Adjustments - 4-cyl Mazda MPV V

ENGINE COMPRESSION

1. Ensure battery is fully charged and engine is at normal operating temperature. Allow engine to cool for 10 minutes. Remove spark plugs and disconnect ignition coil primary connector.
2. Remove spark plugs and fully open throttle valve. Attach compression gauge and crank engine until maximum pressure is reached at each cylinder. Lowest cylinder pressure should be at least 75% that of the highest cylinder pressure.

VALVE CLEARANCE

All piston engines have Hydraulic Lash Adjusters (HLA) and do not require adjustment.

4-Cylinder Ignition Timing

1. With engine at normal operating temperature, place manual transmission in "Neutral" or automatic transmission in "Park". Disconnect and plug vacuum advance hoses (if equipped).
2. On all except B2200, connect a jumper wire between Green test connector and ground. On B2200, disconnect distributor vacuum advance hose. On all models, be sure idle speed is set to specifications. Connect timing light and set timing as required.

4-CYLINDER IGNITION TIMING

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Scheme 5

Scheme 6

IDLE SPEED & MIXTURE

Note. Mixture adjustment is NOT a part of normal tune-up procedure and should not be performed unless mixture control unit is replaced or vehicle fails emissions testing.

Fast Idle Cam

Adjust fast idle cam by measuring clearance between primary throttle valve and wall of the throttle bore with throttle set on the second step of fast idle cam. Clearance should be .033-.041" (.84-1.4mm). Rotate adjustment screw to obtain correct clearance (if necessary).

CHOKE & THROTTLE VALVE ADJUSTMENT

Choke Valve

Adjust choke valve by measuring clearance between valve and wall of the throttle bore with choke valve closed. Clearance should be .024-.045" (.60-1.14 mm). If small adjustment is necessary, bend choke rod lever. If large adjustment is required, bend choke rod linkage.

Secondary Throttle Valve

Remove carburetor. Adjust secondary throttle valve by measuring clearance between primary throttle valve and wall of the throttle bore when secondary throttle starts to open. Clearance should be .289-.325 (7.35-8.25 mm). If adjustment is necessary, bend throttle lever tab.

4-CYLINDER IDLE SPEED

Switch off all accessories. Set parking brake and block drive wheels. Connect tachometer to engine. Warm engine to normal operating temperature. Ensure ignition timing is correct.

B2200

Idle is adjusted by rotating adjustment screw located on carburetor.

B2600i, MPV (4-Cyl.), & 323

Attach Green test connector to ground. (Scheme 4), (Scheme 5) or (Scheme 6). If idle RPM is not within specification, adjust air adjusting screw located on throttle body next to throttle lever.

MX-6 & 626

Operate engine at 2500-3000 RPM for 3 minutes. Connect a jumper wire between Green test connector and ground. (Scheme 3) If RPM is not within specification, remove idle adjustment plug from throttle body and adjust idle to specification.

IDLE SPEED SPECIFICATIONS

Dashpot Adjustment

Warm engine to normal operating temperature and attach tachometer. Operate throttle lever while observing dashpot rod. Rod should contact throttle lever at specified RPM. See DASHPOT ADJUSTMENT table. If necessary, loosen dashpot locknut and adjust dashpot to correct position.

DASHPOT ADJUSTMENT

Scheme 7

1. Remove carburetor from engine. Drive out mixture screw roll pin. (Scheme 7) Install carburetor on engine. Install air cleaner and connect hoses to idle compensator, thermosensor and reed valves.
2. Warm engine to normal operating temperature. Attach dwell meter (4-cyl. setting) to mixture check connector. (Scheme 8)
3. Adjust idle speed to specification. See «IDLE SPEED SPECIFICATIONS»(/mazda/mpv/v-1986-1991/remont/adjustments/#adjustments-4-cyl) table. Turn mixture adjusting screw to obtain a dwell reading of 27-45 degrees. Reset idle speed if necessary. Replace mixture roll pin after adjustment. If dwell reading cannot be obtained, see BASIC TESTING and SYSTEM/COMPONENT TESTS articles.

Scheme 8

4-CYL. (FUEL INJECTED)

Air/fuel mixture is controlled by the computer and there is no provision for manual adjustment. If CO level is excessive, an examination of the entire system should be performed. See the appropriate section of BASIC TESTING .

THROTTLE POSITION SENSOR (TPS)

Note. All procedures are made with engine at normal operating temperature.

323 Non-Turbo

1. Disconnect TPS connector. Using an ohmmeter, check continuity with selected thickness gauge between throttle stop screw and stop lever. See «TPS ADJUSTMENT TABLE - 323 NON-TURBO»(/mazda/mpv/v-1986-1991/remont/adjustments/#adjustments-4-cyl).
2. To adjust, loosen TPS attaching screws. Connect ohmmeter between terminals IDL and TL. (Scheme 9) Insert a.020" (.5 mm) thickness gauge between adjustment screw and stop lever. Rotate TPS until ohmmeter shows continuity.
3. Insert a.028" (.7 mm) thickness gauge between adjustment screw and stop lever. Ohmmeter should show no continuity. If ohmmeter does not read correctly, repeat adjustment procedure to obtain correct readings.

TPS ADJUSTMENT

Scheme 9

Scheme 10

1. To check TPS voltage, remove rubber boot from connector. Turn ignition on. Check voltage between each terminal and ground. Open throttle valve and check voltage between each terminal and ground once more. (Scheme 10) See «TPS VOLTAGE TABLE - 323 TURBO»(/mazda/mpv/v-1986-1991/remont/adjustments/#adjustments-4-cyl).
2. If voltage reading is incorrect at terminal "D" only, check TPS setting and adjust if necessary. If voltage reading is incorrect at any other terminal, check resistance of TPS, connections at terminals "1G", "2A", "2C" and "2E" of ECU and wiring harness, go to step 5).
3. To check resistance of TPS, measure resistance between terminals with TPS connector disconnected. See «TPS RESISTANCE TABLE - 323 TURBO»(/mazda/mpv/v-1986-1991/remont/adjustments/#adjustments-4-cyl). If resistance readings are incorrect, replace sensor.
4. To adjust TPS, disconnect connector from TPS. Connect an ohmmeter between terminals "B" and "D". Insert a.020" (.5 mm) thickness gauge between adjustment screw and stop lever. Ohmmeter should show continuity.
5. Insert a.028" (.7 mm) thickness gauge between adjustment screw and stop lever. Ohmmeter should show no continuity. If ohmmeter does not read correctly, adjust TPS to obtain correct readings in steps 4) and 5).

TPS VOLTAGE

TPS RESISTANCE

B2600i, MPV (4-CYL.), MX-6 & 626

1. Remove throttle body air hose. Install test harness (49 G018 901) between TPS and harness. Turn ignition on. With throttle closed, measure TPS connector voltage at Red and Black wires.
2. Red wire should have 4.5-5.5 volts. Black wire should have zero volts. If voltage is incorrect, check battery voltage, wiring harness and connectors. If okay, see TESTS W/CODES and SYSTEM/COMPONENT TESTS articles.
3. If voltage in step 2) was okay, measure voltage at Blue wire while slowly opening and closing throttle valve. See B2600i, MPV (4-CYL.), MX-6 & 626 TPS VOLTAGE table.
4. If voltage is not to specification, loosen TPS and rotate sensor until Blue wire voltage is correct. If TPS cannot be adjusted to specifications, replace TPS unit. When procedure is completed, remove negative battery cable and apply brake pedal for 5 seconds to erase control unit memory.

TPS VOLTAGE

Scheme 11

See also:
• IDLE SPEED SPECIFICATIONS