Engine Controls - Basic Diagnostic Procedures: Other Mazda Tribute I

Compression

Check engine mechanical condition with a compression gauge, vacuum gauge, or an engine analyzer. Ensure oil level and condition are okay. Ensure battery is fully charged. See engine analyzer manual for specific instructions.

COMPRESSION SPECIFICATIONS

Exhaust System Backpressure

Exhaust system can be checked with a vacuum or pressure gauge. Remove Heated Oxygen Sensor (HO2S) or air injection check valve (if equipped). Connect a 0-5 psi pressure gauge and run engine at 2500 RPM. If exhaust system backpressure is greater than 2 psi, exhaust system or catalytic converter is plugged.

If a vacuum gauge is used, connect vacuum gauge hose to intake manifold vacuum port and start engine. Observe vacuum gauge. Open throttle part way and hold steady. If vacuum gauge reading slowly drops after stabilizing, exhaust system should be checked for a restriction.

PRELIMINARY CHECKS

Ensure following systems and components are in good condition and operating properly before diagnosing problems in fuel injection system

1. Battery and charging system condition.
2. All wiring and vacuum connections.
3. Air cleaner and ducting.
4. State of tune.
5. Fuel delivery system.
6. Cooling system.
7. Inertia fuel shutoff switch.
8. Hydrolocked cylinder(s) (liquid in cylinder).
9. Fuel tank contents and fuel gauge accuracy.
10. Dirt, water or other contamination in fuel.
11. Fuel lines and fittings for leaks.
12. Fuel delivery system for proper pressure and volume.
13. Inoperative fuel injectors.
14. Improperly installed electronic equipment such as anti-theft system, CB radio, cellular telephone or stereo.

Engine Does Not Crank

1. Check for enabled anti-theft system.
2. Check for hydrolocked engine (liquid in cylinder).
3. Check starting and charging system for correct operation.
4. Check Transmission Range (TR) switch adjustment and operation.
5. Locked up flywheel or flexplate.

Repair as necessary.

Engine Cranks But Will Not Start

1. Check fuel tank contents and fuel gauge accuracy. Check for dirt, water or contamination in fuel.
2. Check fuel lines and fittings for leaks. If no leaks are found, check fuel delivery system for proper pressure and volumes. Reset Inertia Fuel Shutoff (IFS) switch (if necessary).
3. Check for damaged or contaminated fuel injector wiring harness and connector. Ensure fuel injectors pulse when engine is cranked.
4. Check ignition system for strong spark at spark plugs. If spark is not present or if spark is weak, proceed as follows: On all EEC-V models, go to TEST JE in appropriate SELF-DIAGNOSTICS article. On all others, go to appropriate SELF-DIAGNOSTICS article.
5. Check engine compression.
6. Check valve timing.
7. Check for overheating engine.
8. Check for intake air system leak.
9. Check operation of Idle Air Control (IAC) valve.
10. Check for damaged or faulty crankshaft pulley and Crankshaft Position (CKP) sensor.

Repair as necessary.

Except B2300, B3000, B4000 & Tribute 3.0L

Remove fuel filler cap, to release fuel tank pressure. Disconnect fuel pump relay. See FUEL PUMP RELAY LOCATIONS table. Start engine (if possible) and allow to die. Crank engine several times. Turn ignition switch off. Reconnect fuel pump relay.

FUEL PUMP RELAY LOCATIONS

Fuel Pump Resistor & Relay (Millenia 2.3L)

1. Fuel pump resistor and relay (speed) is located in left front corner of engine compartment. (Scheme 8) Disconnect fuel pump resistor and relay connector. To check fuel pump resistor, measure resistance between relay terminals "A" and "B". (Scheme 9) Resistance should be.38-.42 ohms. If resistance is not as specified, replace fuel pump resistor and relay (speed).
2. To check relay, check for continuity between terminals "E" and "F". (Scheme 9) Continuity should not be present. Using fused jumper wires, connect positive battery terminal to connector terminal "C" and ground terminal "D". Continuity should be present between terminals "E" and "F". If continuity is not as specified, replace fuel pump resistor and relay (speed).

Scheme 8

Scheme 9

IGNITION CHECKS

Note. Perform following tests in sequence shown, unless test procedures indicate otherwise. For the following test, the term Electronic Ignition (EI) may be used to describe the ignition system.

Spark Check

Remove spark plug. Connect spark plug to high-tension lead and hold about 1/4" from ground. Crank engine and verify a strong Blue spark is discharged. If spark is not present, measure spark plug wire resistance on suspect wire. Resistance should be less than 16,000 ohms per 3.28 feet. Replace spark plug wire and spark plug as necessary.

Camshaft Position Sensor (Miata)

Note. May require removal of PCM to gain access to wire terminals.

Scheme 10

Scheme 11

1. Remove and inspect Camshaft Position (CMP) sensor. Clean off any metal particles or shavings. Reinstall sensor.
2. Connect scan tool to DLC-2. Start engine. Using scan tool, enter vehicle information. Connect oscilloscope positive test lead to PCM 24-pin harness connector terminal "3V" (Gray/Blue wire) and negative test lead to 31-pin harness connector terminal "4A" (White/Red wire). (Scheme 10) Select DIGITAL MEASUREMENT SYSTEM, then FREQUENCY METER. Press link key to select RPM PID. Select PID/DATA MONITOR, then PCM. Press START.
3. Set oscilloscope to 2.0V/DIV (Y), 20ms/DIV (X), DC range. Inspect wave profile with engine idling. (Scheme 11) If wave profile or voltage are not as specified, check for short or open circuit between: CMP sensor 3-pin harness connector terminal "B" and PCM 24-pin harness connector terminal "3V" (Gray/Blue wire). CMP sensor 3-pin harness connector terminal "A" and main relay 4-pin harness connector terminal "D" through common connector (White/Red wire). CMP sensor terminal "C" and PCM 31-pin harness connector terminal "4A" (Black/Blue wire). If open or short circuit are found repair or replace wiring harness as necessary. If short or open circuit are not found, replace CMP sensor. Check protrusion on intake camshaft for damage and cracks. Repair as necessary.

CMP/PCM TERMINAL IDENTIFICATION (PROTEGE)

Camshaft Position Sensor (Millenia 2.3L)

Camshaft Position (CMP) sensor is located on right front of engine. Disconnect CMP sensor harness connector. Check for continuity between CMP sensor connector terminals "B" (Red/Black wire) and "C" (Yellow/Black wire). If continuity is present, replace CMP sensor. If continuity is not present, check for short or open circuit between following

1. CMP sensor 4-pin harness connector terminal "B" and main relay 4-pin harness connector terminal "D" (Red/Black wire).
2. CMP sensor 4-pin harness connector terminal "C" and PCM 34-pin harness connector terminal "4F" (Yellow/Black wire).
3. CMP sensor 4-pin harness connector terminal "A" and PCM 34-pin harness connector terminal "4D" (Black/Blue wire).

Repair open or short circuit in wiring harness as necessary.

Camshaft Position Sensor (Millenia 2.5L)

Camshaft Position (CMP) sensor is located inside of distributor and is an integrated part. Disconnect distributor 6-pin harness connector. Check for continuity between distributor connector terminals "B" and "D". If continuity is not present, check for open or short between

1. Distributor 6-pin harness connector terminal "B", PCM 34-pin harness connector terminals "4A" and "4C" and main relay terminal "D" (Red/Black wire).
2. Distributor 6-pin harness connector terminal "D", PCM 34-pin harness connector terminals "4F" (Pink/Black wire).

Repair wiring harness as necessary. If wiring is okay, replace distributor.

Scheme 12

1. Disconnect Camshaft Position (CMP) sensor connector. (Scheme 12) Measure resistance between CMP sensor connector terminals. If resistance is 308-376 ohms, go to next step. If resistance is not as specified, replace CMP sensor.
2. If resistance reading is okay but PID value or voltage is out of specification, check for open or short circuit in wiring harness. Disconnect PCM harness connector. Connect 104-pin breakout box to PCM harness connector. (Scheme 14) Leave PCM disconnected. Check continuity of following circuits: Between CMP sensor harness connector terminal "A" (Brown/Light Green wire) and PCM harness connector terminal No. 85 (Orange wire). (Scheme 13) Between CMP sensor harness connector terminal "B" (Blue/Orange wire) and PCM harness connector terminal No. 86 (Yellow wire). If continuity is not present, repair open circuit in wiring harness. If continuity is present, check for short circuit between following: Between CMP sensor harness connector terminal "A" (Brown/Light Green wire) and power. Between CMP sensor harness connector terminal "A" (Brown/Light Green wire) and ground. Between CMP sensor harness connector terminal "B" (Blue/Orange wire) and power. Between CMP sensor harness connector terminal "B" (Blue/Orange wire) and ground. If continuity is present, repair or replace wiring harness as necessary.

Scheme 13

Scheme 14

Camshaft Position Sensor (Protege & Protege5)

1. Disconnect Camshaft Position (CMP) sensor connector. CMP sensor is located near front of valve cover. Using ohmmeter, measure resistance between CMP sensor connector terminals. Resistance should be 950-1250 ohms. If resistance reading is not as specified, replace CMP sensor.
2. If sensor is okay, disconnect PCM harness connector and install 104-pin breakout box. (Scheme 14) Check for open or short in following circuits: Between CMP sensor harness connector terminal "A" and PCM harness connector terminal No. 85 (Blue wire). Between CMP sensor harness connector terminal "B" and PCM harness connector terminal No. 86 (Green wire). Repair or replace wiring harness as necessary.

Camshaft Position Sensor (626 2.0L)

Disconnect Camshaft Position (CMP) sensor harness connector. CMP sensor connector is located on timing belt cover, at upper front of engine. Using ohmmeter, measure resistance between CMP sensor terminals. Resistance should be 950-1250 ohms. If resistance reading is not as specified, replace CMP sensor. If CMP sensor is okay, disconnect PCM harness connector and check for open or short circuit in wiring harness between following

1. CMP sensor terminal and PCM harness connector terminal No. 87 (Blue wire).
2. CMP sensor terminal and PCM harness connector terminal No. 85 (Pink wire).

Repair or replace wiring harness as necessary.

Camshaft Position Sensor (626 2.5L)

Disconnect Camshaft Position (CMP) sensor harness connector. CMP sensor is located next to right timing pulley. Using ohmmeter, measure resistance between CMP sensor harness connector terminals "A" and "B". Resistance should be approximately 550 ohms. If resistance reading is not as specified, replace CMP sensor. If CMP sensor is okay, disconnect PCM harness connector and check for open or short circuit in wiring harness between following

1. CMP sensor terminal and PCM harness connector terminal No. 8 (Blue wire).
2. CMP sensor terminal and PCM harness connector terminal No. 85 (Pink wire).

Repair or replace wiring harness as necessary.

Crankshaft Position Sensor Resistance (Except Miata)

Note. Miata CKP sensor resistance testing not available from manufacturer.

Disconnect Crankshaft Position (CKP) sensor connector. Using ohmmeter, measure resistance between terminals "A" and "B". (Scheme 15) Resistance should be as specified. See CRANKSHAFT POSITION SENSOR RESISTANCE table. If resistance is not as specified, replace crankshaft position sensor.

CRANKSHAFT POSITION SENSOR RESISTANCE

Scheme 15

Crankshaft Position Sensor Air Gap (Except MPV)

Note. MPV air gap inspection and specification not available from manufacturer.

Using a feeler gauge, measure air gap between crankshaft pulley and Crankshaft Position (CKP) sensor. (Scheme 16)- (Scheme 20). If air gap is not.020-.060" (.5-1.5 mm), replace crankshaft pulley or CKP sensor. On Miata, CKP sensor is adjustable. If sensor will not adjust, replace CKP sensor or plate behind crankshaft pulley.

Scheme 16

Scheme 17

Scheme 18

Scheme 19

Scheme 20

Ignition Coil Resistance (Miata, Protege & Protege5)

Using an ohmmeter, measure secondary resistance between coil towers No. 1 and 4 and between coil towers No. 2 and 3. (Scheme 22) Resistance should be as specified. See IGNITION COIL RESISTANCE table. If resistance is not as specified, replace appropriate coil.

IGNITION COIL RESISTANCE (1)

Scheme 21

Scheme 22

Ignition Coil Resistance (Millenia 2.3L)

Ignition coil and ignition control module are integrated as a coil-on-plug unit. Ignition coil testing procedure and resistance specifications are not available from manufacturer. If misfire DTC is present (DTC's P0300-P0306), refer to appropriate Self-Diagnostics article to retrieve codes and diagnose misfire. Misfire diagnostic procedure includes switching ignition coil with a known good ignition coil from another cylinder.

Ignition Coil Resistance (Millenia 2.5L)

1. Disconnect 3-pin harness connector. Using ohmmeter, measure primary resistance between terminals "A" and "B". (Scheme 23) Resistance should be as specified. See «IGNITION COIL RESISTANCE»(ref-134958-S06033891042002022100000) table. If resistance is not as specified, replace distributor.
2. Using an ohmmeter, measure secondary resistance between terminal "A" and coil tower. (Scheme 24) Resistance should be as specified. See «IGNITION COIL RESISTANCE»(ref-134958-S06033891042002022100000) table. If resistance is not as specified, replace distributor.

Scheme 23

Scheme 24

Ignition Coil Resistance (MPV)

1. Disconnect ignition coil connector. Using ohmmeter, measure primary resistance between ignition coil terminals "A" and "B". (Scheme 25) Resistance should be as specified. See «IGNITION COIL RESISTANCE»(ref-134958-S06033891042002022100000) table. If resistance is not as specified, replace coil.
2. Using an ohmmeter, measure secondary resistance between ignition coil terminal "A" and coil tower. See «IGNITION COIL RESISTANCE»(ref-134958-S06033891042002022100000) table. If resistance is not as specified, replace coil.

Scheme 25

Ignition Coil Resistance (626)

1. Disconnect ignition coil harness connector. Using ohmmeter, on 2.0L, measure primary resistance between ignition coil terminals "A" and "B" and terminals "B" and "C". On 2.5L, measure between terminals "A" and "D", "B" and "D" and "C" and "D". (Scheme 26)or (Scheme 27). Resistance should be as specified. See «IGNITION COIL RESISTANCE»(ref-134958-S06033891042002022100000) table. If resistance is not as specified, replace ignition coil.
2. Disconnect high tension leads. Using an ohmmeter, on 2.0L, measure secondary resistance between coil towers No. 1 and 4 and towers No. 2 and 3. On 2.5L, measure secondary resistance between coil towers No. 1 and 4, towers No. 2 and 5 and towers No. 3 and 6. (Scheme 26)or (Scheme 27). Resistance should be as specified. See «IGNITION COIL RESISTANCE»(ref-134958-S06033891042002022100000) table. If resistance is not as specified, replace ignition coil.
3. Measure resistance between terminal "B" (2.0L) or "D" (2.5L) and coil case. Resistance should be more than 10-megohms. If resistance is not as specified, replace coil.

Scheme 26

Scheme 27

Ignition Control Module (Millenia)

Testing information is not available from manufacturer. Check for diagnostic trouble codes. See appropriate SELF-DIAGNOSTICS article.

1. Perform self diagnostic QUICK TEST to check for ignition-related fault codes, and repair as necessary. See QUICK TEST in appropriate SELF-DIAGNOSTICS article. If no fault codes are retrieved, check ignition system wiring harness connectors for corrosion and tight fit. See «WIRING DIAGRAMS»(ref-134975) article. Clean or repair connectors as necessary.
2. If wiring and connectors are okay, use Neon Bulb Spark Tester (D8IP-6666-A) to check for spark at each spark plug wire while cranking engine. If spark is strong and consistent at each spark plug (one spark per crankshaft revolution), ignition system is okay. If spark is not present, go to appropriate SELF-DIAGNOSTICS article.

IDLE SPEED & IGNITION TIMING

Connect scan tool to DLC-2. Ensure idle speed and base ignition timing are set to specification. See IDLE SPEED SPECIFICATIONS and IGNITION TIMING SPECIFICATIONS (DEGREES BTDC @ RPM) tables. If adjustment is necessary, see ON-VEHICLE ADJUSTMENTS article.

IDLE SPEED SPECIFICATIONS

IGNITION TIMING SPECIFICATIONS (DEGREES BTDC @ RPM)

SUMMARY

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed to appropriate SELF-DIAGNOSTICS article. If no hard codes are found in self-diagnostics, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.