Remove/install/overhaul Mazda 323 BF

INTRODUCTION

Removal, overhaul and installation procedures (when given by manufacturer) are covered in this article. If component removal and installation is primarily an unbolt and bolt on procedure, a simple torque specification may be all that is furnished.

Scheme 1

Scheme 2

1. Remove dashpot vacuum hose. Remove accelerator pump connecting rod, spring and lever. Disconnect air vent solenoid valve lead from connector. Disconnect choke rod. Remove air horn retaining bolts.
2. Remove air horn and choke assembly from main body. Remove air vent solenoid valve, spring and gasket from air horn. Remove float, pin and gasket. Remove needle valve. Remove sight glass assembly from main body. CAUTION: Note location and size of jets and air bleeds prior to removal. Components must be installed in correct location.
3. Remove secondary slow jet, secondary slow bleed, secondary main bleed, and secondary main jet from main body. Remove primary main bleed, slow jet and plug, primary slow bleed and primary main jet from main body. (Scheme 1), (Scheme 2) and (Scheme 3).
4. Remove richer air bleed, primary slow bleed, coasting richer air bleed and coasting richer jet from air horn. (Scheme 2) Remove coasting richer solenoid valve and "O" ring from main body.
5. Remove idle switch and spring. Remove slow fuel-cut solenoid valve, spring and gasket. Remove dashpot. Remove accelerator pump plunger and spring. Remove strainer and inlet check ball.
6. Remove plug and outlet check ball and spring. Disconnect throttle link. Disconnect vacuum diaphragm connecting rod. Disconnect throttle return spring.
7. Remove throttle body retaining bolts. One bolt is located inside throttle body. Separate throttle body from main body.
8. Remove vacuum 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.
9. Remove mixture adjusting screw. Do not remove throttle valve and shaft, or choke valve and shaft from housings.

Note. Do not immerse diaphragm, electrical components, or synthetic parts in carburetor cleaner.

Scheme 3

CLEANING & INSPECTION

1. Thoroughly clean parts in carburetor cleaner. Dry components with compressed air. Blow out all passages with compressed air. Do not use wire or pointed metal objects for cleaning. Inspect air horn, main body and throttle body for cracks and breakage.
2. Inspect choke and throttle shafts 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 or burrs. Apply battery voltage to solenoids and note valve stem movement. Stem movement should exist.
4. Check choke thermostat cover by connecting an ohmmeter to wire coupler and heater ground. If there is no continuity, replace thermostat cover.
5. Check A/F solenoid valve operation by connecting battery voltage to solenoid connector. Check that air will flow through A/F solenoid in direction indicated with battery voltage applied. (Scheme 4) The A/F solenoid is not serviceable. Air horn assembly must be replaced if A/F solenoid is defective.

Scheme 4

REASSEMBLY

1. To reassemble, reverse disassembly procedure using new gaskets. The "O" ring located on A/F solenoid valve must be replaced and coated with gasoline prior to installation.
2. Check float level and float drop adjustment prior to installing air horn. Perform all adjustments after assembly. See «ADJUSTMENTS»(/mazda/323/bf-1985-1993/remont/removal-installation/#removeinstalloverhaul__adjustments) in this article. Do not install spring pin in front of mixture screw until adjustment has been made with engine running.

ADJUSTMENTS

Note. For all on-vehicle adjustments not covered in this article, see ADJUSTMENTS article.

Float Level

1. With engine running, check fuel level in fuel bowl sight glass. If fuel level is not to specified mark on sight glass, remove carburetor from vehicle.
2. Remove air horn from carburetor. Remove gasket from air horn. Invert carburetor and allow float to hang by its own weight. Measure clearance between top of float and air horn. (Scheme 5)
3. Float clearance must be within specification. See «CARBURETOR ADJUSTMENT SPECIFICATIONS»(/mazda/323/bf-1985-1993/remont/removal-installation/#removeinstalloverhaul) table. Bend float seat for adjustment.

Scheme 5

Float Drop

Position air horn upright. Allow float to hang by its own weight. Measure clearance between bottom of float and air horn. Float drop must be within specification. Bend float stop for adjustment. (Scheme 6) See CARBURETOR ADJUSTMENT SPECIFICATIONS table.

Scheme 6

Choke Linkage (Fast Idle Opening Angle)

1. Fully close choke valve. Position fast idle cam on second highest step. Measure clearance between primary throttle valve and throttle bore wall. (Scheme 7)
2. Clearance should be within specification. Clearance is adjusted by rotating fast idle adjusting screw. See «CARBURETOR ADJUSTMENT SPECIFICATIONS»(/mazda/323/bf-1985-1993/remont/removal-installation/#removeinstalloverhaul) table.

Scheme 7

Choke Valve Opening

Ensure choke linkage adjustment is correct. Place fast idle cam on second highest position. Measure clearance between choke valve and air horn. (Scheme 8) Adjust clearance to specification by bending starting arm. If large adjustment is required, bend choke rod.

Scheme 8

Choke Diaphragm

1. Using vacuum pump, apply approximately 16 in. Hg to choke diaphragm. Lightly close choke valve. Measure clearance between choke valve and air horn. (Scheme 9)
2. Clearance must be within.067-.085" (1.70-2.16 mm). Adjust clearance by bending tang on choke lever.

Scheme 9

Choke Unloader

Close choke valve. Fully open primary throttle valve. Measure clearance between air horn and choke valve. Adjust clearance to.110-.143" (2.80-3.62 mm) by bending tab. (Scheme 10).

Scheme 10

Secondary Throttle Valve

1. Secondary throttle valve should start to open when primary throttle valve opens 50-54 degrees. Measure clearance between primary throttle valve and bore when secondary throttle valve starts to open. (Scheme 11)
2. Clearance should be within.289-.325" (7.35-8.25 mm). Adjust clearance by bending tab.

Scheme 11

Accelerator Linkage

1. Accelerator pedal cable free play at carburetor should be .04-.12" (1.0-3.0 mm). Cable free play can be adjusted by use of cable adjusting nut.
2. Adjust cable free play. Fully depress accelerator pedal. Note that throttle valves fully open. Accelerator stop bolt can be adjusted to obtain full valve opening.

CARBURETOR ADJUSTMENT SPECIFICATIONS

Scheme 12

Scheme 13

Scheme 14

Scheme 15

Scheme 16

Scheme 17

3.0L ENGINE

Note. Constant fuel pressure is maintained in fuel lines and component parts at all times. Relieve pressure before attempting to open system for component removal. DO NOT allow fuel to flow onto engine or electrical parts or allow an open flame in area while testing fuel system components.

Scheme 18

1. To release fuel pressure, apply parking brake and block rear wheels. On 929 models, start engine and disconnect fuel pump relay. (Scheme 18) On MPV models, start engine and disconnect airflow meter connector. On all models, allow engine to stall. Turn ignition off and reconnect relay or connector.
2. Disconnect negative battery cable. Remove fresh air duct, air cleaner and air intake tube. Disconnect accelerator cable. Remove canister and power brake vacuum hoses.
3. Remove fuel hoses from pressure regulator, making sure to cover hose fitting with rag to prevent possible fuel spray. Plug disconnected hoses to prevent fuel leakage.
4. Remove automatic transmission vacuum hose (if equipped). Drain about 2 quarts of coolant. Disconnect coolant hoses from throttle body. Remove throttle body. Remove BAC valve. Remove intake air pipe.
5. Remove extension manifolds between dynamic chamber and intake manifold. Remove dynamic chamber. Remove fuel rails and fuel injectors.

Installation

To install, reverse removal procedure using new gaskets. Tighten all mounting bolts to 20 ft. lbs. (25 N.m).

Scheme 19

ALL OTHER ENGINES

Removal and installation is primarily an unbolt and bolt on procedure. Mark all components for reinstallation before removing. To release fuel pressure, see BASIC TESTING article.

REMOVAL & INSTALLATION (B2200 - MECHANICAL)

Remove outlet, inlet and return hoses. Remove fuel pump, insulator and gasket. To install, reverse removal procedure.

REMOVAL & INSTALLATION (B2200 - ELECTRIC)

Remove fuel tank. Remove fuel gauge/pump assembly from tank. Remove wires. Remove fuel pump from bracket. Remove hose. To install, reverse removal procedure.

REMOVAL (B2600I)

Remove inlet and outlet hoses. Remove electrical connector. Remove fuel tank. Remove fuel sender/pump assembly.

Install fuel pump terminals. (Scheme 20) Tighten positive terminal to 10-17 INCH Lbs. (1.2-2.0 N.m). Tighten negative terminal to 20-29 INCH Lbs. (2.3-3.4 N.m). Using new fuel hose, install clamps. (Scheme 20) Install pump into bracket assembly. Remainder of installation is reverse of removal.

Scheme 20

REMOVAL & INSTALLATION (MPV, MX-6, PROTEGE, 323, 626 & 929)

On 626 and MX-6, remove rear seat. On 323, remove seat cushion. On MPV 2.6L, remove No. 2 rear seat. On all models, lift floor mat. Remove fuel pump access cover. Remove hoses and electrical connector. Remove fuel pump/sender assembly. To install, reverse removal procedure using new rubber seal and hoses.

REMOVAL & INSTALLATION (ALL OTHERS)

Lift rear floor mat. On Miata, remove rear package trim. On all models, remove access cover. Remove hoses and electrical connector. Remove fuel pump/sender assembly. To install, reverse removal procedure.

REMOVAL & INSTALLATION

If exhaust sensor is difficult to remove, use rust penetrant to avoid possible damage to exhaust threads. Apply anti-seize to sensor threads (if reusing old sensor). New sensor comes precoated with anti-seize. DO NOT remove anti-seize from sensor.

Removal (MX-6 & 626)

1. Drain engine coolant. Remove air hoses and air by-pass valve. Remove turbocharger heat insulators. Remove oil pipes from turbocharger. Remove coolant hoses, EGR pipe and oxygen sensor.
2. Loosen bolts securing turbocharger to bracket. Remove nuts attaching exhaust pipe to turbocharger. Remove nuts attaching turbocharger to exhaust manifold. Remove turbocharger.

Scheme 21

Removal (323)

1. Remove engine undercover. Drain engine coolant. Remove radiator. Remove intake air pipe and intake air hoses.
2. Remove turbocharger heat insulators. Remove coolant hoses from turbocharger. Remove oil pipes from turbocharger.
3. Loosen bolts securing turbocharger to bracket. Remove nuts attaching exhaust pipe to turbocharger. Remove nuts attaching turbocharger to exhaust manifold. Remove turbocharger.

Scheme 22

Installation (All Models)

To install, reverse removal procedure. Replace gasket between turbocharger and exhaust manifold. Before installation, add 25 cc of clean engine oil to oil passage of turbocharger.

See also:
• ADJUSTMENTS
• CARBURETOR ADJUSTMENT SPECIFICATIONS