Engine Controls - Adjustments Mazda Protege BG

ENGINE MECHANICAL

Before performing any on-vehicle adjustments of fuel or ignition systems, ensure engine mechanical condition is okay.

VALVE CLEARANCE

Note. All piston engines are equipped with hydraulic valve lash adjusters. Valve clearance is not adjustable.

RX7

Note. Before adjusting ignition timing, warm engine to normal operating temperature. Turn off all accessories. Place transmission in Neutral (M/T) or Park (A/T). Ensure idle speed is correct. See IDLE SPEED under IDLE SPEED & MIXTURE.

1. Connect a jumper wire between ground and Green test connector near battery. (Scheme 1) Connect timing light to leading spark plug wire (bottom wire) of front rotor housing.
2. If Yellow mark on pulley aligns with indicator pin, go to next step. (Scheme 2) See «IGNITION TIMING SPECIFICATIONS - RX7 TABLE»(/mazda/protege/bg-1989-1994/remont/adjustments/#engine-controls-adjustments). If Yellow mark does not align with indicator pin, loosen Crank Angle Sensor (CAS) lock bolt. Rotate CAS until timing marks are aligned. Tighten lock bolt.
3. Connect timing light to trailing spark plug wire (top wire) of front rotor housing. If Red mark on pulley does not align with indicator pin, loosen CAS lock bolt. Rotate CAS until timing marks are aligned. Tighten lock bolt.

IGNITION TIMING SPECIFICATIONS

Scheme 1

Scheme 2

EXCEPT RX7

Note. Before adjusting ignition timing, warm engine to normal operating temperature. Turn off all accessories. Place transmission in Neutral (M/T) or Park (A/T). Ensure idle speed is correct. See IDLE SPEED under IDLE SPEED & MIXTURE. If timing is not within specification, loosen distributor or Crank Angle Sensor (CAS) lock bolt. Rotate distributor or CAS until timing marks are aligned. Tighten lock bolt.

B2200 & B2600i

On B2200 (PFI) and B2600i, connect jumper wire between ground and Green test connector in right rear corner of engine compartment. (Scheme 4) On all models, connect timing light. Set timing to specification. See IGNITION TIMING SPECIFICATIONS - EXCEPT RX7 TABLE. (Scheme 3) On B2200 (PFI) and B2600i, remove jumper wire.

Note. On Miata, use Blue 1-pin connector near airflow meter as a source of battery power for positive lead of tachometer or timing light (battery is in trunk). DO NOT ground this connector or 20A WIPER fuse will blow.

Scheme 3

Scheme 4

Scheme 5

1. Connect Diagnostic Tester (49B0199A0) to diagnostic connector and select SELF TEST mode, or connect jumper wire between diagnostic connector terminals TEN and GND. (Scheme 5)
2. Connect timing light. Set timing to specification. See «IGNITION TIMING SPECIFICATIONS - EXCEPT RX7 TABLE»(/mazda/protege/bg-1989-1994/remont/adjustments/#engine-controls-adjustments). (Scheme 3) Disconnect diagnostic tester or jumper wire from diagnostic connector.

MPV & 929

Connect jumper wire between ground and Green test connector in left front corner of engine compartment. (Scheme 6), (Scheme 7) and (Scheme 9). Connect timing light. Set timing to specification. See IGNITION TIMING SPECIFICATIONS - EXCEPT RX7 TABLE. (Scheme 3) Remove jumper wire.

Scheme 6

Scheme 7

MX-6 & 626

1. On non-turbo vehicles, disconnect and plug distributor vacuum advance hose. On turbo vehicles, connect jumper wire between ground and Green test connector near left shock tower. (Scheme 8)
2. Connect timing light. Set timing to specification. See «IGNITION TIMING SPECIFICATIONS - EXCEPT RX7 TABLE»(/mazda/protege/bg-1989-1994/remont/adjustments/#engine-controls-adjustments). (Scheme 3) On non- turbo vehicles, connect distributor vacuum advance hose. On turbo vehicles, remove jumper wire.

Scheme 8

Scheme 9

Navajo

1. Engine is equipped with Electronic Distributorless Ignition System (EDIS). Base (initial) timing is preset at 10 degrees BTDC and is not adjustable. To check base timing, turn ignition off.
2. Disconnect Spark Angle Word (SAW) in-line connector in Yellow/Light Green wire near EDIS module, in right front corner of engine compartment. Start engine.
3. Connect timing light and check timing. If ignition timing is not at 10 degrees BTDC, see appropriate TESTS W/O CODES and appropriate G -TEST W/ CODES articles in the ENGINE PERFORMANCE section. Turn off engine. Connect SAW in-line connector.

IGNITION TIMING SPECIFICATIONS

IDLE SPEED & MIXTURE

Note. Mixture adjustment is NOT a normal tune-up procedure. DO NOT adjust mixture unless mixture control unit is replaced or vehicle fails emissions test.

CHOKE (B2200 CARBURETED)

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

COLD (FAST) IDLE SPEED (B2200 CARBURETED)

Note. For adjustments of the choke unloader, fast idle cam (static adjustment) and secondary throttle valve, see appropriate REMOVE/INSTALL/OVERHAUL article in the ENGINE PERFORMANCE section.

1. Warm engine to normal operating temperature. Turn off engine. Disconnect and plug vacuum hoses to idle compensator and reed valves. Hold throttle valve slightly open. Push choke plate fully closed. Release throttle valve.
2. Remove pressure from choke plate. Start engine without touching accelerator pedal or throttle valve. If engine speed is not 3000-4000 RPM, turn fast idle screw until within specification.

DASHPOT

Note. Before adjusting dashpot, warm engine to normal operating temperature. Turn off all accessories. Place transmission in Neutral (M/T) or Park (A/T). On RX7, ensure TPS is adjusted. See THROTTLE POSITION SENSOR (TPS).

B2200 (Carbureted With M/T)

Slowly increase engine RPM until throttle lever separates from dashpot. If engine speed is not 2700-2900 RPM when throttle lever separates from dashpot, loosen lock nut and adjust dashpot as necessary. Tighten lock bolt.

Scheme 10

1. Remove turbocharger intercooler. Disconnect TPS connector. Connect ohmmeter between TPS connector terminals "A" and "B". (Scheme 10)
2. Increase engine RPM until throttle lever separates from dashpot. If resistance is not 1800-3800 ohms when lever separates from dashpot, loosen lock nut and adjust dashpot. Tighten lock bolt.

All Others

Operate engine at 4000 RPM (3500 RPM on RX7 non-turbo). Slowly decrease engine RPM until throttle lever contacts dashpot. If engine RPM is not as specified when throttle lever contacts dashpot, loosen lock nut and adjust dashpot as necessary. See DASHPOT SPECIFICATIONS TABLE. Tighten lock bolt.

DASHPOT SPECIFICATIONS (1)

IDLE SPEED

Note. Before adjusting idle speed, warm engine to normal operating temperature. Turn off all accessories. Place transmission in Neutral (M/T) or Park (A/T). Ensure ignition timing is adjusted. See IGNITION TIMING .

B2200 (Carbureted)

Connect tachometer to negative side of ignition coil primary circuit (White wire). Ensure choke is fully open and throttle valve lever is not resting on fast idle cam. If idle speed is not 825 RPM, turn idle speed adjusting screw on carburetor until within specification.

B2200 (PFI) & B2600i

Connect jumper wire between ground and Green 1-pin test connector in right rear corner of engine compartment. (Scheme 4) Connect tachometer to negative side of ignition coil primary circuit (White wire). If idle speed is not within specification, rotate idle air adjusting screw on throttle body. See IDLE SPEED SPECIFICATIONS TABLE. Disconnect jumper wire.

Note. On Miata, use Blue 1-pin connector near airflow meter as a source of battery power for positive lead of tachometer or timing light (battery is in trunk). DO NOT ground this connector or 20A WIPER fuse will blow.

Miata, Protege & 323

1. Connect Diagnostic Tester (49B0199A0) to diagnostic connector and select SELF TEST mode, or connect jumper wire between diagnostic connector terminals TEN and GND. (Scheme 5) Connect tachometer to diagnostic connector terminal IG(-).
2. If idle speed is not within specification, rotate idle air adjusting screw on throttle body. See IDLE SPEED SPECIFICATIONS TABLE. Disconnect jumper wire.

MPV

1. Connect jumper wire between ground and Green 1-pin test connector in left front corner of engine compartment. (Scheme 6)and (Scheme 7). On 2.6L, connect tachometer to White 1-pin test connector in left front corner of engine compartment. (Scheme 6)
2. On 3.0L, connect tachometer to test connector at ignition coil (White wire). On all models, if idle speed is not within specification, rotate idle air adjusting screw on throttle body. See IDLE SPEED SPECIFICATIONS TABLE. Disconnect jumper wire.

1. Connect jumper wire between ground and Green 1-pin test connector near left shock tower. (Scheme 9) Connect tachometer to White 1-pin test connector near left shock tower.
2. If idle speed is not within specification, rotate idle air adjusting screw on throttle body. See IDLE SPEED SPECIFICATIONS TABLE. Disconnect jumper wire.

Note. On Navajo, idle speed is computer controlled and is not adjustable. However, use the following initial throttle angle adjustment procedure (minimum air rate setting) as a basis for diagnosing idle speed problems or if throttle stop screw has been incorrectly set.

1. Ensure the following conditions exist: throttle bore, throttle plate and Idle Speed Control (ISC) air by-pass valve are free of contamination, oxygen sensor is free of contamination and is operating, throttle stop lever is resting against throttle stop screw, no vacuum leaks are present, cooling system is full and ignition timing is set to specification.
2. Perform a thorough basic inspection and self-test (KOEO, KOER and Continuous Memory self-tests) to confirm operation of sub-systems which may contribute to idle speed control problems. See appropriate G - TEST W/ CODES article in the ENGINE PERFORMANCE section.
3. With engine off, disconnect negative battery cable for at least 5 minutes. Connect negative battery cable. Start engine and allow idle speed to stabilize for 2 minutes. Snap throttle open and return to idle. Lightly press and release accelerator. Turn engine off. Disconnect ISC air by-pass solenoid. NOTE: If engine RPM fluctuates during idle, the throttle plate may be open enough to allow canister purge flow. To verify this condition, disconnect and plug the canister purge line. If purge is present, close the throttle plate until the fluctuations stop.
4. Start engine. Operate engine at 2500 RPM for 30 seconds. Allow engine to idle for 2 minutes. Turn throttle stop screw until engine idles at 675 RPM.
5. Turn off engine. Repeat step 4). Turn off engine. Disconnect negative battery cable for at least 5 minutes. Connect ISC air by-pass solenoid connector. Connect negative battery cable. Verify throttle plate is not stuck in bore and linkage is not preventing throttle stop lever from contacting throttle stop.
6. Start engine and allow to idle for 2 minutes. Snap throttle open and return to idle. Lightly press and release accelerator. Allow engine to idle. If engine does not idle properly, see appropriate TESTS W/O CODES article in the ENGINE PERFORMANCE section.

1. Ensure TPS is adjusted. See THROTTLE POSITION SENSOR (TPS). Connect tachometer to test connector at the trailing coil/igniter assembly. If tachometer does not operate, connect it to the Black 1-pin test connector at leading coil/igniter assembly.
2. If using an inductive pick-up tachometer (secondary ignition), connect it to front or rear trailing spark plug wire. If the pick-up is connected to either of leading spark plug wires, a false reading will result.
3. If idle speed is not within specification, rotate idle air adjusting screw on throttle body. See IDLE SPEED SPECIFICATIONS TABLE. Disconnect jumper wire.

929

1. Connect jumper wire between ground and Green 1-pin test connector in left front corner of engine compartment. (Scheme 7)and (Scheme 9). Connect tachometer to test connector at ignition coil.
2. If idle speed is not within specification, rotate idle air adjusting screw on throttle body. See «IDLE SPEED SPECIFICATIONS TABLE»(/mazda/protege/bg-1989-1994/remont/adjustments/#engine-controls-adjustments). Disconnect jumper wire.

IDLE SPEED SPECIFICATIONS

Scheme 11

Scheme 12

1. Check for presence of mixture screw roll pin. (Scheme 11) If roll pin has already been removed, go to next step. If roll pin is present, remove carburetor. Drive out mixture screw roll pin. Install carburetor.
2. Install air cleaner. Ensure idle compensator valve is closed. Warm engine to normal operating temperature. Connect dwell meter (on 4-cylinder setting) between ground and mixture check connector. (Scheme 12)
3. Adjust idle speed to 825 RPM. Turn mixture adjusting screw until dwell reading is 27-45 degrees. Reset idle speed (if necessary). Replace mixture roll pin after adjustment. If mixture cannot be adjusted to specification, see appropriate TESTS W/O CODES article in the ENGINE PERFORMANCE section.

Except B2200 (Carbureted)

Air/fuel mixture is computer-controlled and cannot be manually adjustment. If CO level is excessive, see TESTS W/O CODES article in the ENGINE PERFORMANCE section.

See B2200 (CARBURETED) under THROTTLE (IDLE) SWITCH.

Scheme 13

1. Warm engine to normal operating temperature. Remove throttle body air inlet hose. Disconnect TPS connector. Install Test Harness (49G018901) between TPS and harness.
2. Turn ignition on. Ensure that throttle valve is fully closed. Using a voltmeter capable of measuring voltage variations of.01 volt, measure voltage at Red and Black wires of test harness. (Scheme 13)
3. If voltage is 4.5-5.5 volt at Red wire, and about zero volt at Black wire, go to next step. If voltages are not as specified, check battery voltage and wiring harness between electronic control unit and TPS. If battery voltage and harness are okay, replace ECU.
4. Record voltage at Red wire. Measure voltage at Blue wire of test harness with the throttle valve at different positions within its entire range. See B2200 PFI, B2600i, MPV 2.6L, MX-6 & 626 TPS VOLTAGE TABLE.
5. If measured voltages do not match voltages specified, loosen TPS screw. Rotate TPS until Blue wire voltage is as specified. Tighten TPS screw. If TPS cannot be adjusted to specification, replace TPS. Disconnect negative battery cable and apply brake pedal for 5 seconds to erase engine control unit memory.
6. If measured voltages increase smoothly and match the voltages specified, turn ignition off. Disconnect test harness. Reconnect TPS connector. Disconnect negative battery cable and apply brake pedal for 5 seconds to erase engine control unit memory.

B2200 PFI, B2600i, MPV 2.6L, MX-6 & 626 TPS VOLTAGE

Scheme 14

1. Disconnect TPS connector. Connect an ohmmeter between TPS connector terminals "E" and IDL. (Scheme 14) Insert feeler gauge of specified thickness between throttle lever and throttle stop screw. See «MIATA, PROTEGE & 323 WITH A/T TPS CONTINUITY TEST TABLE»(/mazda/protege/bg-1989-1994/remont/adjustments/#engine-controls-adjustments).
2. If continuity is not as specified, adjust TPS. See ADJUSTMENT. If continuity is as specified, connect ohmmeter between TPS connector terminals Vt and "E". If resistance is less than 1000 ohms with throttle fully closed and about 5000 ohms with throttle wide open, TPS is adjusted. If resistance is not as specified, adjust TPS. See ADJUSTMENT.

Note. If ohmmeter reading indicates a rough transition anywhere in range between lowest and highest readings, TPS potentiometer is faulty. Replace TPS.

1. Disconnect TPS connector. Connect ohmmeter between TPS connector terminals "E" and IDL. (Scheme 14) Loosen TPS attaching screws.
2. Insert a.010" (.25 mm) feeler gauge between throttle lever and throttle stop screw. Rotate TPS clockwise about 30 degrees, then rotate counterclockwise until ohmmeter indicates continuity.
3. Remove feeler gauge. Insert a.016" (.40 mm) feeler gauge between throttle lever and throttle stop screw. If ohmmeter indicates no continuity, go to next step. If ohmmeter indicates continuity, repeat adjustment procedure.
4. Tighten TPS attaching screws. Open throttle valve fully and verify resistance between terminals "E" and Vt is about 5000 ohms.

MIATA, PROTEGE & 323 WITH A/T TPS CONTINUITY TEST

Inspection

1. Disconnect TPS connector. Insert feeler gauge of specified thickness between throttle lever and throttle stop screw. See «MIATA, PROTEGE & 323 WITH M/T TPS CONTINUITY TEST»(/mazda/protege/bg-1989-1994/remont/adjustments/#engine-controls-adjustments) table.
2. Connect ohmmeter between specified terminals of TPS connector. (Scheme 15) If continuity is not as specified, adjust TPS. See ADJUSTMENT.

Scheme 15

1. Disconnect TPS connector. Connect ohmmeter between terminals IDL and TL of TPS connector. (Scheme 15) Insert a.016" (.41 mm) feeler gauge between throttle lever and throttle stop screw.
2. Loosen TPS screws. Rotate TPS clockwise about 30 degrees, then rotate counterclockwise until ohmmeter indicates continuity.
3. Remove feeler gauge. Insert a.027" (.69 mm) feeler gauge between throttle lever and throttle stop screw. If ohmmeter indicates no continuity, go to next step. If ohmmeter indicates continuity, repeat adjustment procedure.
4. Tighten TPS attaching screws. Open throttle valve fully a few times. Recheck TPS adjustment.

MIATA, PROTEGE & 323 W/ M/T TPS CONTINUITY TEST

Disconnect TPS connector. Using an ohmmeter, measure resistance between specified terminals of TPS connector. (Scheme 16)and (Scheme 17). If resistance is not as specified in MPV 3.0L & 929 TPS RESISTANCE TABLE, adjust TPS. See ADJUSTMENT.

Scheme 16

Scheme 17

1. Insert a feeler gauge of specified thickness between throttle lever and throttle stop screw. Check continuity between TPS connector terminals "C" and "D". (Scheme 16)and (Scheme 17).
2. If continuity is not as specified in «MPV 3.0L & 929 TPS ADJUSTMENT TABLE»(/mazda/protege/bg-1989-1994/remont/adjustments/#engine-controls-adjustments), loosen TPS mounting screws. Rotate TPS until continuity is as specified. Tighten mounting screws. Connect TPS connector.

MPV 3.0L & 929 TPS RESISTANCE

MPV 3.0L & 929 TPS ADJUSTMENT

Note. On Navajo, TPS is not adjustable. Replace TPS if voltage readings are not within specification.

1. Ensure throttle linkage is not preventing throttle stop lever from contacting throttle stop screw. Disconnect Electronic Control Assembly (ECA) 60-pin connector. Inspect connector for damaged pins, corrosion or loose wires and repair as necessary.
2. Connect Breakout Box (T83L-50-EEC-IV) between ECA and ECA harness. Connect digital voltmeter positive lead to pin No. 47 and negative lead to pin No. 46 of breakout box.
3. Turn ignition on. Observe voltmeter reading while slowly moving throttle between fully closed and wide open positions. If voltage is .34 with throttle fully closed and 4.84 with throttle fully open, TPS voltages are within specification.
4. If voltages are not within specification, ensure throttle angle (minimum air rate) is correct. See IDLE SPEED under IDLE SPEED & MIXTURE. If throttle angle is correct, remove TPS.
5. Check for damaged, corroded or misadjusted pins. If pins are okay, install TPS, ensuring it is correctly seated. Check voltage readings again. If voltage readings are not as specified, perform KOEO self-test. See appropriate G - TEST W/ CODES article in the ENGINE PERFORMANCE section. If KOEO self-test indicates no problems, replace TPS.

1. Warm engine to normal operating temperature. Turn off engine. Connect Engine Signal Monitor (499200162) between ECU and ECU wire harness using Adapter Harness (49G018903).
2. Check voltages at ECU terminals 2F and 2G. (Scheme 18) See «RX7 TPS VOLTAGE TABLE»(/mazda/protege/bg-1989-1994/remont/adjustments/#engine-controls-adjustments). If voltages are not within specification, remove engine signal monitor and adapter harness. Adjust TPS. See ADJUSTMENT.

Scheme 18

Scheme 19

1. Warm engine to normal operating temperature. Turn off engine. Connect Checker Light (49F018001) to Green 3-pin test connector. (Scheme 19) Turn ignition on.
2. If one of the lights comes on, TPS is adjusted. If both or neither lights come on, turn the TPS adjusting screw until only one of the lights comes on. (Scheme 20) Replace TPS if it cannot be adjusted.

TPS VOLTAGE

Scheme 20

Scheme 21

1. Warm engine to operating temperature. Connect tachometer. Operate engine at idle. Using voltmeter, backprobe Light Green/Red wire terminal of idle switch connector. (Scheme 21)
2. Increase engine speed to more than 2000 RPM. Gradually decrease engine speed. If voltage is not as specified in «B2200 CARBURETED THROTTLE SWITCH VOLTAGE TEST TABLE»(/mazda/protege/bg-1989-1994/remont/adjustments/#engine-controls-adjustments), turn idle switch adjusting screw until voltage is within specification.

B2200 CARBURETED THROTTLE SWITCH VOLTAGE TEST

Throttle switch is part of the throttle position sensor (adjusted automatically when TPS is adjusted) or is a separate, nonadjustable switch on the throttle body. See THROTTLE POSITION SENSOR (TPS).

See also:
• IGNITION TIMING SPECIFICATIONS - RX7 TABLE