line to fuel rail. Complete «AFTER REPAIR PROCEDURE»(ref-151876-S01862095232003010800000).

Fuel Line Pressure Inspection (MPV)

1. Disconnect negative battery cable. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-151876-S28315552622003010800000) . 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»(ref-151873-S08065964082003010800000) 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 .
2. Inspect fuel pressure regulator for restriction or sticking. Replace as necessary. If no problem is found, go to step 4 .
3. 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.
4. 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»(ref-151876-S04587443272003013000000) 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 .
5. 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»(ref-151876-S04776958142003010800000) 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»(ref-151892-S35967311232003010900000) under FUEL SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. Repair as necessary. After repair, go to next step.
6. Disconnect fuel pressure gauge. Complete «AFTER REPAIR PROCEDURE»(ref-151876-S01862095232003010800000) .

Scheme 1

Scheme 2

Scheme 3

1. Disconnect negative battery cable. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-151876-S28315552622003010800000). Disconnect main fuel line quick release connector from fuel rail near pulsation damper. Refer to «FUEL LINE CONNECTORS (MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5»(ref-151901-S13081098442003010900000) under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Install Fuel Pressure Gauge (49-N013-1A0C) between main fuel line and fuel rail. Turn lever on fuel pressure gauge (Scheme 1) Reconnect negative battery cable and go to next step.
2. Locate DLC-1 on left side of engine compartment. Connect a fused jumper wire between DLC-1 F/P terminal and body ground. (Scheme 2) Turn ignition on and pressurize fuel system. Inspect fuel line pressure. For fuel pressure specifications, see «FUEL SYSTEM»(ref-151873-S08065964082003010800000) in SERVICE & ADJUSTMENT SPECIFICATIONS article. If fuel line pressure is high, go to next step. If fuel line pressure is low, go to step 4.
3. Check fuel pump maximum pressure. See «FUEL PUMP PRESSURE INSPECTION (PROTEGE & PROTEGE5)»(ref-151876-S25820795382003013000000). If fuel pump maximum pressure is as specified, check for plugged or restricted fuel return line or fuel pressure regulator. Repair as necessary. After repair, go to step 6.
4. Check fuel line pressure for change while turning lever on fuel pressure gauge (Scheme 3) If fuel line pressure quickly increases, inspect fuel pressure regulator. If fuel line pressure gradually increases, inspect fuel pump maximum pressure. See «FUEL PUMP PRESSURE INSPECTION (PROTEGE & PROTEGE5)»(ref-151876-S25820795382003013000000). If fuel pump maximum pressure is normal, inspect for restriction between fuel pump and fuel pressure regulator. Repair as necessary. If no problem is found, go to next step.
5. Turn ignition on for 10 seconds to operate fuel pump. Turn ignition off and disconnect fused jumper wire. Wait 5 minutes and observe fuel pressure. See «FUEL HOLD PRESSURE SPECIFICATIONS»(ref-151876-S04776958142003010800000) table. Check for changes in fuel pressure while turning fuel pressure gauge lever (Scheme 3) If fuel pressure holds, replace fuel pressure regulator. If fuel pressure does not hold as specified, inspect for fuel leaks from fuel line and fuel injectors. See «FUEL CONTROL»(ref-151892-S35967311232003010900000) under FUEL SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. Repair as necessary. After repair, go to next step.
6. Disconnect fuel pressure gauge and reconnect main fuel line to fuel rail. Pull on main fuel line to ensure quick release fitting is engaged to fuel rail. Attach lock clip to quick release connector in direction of fuel rail and lock it. See «FUEL LINE CONNECTORS (MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5»(ref-151901-S13081098442003010900000) under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Complete «AFTER REPAIR PROCEDURE»(ref-151876-S01862095232003010800000).

Fuel Leakage Inspection

1. Turn ignition on to operate fuel pump.
2. Pressurize fuel system this way for at least 5 minutes to be sure of no leakage.
3. If there is fuel leakage, inspect fuel hoses, clamps, and fuel pipe sealing surface. Repair or replace as necessary.
4. After repair, reassemble fuel system and repeat steps 1 - 3 .

Fuel Line Pressure/Fuel Pressure Hold Inspection

Note. Fuel pump will only operate for about 8 seconds when Output Test Mode is selected and activated.

1. Check Fuel Pressure Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-151876-S28315552622003010800000) . Install Fuel Pressure Gauge (49-UN01-010). Turn ignition on, engine off. Connect scan tool to DLC. Select DIAGNOSTIC DATA LINK. Select PCM. Select ACTIVE COMMAND MODE. Select OUTPUT TEST MODE and FUEL PUMP PID. Press MODE to change to ALL ON MODE. Press START, to run fuel pump and observe fuel pressure. For fuel pressure specifications, see «FUEL SYSTEM»(ref-151873-S08065964082003010800000) in SERVICE & ADJUSTMENT SPECIFICATIONS article. If fuel pressure is as specified, go to next step. If fuel pressure reading is zero or low, check fuel pump. See «FUEL PUMP OPERATION»(ref-151876-S29945749962003013000000) . If fuel pump is okay, go to next step. If fuel pressure is high, go to step 3 .
2. Check Fuel Supply Line For Restriction Release fuel pressure. Disconnect fuel supply line at fuel rail. Disconnect fuel supply line at fuel pump. Check for restriction in fuel supply line (blockage, kinked or pinched). Using regulated air pressure of 3-5 psi (21-34 kPa), blow air through fuel supply line. If air flows freely, replace fuel pump. If air does not flow freely, repair restriction as necessary. Restore vehicle back to original condition and recheck fuel system.
3. Check Fuel Pressure After One Minute Turn fuel pump relay off and observe fuel pressure. Wait one minute. If fuel pressure reading is within 5 psi of previous pressure reading, fuel pressure hold inspection is okay. If fuel pressure drops more than 5 psi, inspect fuel injectors for leaks. Refer to «FUEL CONTROL»(ref-151890-S18356360452003010900000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - B2300, B3000, B4000 & TRIBUTE article.

Fuel Pressure Regulator Inspection (Tribute Only)

1. Check Fuel Pressure Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-151876-S28315552622003010800000) . Install Fuel Pressure Gauge (49-UN01-010). Start engine and run at idle. Disconnect vacuum hose from fuel pressure regulator and plug it. Drive vehicle under heavy acceleration while observing fuel pressure gauge reading. If fuel pressure holds steady within 3 psi (20.6 kPa), go to next step. If fuel pressure does not hold to within 3 psi (20.6 kPa), check fuel vapor valve. See «SYSTEM TESTS (EVAPORATIVE EMISSION)»(ref-134970-S09458215942002022100000) in SYSTEM & COMPONENT TESTING - B2300, B3000, B4000 & TRIBUTE article. If fuel vapor valve is okay, check for clogged fuel filter.
2. Check Fuel Pressure With Vacuum Applied To Regulator Connect vacuum pump to fuel pressure regulator. Apply vacuum to fuel pressure regulator. If fuel line pressure decreases when vacuum is applied, check vacuum hose and vacuum source. Repair as necessary. After repair, go to next step. If fuel pressure does not decrease when vacuum is applied, replace fuel pressure regulator. After repair, go to step 4 .
3. Check Fuel Pressure And Verify Fuel Flow Disconnect fuel return line from fuel rail. Connect a short hose from fuel rail to a one quart (one liter) measuring container. Turn ignition on, engine off. Connect scan tool to DLC. Select DIAGNOSTIC DATA LINK. Select PCM. Select ACTIVE COMMAND MODE. Select OUTPUT TEST MODE and FUEL PUMP PID. Press MODE to change to ALL ON MODE. Press START to run fuel pump. Measure fuel line pressure and verify fuel is flowing into container. If fuel pressure is still high, replace fuel pressure regulator. Restore vehicle to original condition. If fuel pressure is not high, inspect fuel return line for blockage or clog. Repair or replace as necessary. After repair, go to next step.
4. Check Regulator For Fuel Leaks Start engine and run at idle for 10 seconds. Turn ignition off for 10 seconds. Start engine and run at idle for 10 seconds. Turn ignition off. Disconnect vacuum hose from pressure regulator. If diaphragm is leaking fuel, replace fuel pressure regulator. Restore vehicle to original condition. If fuel is not leaking from diaphragm, restore vehicle to original condition. Testing is complete.

Scheme 4

Scheme 5

1. Check Fuel Pump For Operation Verify battery is fully charged. Verify fuel tank unit 4-pin harness connector is securely connected. Turn ignition on, engine off. Connect scan tool to DLC. Select DIAGNOSTIC DATA LINK. Select PCM. Select ACTIVE COMMAND MODE. Select OUTPUT TEST MODE and fuel pump PID. Press MODE to change to ALL ON MODE. Press START to run fuel pump and listen for fuel pump operation. Press STOP. If fuel pump operation was heard, go to «FUEL DELIVERY SYSTEM»(ref-151876-S10041695972003060400000) for more trouble shooting procedures. If fuel pump operation is not heard, go to next step.
2. Check Fuel Pump For Continuity Turn ignition off. Disconnect fuel tank unit 4-pin harness connector. (Scheme 4)or (Scheme 5). Check for continuity between fuel tank unit 4-pin connector power terminal (Pink/Black wire) and ground terminal (Black wire). See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. If continuity is present, go to next step. If continuity is not present, replace fuel pump.
3. Check Voltage At Fuel Pump (Vehicle Harness Connected) Turn ignition on, engine off. Select DIAGNOSTIC DATA LINK. Select PCM. Select ACTIVE COMMAND MODE. Select OUTPUT TEST MODE. On Tribute, select FUEL PUMP PID. On all models, press MODE to change to ALL ON MODE. Press START to run fuel pump. Measure voltage at fuel tank unit 4-pin connector power terminal (Pink/Black wire). Press STOP. If voltage is more than 10.5 volts, go to next step. If voltage reading is 10.5 volts or less, check fuel pump relay or Inertia Fuel Shut-off (IFS) switch.
4. Check Fuel Pump Ground Circuit With fuel tank assembly 4-pin harness connector disconnected. (Scheme 4)or (Scheme 5). Measure resistance between fuel tank unit 4-pin connector ground terminal (Black wire) and chassis ground. If resistance is less than one ohm, ground circuit is okay. Recheck fuel pump. If resistance reading is one ohm or more, repair open circuit in Black wire between fuel tank assembly 4-pin harness connector and chassis ground.

Scheme 6

Scheme 7

1. Disconnect negative battery cable. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-151876-S28315552622003010800000). Disconnect quick release connector on fuel inlet hose near fuel rail. (May require removal of battery and battery tray.) Refer to «FUEL LINE CONNECTORS (MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5»(ref-151901-S13081098442003010900000) under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Install fuel pressure gauge to fuel inlet hose from fuel tank. (Scheme 6) Turn lever 90 degrees against hose of fuel pressure gauge to plug gauge outlet line. Go to next step.
2. Locate check connector in underhood main fuse block. (Scheme 7) Connect a fused jumper wire between check connector F/P terminal and body ground. Turn ignition on for 10 seconds to operate fuel pump. Turn ignition to LOCK position. Wait 5 minutes and observe fuel pressure. See «FUEL PUMP HOLD PRESSURE SPECIFICATIONS»(ref-151876-S40540954222003010800000) table. If fuel pump hold pressure is not as specified, check for restriction or leaks in fuel line. Repair as necessary. After repair, go to next step. If no problems are found, replace fuel pump. After repair, go to next step.
3. Disconnect fused jumper wire. Disconnect fuel pressure gauge and reconnect fuel line quick release connector. Reinstall battery and battery tray if required. Complete «AFTER REPAIR PROCEDURE»(ref-151876-S01862095232003010800000).

FUEL PUMP HOLD PRESSURE SPECIFICATIONS

Fuel Pump Pressure Inspection (Miata)

1. Disconnect negative battery cable. Raise vehicle and support with safety stands. Remove fuel filter cover. Disconnect quick release fuel line connector. Refer to «FUEL LINE CONNECTORS (MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5»(ref-151901-S13081098442003010900000) under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Install Fuel Pressure Gauge (49-N013-1A0C) onto fuel filter fitting until click is heard. Pull quick release connector by hand and ensure fuel line is installed securely. Turn lever on fuel pressure gauge to plug gauge outlet. Go to next step.
2. Reconnect negative battery cable. Connect a fused jumper wire between DLC-1 F/P terminal and body ground. (Scheme 2) Turn ignition on to operate fuel pump and observe fuel pressure. See «FUEL PUMP MAXIMUM PRESSURE SPECIFICATIONS»(ref-151876-S02942756112003010800000) table. If fuel pressure is not as specified, turn ignition to LOCK position and check following: Fuel pump. Fuel pump relay. Fuel filter for clogging. Fuel line for restriction or leakage. If problem is found, repair as necessary. After repair, go to step 4. If no problem is found go to next step.
3. Turn ignition on for 10 seconds to operate fuel pump. Turn ignition back to LOCK position. Wait 5 minutes and observe fuel pressure. See «FUEL PUMP HOLD PRESSURE SPECIFICATIONS»(ref-151876-S40540954222003010800000) table. If fuel pump hold pressure is not as specified, replace fuel pump. After repair, go to next step.
4. Disconnect fused jumper wire. Disconnect fuel pressure gauge and reconnect fuel line to fuel filter. Pull quick release connector by hand and ensure fuel line is installed securely. Complete «AFTER REPAIR PROCEDURE»(ref-151876-S01862095232003010800000).

FUEL PUMP MAXIMUM PRESSURE SPECIFICATIONS

Fuel Pump Pressure Inspection (MPV)

1. Disconnect negative battery cable. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-151876-S28315552622003010800000). Disconnect quick release connector on fuel inlet hose near fuel rail. (May require removal of air cleaner.) Refer to «FUEL LINE CONNECTORS (MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5»(ref-151901-S13081098442003010900000) under FUEL SYSTEM in REMOVAL OVERHAUL & INSTALLATION article. Install fuel pressure gauge to fuel inlet hose from fuel tank. (Scheme 6) Turn lever 90 degrees against hose of fuel pressure gauge to plug gauge outlet line. Go to next step.
2. Connect a fused jumper wire between DLC-1 F/P terminal and body ground. Turn ignition to operate fuel pump. Measure fuel pump maximum pressure. For fuel pressure specifications, see «FUEL SYSTEM»(ref-151873-S08065964082003010800000) in SERVICE & ADJUSTMENT SPECIFICATIONS article. If fuel pressure is not as specified, inspect following: Fuel pump. Fuel pump relay. Fuel filter for clogging. Fuel line for restriction or leakage. If problem is found, repair as necessary. If no problem is found go to next step.
3. Turn ignition on for 10 seconds to operate fuel pump. Turn ignition to LOCK position. Wait 5 minutes and observe fuel pressure. See «FUEL PUMP HOLD PRESSURE SPECIFICATIONS»(ref-151876-S40540954222003010800000) table. If fuel pump hold pressure is not as specified, check for restriction or leaks in fuel filter and fuel line. Repair as necessary. After repair, go to next step. If no problems are found, replace fuel pump. After repair, go to next step.
4. Disconnect fused jumper wire. Disconnect fuel pressure gauge and reconnect fuel line quick release connector. Reinstall air filter if required. Complete «AFTER REPAIR PROCEDURE»(ref-151876-S01862095232003010800000).

Fuel Pump Pressure Inspection (Protege & Protege5)

1. Disconnect negative battery cable. Disconnect quick release fuel line connector from fuel rail (near pulsation damper). Refer to «FUEL LINE CONNECTORS (MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5»(ref-151901-S13081098442003010900000) under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Install Fuel Pressure Gauge (49-N013-1A0C) onto main fuel line until click is heard. Pull quick release connector by hand and ensure fuel line is installed securely. Turn lever on fuel pressure gauge (Scheme 3) Go to next step.
2. Reconnect negative battery cable. Connect a fused jumper wire between DLC-1 F/P terminal and body ground. (Scheme 2) Turn ignition on to operate fuel pump and observe fuel pressure. For fuel pressure specifications, see «FUEL SYSTEM»(ref-151873-S08065964082003010800000) in SERVICE & ADJUSTMENT SPECIFICATIONS article. If fuel pressure is not as specified, turn ignition off and check following: Fuel pump relay. Fuel filters (low and high pressure) for clogging. Fuel line for restriction or leakage. If problem is found, repair as necessary. After repair, go to step 4. If no problem is found, go to next step.
3. Turn ignition on for 10 seconds to operate fuel pump. Turn ignition off. Wait 5 minutes and observe fuel pressure. See «FUEL PUMP HOLD PRESSURE SPECIFICATIONS»(ref-151876-S40540954222003010800000) table. If fuel pump hold pressure is not as specified, perform fuel pressure regulator and fuel injector inspection. Refer to «FUEL PRESSURE REGULATOR INSPECTION»(ref-151876-S14190129032003010800000) or «FUEL CONTROL»(ref-151892-S35967311232003010900000) under FUEL SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If no problem is found, replace fuel pump. After repair, go to next step.
4. Disconnect fused jumper wire. Disconnect fuel pressure gauge and reconnect fuel line to fuel rail. Pull quick release connector by hand and ensure fuel line is installed securely. Complete «AFTER REPAIR PROCEDURE»(ref-151876-S01862095232003010800000).

Fuel Pressure Regulator Inspection

1. Disconnect negative battery cable. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-151876-S28315552622003010800000) . Install fuel pressure gauge in fuel supply line. Reconnect negative battery cable.
2. Start and operate engine at idle. Ensure vacuum is available to pressure regulator. Observe fuel pressure with vacuum hose connected and disconnected at fuel pressure regulator. For fuel pressure specifications, see «FUEL SYSTEM»(ref-151873-S08065964082003010800000) in SERVICE & ADJUSTMENT SPECIFICATIONS article. If fuel pressure is not as specified, replace fuel pressure regulator.