Engine Controls - Remove/install/overhaul Mazda 323 BG

INTRODUCTION

Removal, overhaul and installation procedures are covered in this article. If component removal and installation is primarily an unbolt and bolt-on procedure, only a torque specification may be furnished.

Note. On Miata, obtain code number and deactivate anti-theft alarm before disconnecting battery cable.

DISTRIBUTOR

Note. Miata and Navajo are equipped with distributorless ignition system.

Refer to appropriate illustration when removing, overhauling or installing distributor. (Scheme 1)- (Scheme 8).

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Removal & Installation (Miata & 929)

Disconnect sensor connector. Remove hold-down bolt. Remove sensor. To install, reverse removal procedure. Adjust ignition timing. See ADJUSTMENTS article. Tighten bolt to specification. See TORQUE SPECIFICATIONS table at end of article.

Removal & Installation (MX-3 DOHC)

Disconnect negative battery cable. Remove idle pulley bracket. Remove dipstick pipe. Disconnect sensor connector. Remove sensor. To install, reverse removal procedure. Tighten bolts to specification. See TORQUE SPECIFICATIONS table at end of article. Adjust ignition timing. See ADJUSTMENTS article.

Removal & Installation (Navajo)

Disconnect negative battery cable. Disconnect crankshaft timing (variable reluctance) sensor connector. (Scheme 9) Remove crankshaft timing sensor mounting screws, and remove sensor. To install, reverse removal procedure. Tighten screws to specification. See TORQUE SPECIFICATIONS table at end of article.

Scheme 9

FUEL SYSTEM

Except Navajo

1. Start engine. On B2200 PFI, B2600i, Miata,MX-6, 626 and 929, disconnect circuit opening relay. See CIRCUIT OPENING RELAY LOCATION table. On MPV 3.0L, disconnect airflow sensor connector.
2. On all other models, disconnect fuel pump connector near fuel tank (on MX-3, Protege and 323, fuel pump connector is accessible from under rear seat cushion).
3. On all models, allow engine to run until it stalls. Turn ignition off. Reconnect electrical connector.

CIRCUIT OPENING RELAY LOCATION

Navajo

1. Disconnect negative battery cable. Remove snow/ice shield. Remove air intake tube between air cleaner and throttle body. Remove fuel filler cap to release fuel tank pressure. Connect Fuel Pressure Gauge (49-UN01-010) to relief valve (Schrader valve) on fuel supply manifold, near fuel pressure regulator. (Scheme 27)
2. As an alternate method, disconnect inertia switch connector, behind instrument panel, under radio. Start engine, and operate it until it stalls.

FUEL LINE CONNECTORS (NAVAJO)

Note. Although push-connect fittings and spring lock couplers are similar in function, different procedures and tools are used to disconnect and connect these connectors. To identify type of connector (Scheme 10)and (Scheme 11).

Scheme 10

1. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE. Remove locking (safety) clip (if equipped).
2. Position Push-Connect Fitting Releaser (49-UN01-053 for 5/16" line; 49-UN01-054 for 3/8" line) over fuel line. (Scheme 10) Slide releaser into fitting. Pull fuel lines apart.

Connect (Push-Connect Fitting)

Press fuel lines together until a click is heard. Attempt to pull lines apart to ensure coupler is fully engaged. Install locking clip (if equipped).

Scheme 11

1. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE. Remove locking (safety) clip (if equipped). Place Spring Lock Coupler Releaser (49-UN01-051 for 3/8" line; 49-UN01-052 for 1/2" line) over fuel line coupler. (Scheme 11)
2. Push spring lock coupler releaser to release female fitting from garter spring. Pull spring lock coupler apart. Remove releaser.

Connect (Spring Lock Coupler)

1. Check for damaged garter spring. If garter spring is damaged, remove using small hooked wire and replace spring. Wipe end of lines using clean cloth. Place new "O" rings onto tube. Lubricate ends of lines with clean refrigerant oil.
2. Push fitting together using a slight twisting motion. Ensure garter spring is over flared end of female fitting. Attempt to pull lines apart to ensure coupler is fully engaged. Install locking clip (if equipped).

FUEL SYSTEM PRIMING

1. On B2200 PFI, B2600i, MPV, MX-6 and 626, connect jumper wire between terminals of Yellow 2-pin connector. See FUEL PUMP TEST CONNECTOR LOCATION table.
2. On Miata, MX-3, Protege, 323 and 929, connect jumper wire between GRD and F/P terminals of diagnostic connector. (Scheme 12) On all models, turn ignition on for about 10 seconds and then off. Disconnect jumper wire.

Without starting engine, turn ignition on and off 5-10 times.

FUEL PUMP TEST CONNECTOR LOCATION

Scheme 12

Removal & Installation

Disconnect negative battery cable. Remove air cleaner. Disconnect accelerator cable, cruise control cable (if equipped), all necessary vacuum hoses, fuel hoses and electrical connectors. Remove carburetor mounting nuts. Remove carburetor. To install, reverse removal procedure.

Disassembly (Air Horn & Choke Assembly)

1. DO NOT remove choke valve and shaft from air horn. Disconnect vacuum hose from choke opener (pull-off) diaphragm. Remove accelerator pump connecting rod, spring and lever. (Scheme 23) Remove spring. Disconnect air vent solenoid valve wire from connector.
2. Disconnect choke rod. Remove air horn retaining bolts. Remove air horn and choke assembly from main body. Remove air vent solenoid valve, spring and gasket from air horn.

Disassembly (Needle Valve & Float)

Remove float, pin and gasket. (Scheme 16)and (Scheme 23). Remove needle valve assembly. Remove sight glass assembly from main body.

Scheme 13

Scheme 14

1. Remove secondary slow jet, secondary slow bleed, secondary main bleed and secondary main jet from main body. (Scheme 13)and (Scheme 23). Remove primary main bleed, slow jet and plug, primary slow bleed and primary main jet from main body.
2. Remove richer air bleed, primary slow bleed, coasting richer air bleed and coasting richer jet from air horn. (Scheme 14)and (Scheme 23).

Disassembly (Main Body)

1. DO NOT remove venturis from main body. Remove coasting richer solenoid valve and "O" ring. (Scheme 23) Remove idle switch and spring. Remove slow fuel-cut solenoid valve, needle valve, spring and gasket. Remove dashpot (M/T).
2. Remove accelerator pump plunger and spring assembly. Remove retaining clip, strainer and inlet check ball. Remove outlet check ball plug, outlet check ball and spring.
3. Disconnect throttle link, vacuum diaphragm connecting rod and throttle return spring. Remove throttle body-to-main body retaining bolts (one bolt is located inside throttle body). Separate throttle body from main body.

Disassembly (Throttle Body)

DO NOT remove throttle valve and shaft from throttle body. Remove vacuum (secondary) diaphragm assembly. Remove diaphragm cover screws. Remove cover, spring and diaphragm. Using small punch and hammer, remove spring pin located in front of mixture adjusting screw. Remove mixture adjusting screw.

Note. DO NOT immerse diaphragms, electrical components or synthetic parts in carburetor cleaner.

Scheme 15

1. Thoroughly clean parts in carburetor cleaner. Using compressed air, dry all components and blow out all passages. DO NOT use wire or pointed metal objects for cleaning. Inspect air horn, main body and throttle body for cracks.
2. Inspect choke shaft and throttle shaft for wear. Check all jets and air bleeds for open passages. Inspect needle and seat for wear. Inspect float and accelerator pump cup for damage. Replace all damaged components.
3. Inspect vacuum diaphragm for damage. Inspect idle mixture screw for wear and burrs. Apply battery voltage to solenoids to ensure solenoids operate (indicated by valve stem movement).
4. Check electric choke heater by connecting an ohmmeter to wire connector and heater ground. If continuity does not exist, replace electric choke heater.
5. To check Air/Fuel (A/F) solenoid valve, apply battery voltage across solenoid using solenoid connector. (Scheme 15) From bottom of air horn, blow air through valve in direction indicated. (Scheme 15) If air does not flow through valve with solenoid energized, replace air horn assembly (air/fuel solenoid and air horn are replaced as an assembly).

Reassembly (All Parts)

1. To reassemble, reverse disassembly procedure using NEW gaskets. DO NOT install spring pin in front of mixture screw until idle mixture has been adjusted with engine running. Before installing air horn on main body, adjust float level and float drop. Install NEW "O" ring on air/fuel solenoid valve and coat "O" ring with gasoline.
2. After reassembly and before installing carburetor, adjust choke pull-off diaphragm, fast idle cam (throttle opening angle), fast idle cam (choke opening angle), choke unloader, secondary throttle valve and accelerator cable.
3. After installing carburetor, adjust curb (hot) idle speed, fast (cold) idle speed and idle mixture. See ADJUSTMENTS article.

Adjusting Float Level

With air horn upside-down and gasket removed, allow float to hang by its weight. Measure distance between top of float and air horn gasket surface. (Scheme 16) If distance is not.42-.46" (10.7-11.7 mm) on A/T models or.46-.50" (11.7-12.7 mm) on M/T models, bend float seat as necessary.

Scheme 16

Adjusting Float Drop

With air horn upright and gasket removed, allow float to hang by its weight. Measure between bottom of float and air horn gasket surface. (Scheme 17) If distance is not 1.81-1.85" (46.0-47.0 mm), bend float stop as necessary. (Scheme 16)

Scheme 17

Adjusting Choke Pull-Off Diaphragm

Apply about 16 in. Hg vacuum to choke pull-off diaphragm. Lightly push choke plate toward closed position. Measure clearance between top of choke plate and air horn. (Scheme 18) If clearance is not.067-.085" (1.70-2.16 mm), bend choke lever until clearance is within specification.

Scheme 18

Adjusting Fast Idle Cam (Throttle Opening Angle)

Set fast idle cam on second highest position. Measure between primary throttle valve and throttle bore. If clearance is not.033-.041" (0.84-1.04 mm), turn fast idle adjusting screw as necessary. (Scheme 19)

Scheme 19

Adjusting Fast Idle Cam (Choke Opening Angle)

Set fast idle cam on second highest position. Measure clearance between top of choke plate and air horn. (Scheme 20) If clearance is not.024-.045 (0.60-1.14), bend starting arm. If large adjustment is required, bend choke rod.

Scheme 20

Adjusting Choke Unloader

Fully open primary throttle valve. Measure clearance between top of choke plate and air horn. (Scheme 21) If clearance is not.110-.143" (2.80-3.62 mm), bend tab as necessary.

Scheme 21

Adjusting Secondary Throttle Valve

Secondary throttle valve should start to open when primary throttle valve opens 50-54 degrees and should be fully open when primary throttle valve is fully open. Measure clearance between primary throttle valve and throttle bore when secondary throttle valve starts to open. (Scheme 22) If clearance is not.289-.325" (7.35-8.25 mm), bend tab as necessary.

Scheme 22

Adjusting Accelerator Cable

Check accelerator cable deflection (free play) at carburetor. If deflection is not .039-.118" (1.0-3.0 mm), turn cable adjusting nuts as needed. Fully depress accelerator pedal. If primary throttle valve does not fully open, turn accelerator stop bolt (above accelerator pedal) as needed to obtain full valve opening.

Scheme 23

FUEL PUMP

Removal & Installation (B2200 Carbureted With Electric Pump, B2200 PFI & B2600i)

Release fuel system pressure (except B2200 Carbureted). See FUEL SYSTEM PRESSURE RELEASE. Remove fuel tank. Remove fuel pump and sending unit assembly. Remove fuel pump from assembly. To install, reverse removal procedure.

Removal (Miata, Protege & 323)

1. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE.
2. On Miata, remove rear package trim (behind seat) and service hole cover. On Protege and 323, remove rear seat.
3. On all models, remove fuel pump cover. Disconnect fuel hoses and electrical connector. Remove fuel pump and sending unit assembly. Remove fuel pump from assembly.

Scheme 24

1. Install fuel pump to assembly using NEW "O" ring, cap and spacer between fuel pump and outlet pipe (coat components with oil or gasoline before installing). (Scheme 24) After installing fuel pump to assembly, blow through outlet pipe (at top of assembly) toward pump to confirm sealing of "O" ring.
2. If air flows through pump, shake pump several times to dislodge check ball. To complete installation, reverse removal procedure.

Removal (MPV & MX-3)

1. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE. Remove rear seat. On MPV, lift rear floor mat.
2. On all models, remove fuel pump cover. Disconnect fuel hoses and electrical connector. Remove fuel pump and sending unit assembly. Remove fuel pump from assembly.

Installation

1. Replace fuel hose between pump and outlet pipe (DO NOT apply excessive force when installing onto pump nipple). Install hose clamps so each clamp is located.1" (3 mm) from end of hose, and hose clamp tabs are positioned around circumference of hose. (Scheme 25)
2. Install pump with terminals positioned in relation to assembly frame. To complete installation, reverse removal procedure.

Scheme 25

Removal & Installation (MX-6, 626 & 929)

1. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE.
2. On MX-6 and 626, remove rear seat and service hole cover. On 929, remove amplifier and CD changer (if equipped) and lift rear floor mat.
3. On all models, disconnect fuel hoses and electrical connector. Remove fuel pump and sending unit assembly. Remove fuel pump from assembly. To install, reverse removal procedure.

Removal (Navajo)

Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE. Remove fuel tank. Using Fuel Tank Lock Ring Wrench (T86T-9275-A), turn lock ring counterclockwise. Remove lock ring. Remove fuel pump and sending unit assembly. Remove fuel pump from assembly.

Clean seal area on tank and assembly flange. Lightly coat NEW "O" ring with molybdenum grease. Install seal in groove. Carefully install assembly into fuel tank, ensuring filter is not damaged and seal remains in groove. Install and turn lock ring clockwise until tight using Fuel Tank Lock Ring Wrench (T86T-9275-A). Install fuel tank.

FUEL PRESSURE REGULATOR

Removal & Installation (Except Navajo)

1. Disconnect negative battery cable. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE. On MX-6, 626 and 929, remove dynamic chamber. On all models, disconnect vacuum and fuel hose(s) from regulator. Remove regulator mounting bolts. Remove regulator, gasket and "O" ring (if equipped).
2. To install, reverse removal procedure. Install NEW gasket and "O" ring (if equipped). On MX-6, 626 and 929, install dynamic chamber with NEW gasket. Tighten bolts to specification. See TORQUE SPECIFICATIONS table at end of article.

1. Disconnect negative battery cable. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE. Disconnect vacuum hose from regulator. Disconnect fuel line coupling at regulator. See FUEL LINE CONNECTORS (NAVAJO).
2. Remove regulator mounting screws. Remove regulator, "O" ring and washer. To install, reverse removal procedure using NEW washer and "O" ring. Lubricate NEW "O" ring with light oil. DO NOT use silicone grease.

FUEL RAILS & INJECTORS

Removal & Installation (B2200 PFI, B2600i & MPV 2.6L)

1. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE under FUEL SYSTEM. Remove throttle body. See THROTTLE BODY under FUEL SYSTEM.
2. Remove support brackets and injector harness bracket from dynamic chamber. Disconnect vacuum hoses, PCV hose, intake air thermosensor connector and ground wire from dynamic chamber. Remove dynamic chamber.
3. Disconnect vacuum hose and fuel hoses from fuel rail. Disconnect injector electrical connectors. Pull fuel rail with injectors and pressure regulator upward to remove. Remove insulators, injectors and "O" rings from fuel rail.
4. To install, reverse removal procedure. Apply coat of engine oil to NEW "O" rings, and install rings on injectors. Install NEW insulators. Tighten fuel rail mounting bolts to specification. See TORQUE SPECIFICATIONS table at end of article. Install dynamic chamber with NEW gasket.

Removal & Installation (Miata)

1. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE. Disconnect negative battery cable. Remove air valve and PCV valve hose from intake manifold. Disconnect vacuum and fuel hoses from fuel rail. Disconnect injector electrical connectors. Remove insulators, injectors and "O" rings from fuel rail.
2. To install, reverse removal procedure. Apply coat of engine oil to NEW "O" rings and install rings on injectors. Install NEW insulators. Tighten fuel rail mounting bolts to specification. See TORQUE SPECIFICATIONS table at end of article.

Scheme 26

1. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE. Remove air intake tube. (Scheme 26) Remove throttle body. See THROTTLE BODY.
2. Remove intake air pipe, extension manifolds and dynamic chamber. Disconnect fuel hoses from fuel rail. Disconnect injector electrical connectors. Remove fuel rail and injectors as an assembly. Remove insulators, injectors and "O" rings from fuel rail.
3. To install, reverse removal procedure. Apply coat of engine oil to NEW "O" rings, and install rings on injectors. Install NEW insulators. Tighten fuel rail mounting nuts to specification. See TORQUE SPECIFICATIONS table at end of article. Install NEW extension manifold and intake air pipe gaskets.

1. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE. Disconnect negative battery cable. Remove air intake tube. Disconnect vacuum and fuel hoses from fuel rail. Disconnect injector electrical connectors. Remove fuel rail, injectors and pressure regulator as an assembly. Remove insulators, injectors and "O" rings from fuel rail.
2. To install, reverse removal procedure. Apply coat of engine oil to NEW "O" rings and install rings on injectors. Install NEW insulators. Tighten fuel rail mounting bolts to specification. See TORQUE SPECIFICATIONS table at end of article.

Removal & Installation (MX-3 SOHC, Protege & 323)

1. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE. Disconnect injector electrical connectors. Remove injector harness from fuel rail. Remove fuel rail mounting bolts. Remove fuel rail, injectors and pressure regulator as an assembly.
2. Remove insulators, injectors and "O" rings from fuel rail. To install, reverse removal procedure. Apply coat of engine oil to NEW "O" rings and install rings on injectors. Install NEW insulators. Tighten fuel rail mounting bolts to specification. See TORQUE SPECIFICATIONS table at end of article.

Removal & Installation (MX-6 & 626)

1. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE. Remove dynamic chamber. Disconnect fuel return pipe from intake manifold. Disconnect injector electrical connectors. Remove fuel rail, injectors, pressure regulator and pulsation damper as an assembly.
2. Remove insulators, injectors and "O" rings from fuel rail. To install, reverse removal procedure. Apply coat of engine oil to NEW "O" rings and install rings on injectors. Install NEW insulators. Tighten fuel rail mounting bolts to specification. See TORQUE SPECIFICATIONS table at end of article.

1. Thoroughly clean engine. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE. Disconnect negative battery cable. Remove upper intake manifold and throttle body as an assembly.
2. Disconnect fuel supply line from fuel supply manifold. See FUEL LINE CONNECTORS (NAVAJO). Disconnect fuel return line from fuel pressure regulator. Remove fuel supply manifold. (Scheme 27) Disconnect injector electrical connectors. Remove injectors from fuel supply manifold.

Scheme 27

1. If injectors were removed, lubricate NEW injector "O" rings with light oil. DO NOT use silicone grease. Carefully install injectors into fuel supply manifold. Carefully install fuel supply manifold into lower manifold using NEW manifold gasket.
2. Clean and oil fuel supply manifold bolt threads. Install fuel supply manifold bolts. Tighten bolts to specification. See TORQUE SPECIFICATIONS table at end of article. To complete installation, reverse removal procedure.

Removal & Installation (929)

1. Disconnect negative battery cable. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE. Remove dynamic chamber and throttle body as an assembly. Disconnect injector electrical connectors. Disconnect vacuum and fuel hoses. Remove fuel rail, injectors and pressure regulator as an assembly.
2. Remove insulators, injectors and "O" rings from fuel rail. To install, reverse removal procedure. Apply coat of engine oil to NEW "O" rings, and install rings on injectors. Install NEW insulators. Tighten fuel rail mounting bolts to specification. See TORQUE SPECIFICATIONS table at end of article.

Removal

Disconnect O2 sensor electrical connector. Sensor may be difficult to remove when engine temperature is less than 120°F (48°C). If sensor is difficult to remove, use rust penetrant to avoid damaging threads. Carefully remove sensor.

Apply anti-seize to sensor threads (if reusing old sensor or if new sensor is not coated with anti-seize). Install sensor. See TORQUE SPECIFICATIONS table at end of article. Reconnect sensor electrical connector.

THROTTLE BODY

1. On MPV 3.0L, drain about 2 qts. (1.9 L) of coolant from cooling system. On all models, disconnect negative battery cable. Remove air intake tube.
2. Disconnect accelerator cable, coolant hoses and electrical connectors from throttle body as necessary. On 929, remove by-pass air control valve. On all models, remove throttle body. To install, reverse removal procedure using NEW throttle body gasket. See TORQUE SPECIFICATIONS table at end of article.

1. Disconnect electrical connectors at air by-pass valve, throttle position sensor and air charge temperature sensor. Remove snow/ice shield to expose throttle linkage. Remove throttle cable bracket.
2. Disconnect cable from ball stud on throttle body. Remove air cleaner-to-throttle body air inlet tube. Disconnect upper intake manifold vacuum connectors. Disconnect PCV valve from rocker cover.
3. Disconnect spark plug wires at rear of manifold. Remove canister purge line from fitting in throttle housing. Remove A/C line-to-upper manifold bolt. Remove 6 upper manifold retaining bolts. Remove upper intake and throttle body (as an assembly) from lower intake and fuel supply manifolds.

Clean and oil manifold bolt threads. Install NEW manifold gasket. If injectors were removed, lubricate NEW injector "O" rings with a light oil. DO NOT use silicone grease. To complete installation, reverse removal procedure.

Scheme 28

1. Drain coolant. Remove air hoses and air by-pass valve. Remove heat shields. Disconnect oil hoses and oil pipes from turbocharger. (Scheme 28) Remove coolant hoses, EGR pipe and oxygen sensor.
2. Disconnect exhaust downpipe. Remove bolts securing turbocharger to bracket. Remove turbocharger and exhaust manifold as an assembly. Disassemble turbocharger and exhaust manifold.

Scheme 29

1. Remove exhaust pipe joint. (Scheme 28) Remove coolant pipe (inboard), inlet oil pipe and coolant pipe (outboard). Remove outlet oil pipe. Remove exhaust manifold. For reassembly reference, place turbocharger on a surface plate. (Scheme 29) Mark turbine plate and turbine housing in line with outlet oil pipe.
2. Using ruler, mark wastegate actuator. (Scheme 29) Measure and record distance from surface plate to mark on actuator. Remove wastegate actuator, compressor plate and compressor housing. Remove turbine plates and bearing assembly.

Scheme 30

1. To reassemble, reverse disassembly procedure. Install bearing assembly into turbine housing with outlet oil pipe parallel to mark. (Scheme 29) To prevent heat distortion, install turbine plates as illustrated. (Scheme 30) Install compressor plates with rounded edge toward compressor housing.
2. Remove old sealant from compressor housing (inward of sealing flange) and apply thin bead of NEW sealant. After reassembly, reach into compressor housing through inlet air opening. Rotate turbine wheel. If excessive load or noise exists or if wheel touches housing, replace turbocharger.

1. Add .85 oz. (25 cc) of clean engine oil to oil inlet passage of turbocharger. Install turbocharger with NEW gasket between turbocharger and exhaust manifold.
2. Tighten nuts and bolts to specification. See TORQUE SPECIFICATIONS table at end of article. To complete installation, reverse removal procedure. Prime oil system.

Priming Oil System

Disconnect ignitor electrical connector. Crank engine for 20 seconds. Reconnect ignitor electrical connector. Start engine, and operate it at idle for 30 seconds. Turn engine off. Disconnect negative battery cable. If necessary, depress and hold brake pedal for at least 5 seconds to clear fault code.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS