Home

< Previous   Next >

2008 - MX-5 - Engine

NO.6 CRANKS NORMALLY BUT WILL NOT START [LF]



6

CRANKS NORMALLY BUT WILL NOT START

DESCRIPTION

  • The starter cranks engine at normal speed but the engine will not run.

  • Refer to symptom troubleshooting "No.5 Engine stalls" if this symptom appears after engine stall.

  • Fuel is in tank.

  • Battery is in normal condition.

POSSIBLE CAUSE

  • No battery power supply to PCM

  • Air leakage from intake-air system

  • Open PCM GND or vehicle body GND

  • Improper operation of electronic throttle control system

  • EGR valve malfunction

  • No signal from CKP sensor due to sensor, related wire or incorrect installation

  • No signal from CMP sensor due to sensor, related wire or incorrect installation

  • Low engine compression

  • Engine overheating

  • Vacuum leakage

  • Erratic signal to ignition coil

  • Improper air/fuel mixture ratio control

  • Poor fuel quality

  • PCV valve malfunction

  • Restriction in intake-air system

  • Restriction in exhaust system

  • Disconnected electrical connector

  • Open or short circuit in fuel pump body and related wiring harness

  • Inadequate fuel pressure

  • Fuel pump mechanical malfunction

  • Fuel leakage from injector

  • Fuel injector is clogged.

  • Purge solenoid valve malfunction

  • Spark plug malfunction

  • Ignition coil malfunction

  • Improper variable valve timing control system operation

  • Improper valve timing

  • Immobilizer system and/or circuit malfunction

  • Immobilizer system operating properly. (Ignition key is not registered.)

  • Pressure regulator malfunction (built-in fuel pump unit)

WARNING:

The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before servicing the fuel system:
  • Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel.

  • Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION" described in this manual.

    (See BEFORE SERVICE PRECAUTION [LF].)

    (See AFTER SERVICE PRECAUTION [LF].)

CAUTION:

  • Disconnecting/connecting quick release connector without cleaning it may cause damage to fuel pipe and quick release connector. Always clean quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.


Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION

1

Connect the M-MDS to the DLC-2.

Do any of the following conditions appear?

  • Engine does not completely start.

  • DTC P1260 is displayed.

Yes

Both conditions appear:

Go to Step 3.

No

Either or other condition appears:

Go to the next step.

2

Does engine stall after approx. 2 s from when it is started?

Yes

Go to the next step.

No

Immobilizer system is normal.

Go to Step 8.

3

Is the coil connector securely connected to the coil?

Yes

Go to the next step.

No

Connect the coil connector securely.

Return to Step 2.

4

Does the security light flush?

Yes

Go to the next step.

No

Inspect and repair or replace the following:

  • Wiring harnesses and connectors from keyless control module terminal 3F and instrument cluster terminal 2F

  • Instrument cluster

(See INSTRUMENT CLUSTER INSPECTION.)

5

Connect the M-MDS to the DLC-2 and retrieve the DTC for PCM, instrument cluster and keyless control module (with advanced keyless entry system).

Are any of the following DTCs displayed?

    DTC
  • PCM: B1342, U0073, U0155

  • Instrument cluster: B1213, B1600, B1601, B1602, B1681, B2103, B2139, B2431, U0100, U0214

  • Keyless control module (with advanced keyless entry system): B1681, B2103, B1213

Yes

Go to the appropriate DTC inspection.

(See DTC TABLE [LF].)

No

Go to the next step.

6

Inspect the following wiring harnesses and connectors:

    With advanced keyless entry system
  • Between coil terminal A and keyless control module terminal 3Y

  • Between coil terminal B and keyless control module terminal 3AA

  • Between keyless control module terminal 4A and instrument cluster terminal 2Q

  • Between keyless control module terminal 4C and instrument cluster terminal 2S

    Without advanced keyless entry system
  • Between coil terminal A and instrument cluster terminal 2S

  • Between coil terminal B and instrument cluster terminal 2Q

Is there any malfunction?

Yes

Repair or replace the suspected wiring harness and connector.

No

Go to the next step.

7

Inspect the following wiring harnesses and connectors:

  • Between PCM terminal 1AM and instrument cluster terminal 1J

  • Between PCM terminal 1AI and instrument cluster terminal 1L

Is there any malfunction?

Yes

Repair or replace the suspected wiring harness and connector.

No

Go to the next step.

8

Verify the following:

  • Vacuum connection

  • External fuel shut off or accessory (such as kill switch, alarm)

  • Fuel quality: proper octane, contamination, winter/summer blend

  • No air leakage from intake-air system

  • Intake-air system restriction (such as air cleaner element, fresh air duct)

  • Proper sealing of intake manifold and components attached to intake manifold: EGR valve

  • Ignition wiring

  • Electrical connections

  • Fuses

  • Smooth operation of throttle valve

Are all items normal?

Yes

Go to the next step.

No

Service if necessary.

Repeat Step 8.

9

Connect the M-MDS to the DLC-2.

Turn the ignition switch to the ON position (Engine off).

Retrieve any DTCs.

Are there any DTCs displayed?

Yes

DTC is displayed:

Go to the appropriate DTC inspection.

(See DTC TABLE [LF].)

Communication error message is displayed:

Inspect for the following:

  • Open circuit in wiring harness between main relay and PCM terminal 1AW or 1BE

  • Open main relay GND circuit

  • Open or short circuit in wiring harness between DLC and PCM terminal 1AM or 1AI

  • Main relay is stuck open.

  • Open or poor GND circuit (PCM terminal 1AZ, 1BB, 1BD, 1BH)

  • Poor connection of vehicle body GND

No

No DTC is displayed:

Go to the next step.

10

Connect the M-MDS to the DLC-2.

Access the APP1 and APP2 PIDs. Crank the engine with accelerator pedal released.

Are the APP1 and APP2 PIDs indicating that the accelerator pedal is in the released position?

Yes

Go to the next step.

No

Inspect for the following:

  • APP sensor

  • Wiring harnesses and connectors for following:

    • PCM terminal 1AJ—APP sensor terminal A

    • PCM terminal 1AV—APP sensor terminal B

    • PCM terminal 1AP—APP sensor terminal C

    • PCM terminal 1AL—APP sensor terminal D

    • PCM terminal 1AS—APP sensor terminal E

    • PCM terminal 1AO—APP sensor terminal F

11

Connect the M-MDS to the DLC-2.

Access the TP PID. Crank the engine with accelerator pedal released.

Are the TP PID indicates the closed throttle position?

Yes

Go to the next step.

No

Inspect for the following:

  • TP sensor

  • Wiring harnesses and connectors for following:

    • PCM terminal 2AK—TP sensor terminal F

    • PCM terminal 2AO—TP sensor terminal E

    • PCM terminal 2AP—TP sensor terminal C

    • PCM terminal 2AL—TP sensor terminal D

12

Does the engine start with the throttle valve closed?

Yes

Go to Step 28.

No

Go to the next step.

13

Will the engine start and run smoothly at part throttle?

Yes

Inspect the electronic throttle control system operation.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF].)

No

Go to the next step.

14

Connect the M-MDS to the DLC-2.

Access RPM PID.

Is RPM PID indicating the engine speed when cranking the engine?

Yes

Go to the next step.

No

Inspect for the following:

  • Open or short circuit in CKP sensor

  • Open or short circuit in wiring harness between CKP sensor terminal A and PCM terminal 2AB

  • Open or short circuit in wiring harness between CKP sensor terminal B and PCM terminal 2W

  • Open or short circuit in wiring harness between CKP sensor terminal C and PCM terminal 2AQ

  • Open or short circuit in CKP sensor wiring harnesses

If CKP sensor and wiring harness are normal, go to the next step.

15

Visually inspect the CKP sensor and teeth of crankshaft pulley.

Are CKP sensor and teeth of crankshaft pulley normal?

Yes

Go to the next step.

No

Replace the malfunctioning part.

16

Inspect the ignition coil related wiring harness condition (intermittent open or short circuit) for all cylinders. Are wiring harness conditions normal?

Yes

Go to the next step.

No

Repair the wiring harnesses.

17

Perform the spark test.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF].)

Is strong blue spark visible at each cylinder?

Yes

Go to the next step.

No

Repair or replace the malfunctioning part according to spark test result.

18

Inspect the spark plug conditions.

Is spark plug wet, covered with carbon or grayish white?

Yes

Spark plug is wet or covered with carbon:

Inspect for fuel leakage from injector.

Spark plug is grayish white:

Inspect the fuel injector for clogging.

No

Install the spark plugs on original cylinders.

Go to the next step.

19

Remove and shake the PCV valve.

Does the PCV valve rattle?

Yes

Go to the next step.

No

Replace the PCV valve.

20

visually inspect the exhaust system part.

Is there any deformed exhaust system part?

Yes

Replace the suspected part.

No

Go to the next step.

21

Install the fuel pressure gauge between the fuel pipe and the fuel distributor.

Short check connector terminal F/P to body GND using a jumper wiring.

Turn the ignition switch to the ON position.

Is fuel line pressure correct when ignition switch is turned on/off five times?

(See FUEL LINE PRESSURE INSPECTION [LF].)

Yes

Go to the next step.

No

Zero or low:

Inspect the fuel pump relay and fuel pump circuit.

Inspect the fuel line for clogging.

If there is no malfunction, replace the fuel pump unit.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF].)

High:

Replace the fuel pump unit.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF].)

22

Visually inspect the fuel injector O-ring and fuel line for fuel leakage.

Service if necessary.

Is the fuel line pressure held after the ignition switch is turned off?

(See FUEL LINE PRESSURE INSPECTION [LF].)

Yes

Go to the next step.

No

Inspect the fuel injector.

If the fuel injector is normal, replace the fuel pump unit.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF].)

23

Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from purge solenoid valve side.

Plug opening end of vacuum hose.

Start the engine.

Is starting condition improved?

Yes

Inspect if the purge solenoid valve is stuck open mechanically.

Inspect the evaporative emission control system.

No

Go to the next step.

24

Is air leakage felt or heard at intake-air system components while racing engine to higher speed?

Yes

Repair or replace the malfunctioning part.

No

Go to the next step.

25

Inspect the engine condition while tapping EGR valve housing.

Is engine condition improved?

Yes

Replace the EGR valve.

No

Go to the next step.

26

Inspect the variable valve timing control system operation.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF].)

Does variable valve timing control function properly?

Yes

Go to the next step.

No

Repair or replace the malfunctioning part.

27

Is the engine compression correct?

Yes

Inspect the valve timing.

No

Inspect for causes.

28

  • Verify test results.

    • If normal, return to diagnostic index to service any additional symptoms.

      (See SYMPTOM DIAGNOSTIC INDEX [LF].)

    • If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis.

      • If vehicle is repaired, troubleshooting completed.

      • If vehicle is not repaired or additional diagnostic information is not available, replace the PCM.

        (See PCM REMOVAL/INSTALLATION [LF].)




< Previous   Next >
Back to Top
© 2012 Mazda North American Operations, U.S.A.