1994 MAZDA MX-5 fuel

FUEL SYSTEM 1. Fuel filler hoses 7. Rear crossmem ber assembly 2. Fuel hoses Removal Note ............. page F-112 3. Evaporative hoses 8. Fuel tank unit 4. Fuel filter bolts 9. Two-way check valve ~4 Removal Note ............. page F-112 10. Fuel vapor valve 5. Brake pipe joint 11. Fuel pump Removal Note ............. page F-112 6. Battery cable Removal Note ............. page F-112 Removal note Fuel filter bolts 1. Remove the fuel filter cover. 2. Remove the fuel filter bolts. (MT) 3. Remove the fuel filter nuts. (AT) 4. Remove the fuel filter with the fuel hoses still connected. Brake pipe joint 1. Remove the brake pipe joint nuts. 2. Remove the brake pipe joint with the brake pipe and brake hose still connected. Battery cable Remove the battery cable clamp as shown in the figure. Rear crossmember assembly 1. Support the rear crossmember assembly with a trans- mission jack. 2. Remove the rear crossmember mounting bolts and nuts. 3. Lower the rear crossmember assembly. Gartner Banana

FUEL SYSTEM Installation note Fuel hoses and fuel filler hoses Push the ends of the main fuel hose, fuel return hose, and evaporation hose onto the fuel tank fittings L at least 25mm (1.0 in). Push the fuel filler hose onto the fuel tank pipe and filler pipe at least 35117171 (1.4 in). Power plant frame Install the power plant frame referring to the installation procedure on section J. FUEL FILTER Replacement Low-pressure side (In-tank filter) (Refer to page F-116.) High-pressure side The fuel filter must be replaced at the intervals outlined in the maintenance schedule. Warning Fuel vapor is hazardous. It can very easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Warning Fuel line spills and leaks are dangerous. Fuel can ~SJOFX-226 ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete the "Fuel Line Safety Procedures" on page F-108. 1. Raise the rear of the vehicle and support it with safety stands. 2. Remove the fuel filter protector. 3. Disconnect the fuel hoses from the fuel filter. 4. Remove the fuel filter and bracket. 5. Install in the reverse order of removal. 6. Verify that the fuel hoses are pushed fully onto the fuel filter nipples. Tightening torque: 7.9-10.7 N.m (80-110 kgfam, 70-95.4 in-lbf) Gartner Banana

F FUEL SYSTEM FUEL PUMP Inspection Fuel pump operation 1. Connect the data link connector terminals F/P and GND , with a jumper wire. 2. Remove the fuel filler cap. 3. Turn the ignition switch ON. 4. Listen for operational sound of the fuel pump at the filler inlet. 5. Install the fuel filler cap. 6. If no sound was heard, measure the voltage between the fuel pump connector wire to ground. Voltage: Battery positive voltage 7. If not correct, check the fuel pump relay and its circuits. (Refer to page F-116.) 8. If the voltage is normal, check for continuity between fuel pump connector (6) and a ground. 9. If there is continuity, replace the fuel pump. 10. If no continuity, repair the ground circuit. Hold pressure Perform this inspection if the fuel pressure hold inspec- tion is not as specified. (Refer to page F-109.) Warning Fuel line spills and leaks can be dangerous. Fuel can ignite and cause serious injuries or death and can damage the vehicle. Fuel can also irritate skin and eyes. To prevent this from happening, release the fuel pressure according to "Fuel Line Safety Procedures" on page F-108. 1. Disconnect the negative battery terminal. 2. Connect a fuel pressure gauge to the fuel main pipe and plug the outlet of the fuel pressure gauge as shown. (Install clamps as shown.) 3. Connect the negative battery terminal. Gartner Banana

FUEL SYSTEM 4. Connect data link connector terminals FIP and GND with a jumper wire. 5. Turn the ignition switch ON for 10 sec. to operate the fuel pump. 6. Turn the ignition switch OFF and disconnect the jumper wire. 7. Observe the fuel pressure after 5 min. Fuel pressure: More than 343 kPa (3.5 kgf/cm2, 50 psi) 8. If not as specified, replace the fuel pump. Fuel pump maximum pressure Warning Fuel line spills and leaks can be dangerous. Fuel can ignite and cause serious injuries or death and can damage the vehicle. Fuel can also irritate skin and eyes. To prevent this from happening, release the fuel pressure according to "Fuel Line Safety Procedures" on page F-108. 1. Disconnect the negative battery terminal. 2. Connect a fuel pressure gauge to the fuel main pipe and plug the outlet of the fuel pressure gauge as shown. (Install clamps as shown.) 3. Connect the negative battery terminal. 4. Connect data link connector terminals FIP and GND with a jumper wire. 5. Turn the ignition switch ON to operate the fuel pump. 6. Measure the pump maximum pressure. Fuel pump maximum pressure: 480-657 kPa (4.9-6.7 kgf/cm2, 69-95 psi) 7. Turn the ignition switch OFF and disconnect the jumper wire. 8. If not as specified, replace the fuel pump. Replacement Warning Fuel line spills and leaks can be dangerous. Fuel can ignite and cause serious injuries or death and can damage the vehicle. Fuel can also irritate skin and eyes. To prevent this from happening, release the fuel pressure according to "Fuel Line Safety Procedures" on page F-108. Gartner Banana

FUEL SYSTEM -- FUEL TANK GAUGE SENDER UNIT SIDE FUEL PUMP 45UOFX-256 1. Remove the rear package trim. 2. Remove the service hole cover. 3. Remove the fuel pump cover. 4. Disconnect the fuel pump connector. 5. Disconnect the fuel hoses. 6. Remove the fuel pump and fuel tank gauge sender unit assembly. 7. Remove the fuel pump. 8. Install in the reverse order of removal, referring to Instal- lation note. Installation note O-ring set 1. Use a new O-ring set. (O-ring, cap, and spacer) 2. Apply oil or fuel to the O-ring set before installing. 3. To confirm sealing of the O-ring, after assembling the fuel pump and fuel tank gauge sender unit, blow air through the fuel main pipe and verify that no air flows. If air flows the check ball may be stuck. Shake the fuel pump 2 or 3 times and recheck. Fuel pump After installing the fuel pump to the bracket, pull down the fuel pump down so that it is tight against the bracket. Gartner Banana

FUEL SYSTEM F FUEL PUMP RELAY Inspection Apply battery positive voltage and a ground to the termi- nals below and check the fuel pump relay operation as described. If not as specified, replace the fuel pump relay. B+: Battery positive voltage Replacement 1. Remove the undercover. B+ A 2. Remove the fuel pump relay. 3. Install in the reverse order of removal. Grounded B Correct result C - E: Continuity Gartner Banana

F FUEL SYSTEM PRESSURE REGULATOR Inspection Fuel line pressure d Warning Fuel line spills and leaks can be dangerous. Fuel can ignite and cause serious injuries or death and can damage the vehicle. Fuel can also irritate skin and eyes. To prevent this from happening, release the fuel pressure according to "Fuel Line Safety Procedures" on page F-108. 1. Disconnect the negative battery terminal. 2. Connect a fuel pressure gauge between the fuel main pipe and the fuel main hose. (Install clamps as shown.) 3. Connect the negative battery terminal. 4. Start the engine and run it at idle. 5. Measure the fuel line pressure. Fuel line pressure: 21 6-264 kPa (2.2-2.7 kgf/cm2, 32-38 psi) Hold pressure Perform this inspection if the fuel pressure hold inspec- tion is not as specified. (Refer to page F-104.) Warning Fuel line spills and leaks can be dangerous. Fuel ,-, can ignite and cause serious injuries or death and can damage the vehicle. Fuel can also irritate skin and eyes. To prevent this from happening, release the fuel pressure according to "Fuel Line Safety Procedures" on page F-108. 1. Disconnect the negative battery terminal. 2. Install a fuel pressure gauge between the fuel pipe and the fuel main hose. (Install clamps as shown.) 3. Connect the negative battery terminal. 4. Connect data link connector terminals F/P and GND with a jumper wire. 5. Turn the ignition switch ON for 10 sec. to operate the fuel pump. 6. Turn the ignition switch OFF and disconnect the jumper wire. 7. Block the outlet of the pressure regulator. 8. Observe the fuel pressure for 5 min. Fuel pressure: More than 147 kPa {I .5 kgf/cm2, 21 psi) 9. If pressure is as specified, replace the pressure regula- tor. Gartner Banana

FUEL SYSTEM F Replacement Warning Fuel line spills and leaks can be dangerous. Fuel can ignite and cause serious injuries or death and can damage the vehicle. Fuel can also irritate skin and eyes. To prevent this from happening, release the fuel pressure according to "Fuel Line Safety Procedures" on page F-108. 1. Disconnect the vacuum hose. 2. Disconnect the fuel return hose. 3. Remove the pressure regulator. Tightening torque: 7.9-10.7 N.m (80-11 0 kgf-cm, 70-95.4 in4bf) 4. Use new O-ring. 5. Install in the reverse order of removal. FUEL INJECTOR Inspection Operation check 1. Warm up the engine and run it at idle. 2. Listen for operational sound of the fuel injector with a screwdriver or a sound scope. 3. If no sound is heard, measure fuel injector resistance. 4. If the fuel injector resistance is OK, check wiring to the fuel injector and powertrain control module (engine) ter- minals 2U, 2V1 2Y and 22 voltages. (Refer to page F-147.) Fuel injector resistance 1. Disconnect the fuel injector harness. 2. Measure resistance of the fuel injector with an ohmme- ter. Resistance: 12-16Q (at 20°C (68°F)) 3. If not as specified, replace the fuel injector. Removal Warning Fuel line spills and leaks can be dangerous. Fuel can ignite and cause serious injuries or death and can damage the vehicle. Fuel can also irritate skin and eyes. To prevent this from happening, release the fuel pressure according to "Fuel Line Safety Procedures" on page F-108. Gartner Banana