NO.5 ENGINE STALLS-AFTER START/AT IDLE [MZI-3.7]

id0103d2801100

5 | ENGINE STALLS—AFTER START/AT IDLE
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DESCRIPTION | • Engine stops unexpectedly.
POSSIBLE CAUSE | • Vacuum leakage • Air leakage from intake-air system parts • Air cleaner restriction • Poor fuel quality • Electrical connector disconnection • Throttle valve restriction or clogged • PCM DTC is stored. • No battery power supply to PCM or poor ground • Erratic signal to PCM ― APP sensor or related circuit malfunction ― TP sensor or related circuit malfunction • Improper operation of drive-by-wire control system • Restriction in exhaust system • No signal from CKP sensor due to sensor, related wire or wrong installation • Ignition coil or related circuit malfunction • Spark plug malfunction • Fuel leakage from fuel injector • Fuel injector clogging • Inadequate fuel pressure ― Open or short circuit in fuel pump and related wiring harness ― Fuel pump mechanical malfunction ― Fuel line clogged ― Pressure regulator malfunction (built-in fuel pump unit) • Fuel leakage from fuel system • PCV valve malfunction • A/C system operation is improper. • Purge solenoid valve malfunction • Air leakage from intake air system when the engine runs high speed • Improper operation variable valve timing control system • Low engine compression • Improper valve timing 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 [MZI-3.7].)(See AFTER SERVICE PRECAUTION [MZI-3.7].) 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
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1 | Verify the following: • Vacuum connection • Air cleaner element • No air leakage from intake-air system • No restriction of intake-air system • Proper sealing of intake manifold and components attached to intake manifold • Ignition wiring • Fuel quality: proper octane, contamination, winter/summer blend • Electrical connections • Smooth operation of throttle valve Are all items normal? | Yes | Go to the next step.
No | Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
2 | Turn the ignition switch to the ON position (Engine off). Retrieve any PCM DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7].) Are there any DTCs displayed? | Yes | DTC is displayed: • Go to the appropriate DTC inspection. (See DTC TABLE [MZI-3.7].) Communication error message is displayed: Inspect for the following: • Main relay No.1 is stuck open. • Poor connection of vehicle body ground • Open circuit in wiring harness between main relay No.1 and PCM terminal 1BK or 1BP • Open circuit in wiring harness between main relay No.1 and PCM terminal 1AZ • Open or short circuit in wiring harness between DLC-2 and PCM terminals 1AH or 1AL • Open or poor ground circuit (PCM terminal 1B, 1E, 1J) Repair or replace the malfunctioning part according to the inspection results.
No | No DTC is displayed: • Go to the next step.
3 | Access the following PCM PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7].) • APP1 • APP2 Crank the engine with the accelerator pedal released. Are the PIDs indicating that the accelerator pedal is in the released position? | Yes | Go to the next step.
No | Inspect for the following: • APP sensor (See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZI-3.7].) • Wiring harnesses and connectors for following: ― PCM terminal 1Z—APP sensor terminal A ― PCM terminal 1U—APP sensor terminal B ― PCM terminal 1AD—APP sensor terminal C ― PCM terminal 1AB—APP sensor terminal D ― PCM terminal 1Y—APP sensor terminal E ― PCM terminal 1X—APP sensor terminal F Repair or replace the malfunctioning part according to the inspection results.
4 | Access the PCM PIDs TP1, TP2 using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7].) Crank the engine with the accelerator pedal released. Are the TP1, TP2 PID indicates the closed throttle position? | Yes | Go to the next step.
No | Inspect for the following: • TP sensor (See THROTTLE POSITION (TP) SENSOR INSPECTION [MZI-3.7].) • Wiring harnesses and connectors for following: ― PCM terminal 2BO—TP sensor terminal A ― PCM terminal 2BR—TP sensor terminal B ― PCM terminal 2AL—TP sensor terminal C ― PCM terminal 2AP—TP sensor terminal D ― PCM terminal 2Z—TP sensor terminal E ― PCM terminal 2AN—TP sensor terminal F Repair or replace the malfunctioning part according to the inspection results.
5 | Attempt to start the engine at part throttle. Does the engine run smoothly at part throttle? | Yes | Inspect the drive-by-wire control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7].) Repair or replace the malfunctioning part according to the inspection results.
No | Go to the next step.
6 | Visually inspect the exhaust system part. Is there any deformed exhaust system part? | Yes | Repair or replace the malfunctioning part according to the inspection results.
No | Go to the next step.
7 | Access the PCM PID RPM using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7].) Is the RPM PID indicating the engine speed during the engine cranking? | Yes | Go to the next step.
No | Inspect for the following: • Open or short circuit in CKP sensor • Open or short circuit in CKP sensor wiring harnesses • Open or short circuit in wiring harness between CKP sensor terminal A and PCM terminal 2V • Open or short circuit in wiring harness between CKP sensor terminal B and PCM terminal 2R Repair or replace the malfunctioning part according to the inspection results. • If CKP sensor and wiring harness are normal, go to the next step.
8 | Inspect the CKP sensor. (See CRANKSHAFT POSITION (CKP) SENSOR INSPECTION [MZI-3.7].) Is the CKP sensor normal? | Yes | Go to the next step.
No | Repair or replace the malfunctioning part according to the inspection results.
9 | 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 or replace suspected wiring harness and connector.
10 | Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7].) Is strong blue spark visible at each cylinder? | Yes | Go to the next step. • If symptoms occurs with the A/C on, go to Step 15.
No | Repair or replace the malfunctioning part according to the inspection results.
11 | Verify the spark plug conditions when the spark plug removed in Step 10. Is the spark plug wet, covered with carbon or grayish white? | Yes | Spark plug is wet or covered with carbon: • Inspect for fuel leakage from fuel injector. Spark plug is grayish white: • Inspect the fuel injector for clogging. Repair or replace the malfunctioning part according to the inspection results.
No | Install the spark plugs on original cylinders. Go to the next step.
12 | Inspect the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7].) Is the fuel line pressure correct? | Yes | Go to the next step.
No | Zero or low: • Inspect the following: ― Fuel pump relay ― Fuel pump circuit ― Fuel line for clogging • If there is no malfunction, replace the fuel pump unit. (Fuel pump or pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7].) High: • Replace the fuel pump unit. (Pressure regulator malfunction) (See FUEL PUMP UNIT REMOVAL/INSTALLATION [MZI-3.7].)
13 | Visually inspect for fuel leakage at fuel injector, O-ring, and fuel line. Is there any fuel leakage? | Yes | Repair or replace the malfunctioning part according to the inspection results.
No | Go to the next step.
14 | Note • The PCV valve cannot be reassembled once it is removed because the tabs will have bee n broken. Inspect the PCV valve without removing it from the vehicle. Inspect the PCV valve with it installed. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE INSPECTION [MZI-3.7].) Is the PCV valve normal? | Yes | Go to the next step.
No | Replace the PCV valve. (See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [MZI-3.7].)
15 | Note • The following test is for stall concerns with the A/C on. If other symptoms exist, go to the next step. Connect the pressure gauges to A/C low and high pressure side lines. Turn the A/C on and measure low side and high side pressures. (See REFRIGERANT PRESSURE CHECK.) Are pressures within specifications? | Yes | Go to the next step.
No | If the A/C is always on: • Go to the symptom troubleshooting “NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY”. (See NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZI-3.7].) For other symptoms: • Inspect the following: ― Refrigerant charging amount ― Condenser fan operation • Repair or replace the malfunctioning part according to the inspection results.
16 | Disconnect the vacuum hose between purge solenoid valve and intake manifold from purge solenoid side. Plug opening end of vacuum hose. Start the engine. Is the engine stall now eliminated? | Yes | Inspect the following: • If purge solenoid valve is stuck open. • EVAP control system Repair or replace the malfunctioning part according to the inspection results.
No | Go to the next step.
17 | Is air leakage felt or heard at intake-air system components while racing the engine to higher speed? | Yes | Repair or replace the malfunctioning part according to the inspection results.
No | Go to the next step.
18 | Inspect the variable valve timing control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7].) Does the variable valve timing control function properly? | Yes | Go to the next step.
No | Repair or replace the malfunctioning part according to the inspection results.
19 | Is the engine compression correct? | Yes | Inspect the valve timing. Repair or replace the malfunctioning part according to the inspection results.
No | Inspect for cause. Repair or replace the malfunctioning part according to the inspection results.
20 | • Verify test results. ― If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7].) ― If malfunction remains, inspect related Service 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 [MZI-3.7].)