NO.10 LOW IDLE/STALLS DURING DECELERATION [MZR-CD (RF Turbo)]

BME010300000W45

10

LOW IDLE/STALLS DURING DECELERATION

DESCRIPTION

• Engine stops unexpectedly at beginning of deceleration or recovery from deceleration.

POSSIBLE CAUSE

• Intake-air system restriction
• Poor fuel quality
• A/C system improper operation
• Inadequate fuel pressure
• Suction control valve malfunction (built-in supply pump)
• Fuel pressure limiter malfunction (built-in common rail)
• Fuel leakage
• Fuel line restriction
• Fuel filter clogging
• Incorrect fuel injection timing
• Improper idle speed
• Erratic signal from CKP sensor
• Erratic signal from CMP sensor
• Supply pump malfunction
• Fuel injector malfunction
• Low engine compression
• Improper valve timing
• Glow system malfunction
• EGR system malfunction
• Vacuum leakage
• MAF/IAT sensor or related circuit malfunction
• ECT sensor or related circuit malfunction
• Fuel pressure sensor or related circuit malfunction
• Neutral switch malfunction or related circuit malfunction
• Clutch switch malfunction or related circuit malfunction
• Accelerator position sensor or related circuit malfunction
• Idle switch or related circuit malfunction
• Incorrect adjustment accelerator position sensor and/or idle switch
• IDM or related circuit malfunction
Warning
The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services:
• 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 injury or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE REPAIR PROCEDURE" and "AFTER REPAIR PROCEDURE" described in this manual.

Diagnostic Procedure

STEP

INSPECTION

RESULTS

ACTION

1
Does engine idle rough?
Yes
Go to symptom troubleshooting "NO.8 ENGINE RUNS ROUGH/ROLLING IDLE".
No
Go to next step.
2
Inspect for following:
• Fuel line/fuel filter clogging
• Intake-air system restriction
• Vacuum leakage
• Fuel quality (e.g.: include water contamination, winter/summer blend)
Are all items okay?
Yes
Go to next step.
No
Service as necessary.
Repeat Step 2.
3
Perform self-test function using WDS or equivalent.
Turn engine switch to ON.
Retrieve any DTC.
Is DTC displayed?
Yes

DTC is displayed:

Go to appropriate DTC test.

Communication error message is displayed:

Inspect for following:
• Open circuit between PCM control relay and PCM terminal 53 or 79
• Open circuit PCM control relay and PCM terminal 69
• PCM control relay stuck open
• Open or poor GND circuit (PCM terminal 65, 85, 103 or 104)
• Poor connection vehicle body GND
No

No DTC is displayed:

Go to next step.
4
Inspect idle speed.
Is idle speed correct?
Yes
Go to next step.
No
Repair or replace malfunctioning part according to idle speed inspection results.
5
Inspect adjustment of accelerator position sensor and idle switch.
Are accelerator position sensor and idle switch adjusted correctly?
Yes
Go to next step
No
Adjust accelerator position sensor and idle switch correctly.
6
Measure voltage PCM terminal 33 and 56.
Are voltages okay?
Yes
Go to next step.
No

PCM terminal 33 does not specified:

Inspect clutch switch and related harness.

PCM terminal 56 does not specified:

Inspect neutral switch and related harness.
7
Visually inspect CKP sensor and teeth of pulse wheel.
Are CKP sensor and teeth of pulse wheel okay?
Yes
Go to next step.
No
Replace malfunctioning parts.
8
Measure gap between CKP sensor and teeth of pulse wheel.

Specification

1.5-2.5 mm {0.059-0.098 in}

Is gap within specification?
Yes
Go to next step.
No
Adjust CKP sensor position.
9
Visually inspect CMP sensor and teeth of pulse wheel.
Are CMP sensor and teeth of pulse wheel okay?
Yes
Inspect following PIDs:
• ECT
• IAT
• MAF
• RPM
If PID value is not as specified, repair or replace malfunctioning parts.
If PID value is okay, go to next step.
No
Replace malfunctioning parts.
10
Inspect fuel pressure sensor.
Is fuel pressure okay?
Yes
Go to next step.
No
Replace common rail.
11
Inspect suction control valve.
Is suction control valve okay?
Yes
Go to next step.
No
Repair supply pump.
12
Is engine compression correct?
Yes
Go to next step.
No
Inspect for following:
• Damaged valve seat
• Worn valve stem and valve guide
• Worn or stuck piston ring
• Worn piston, piston ring or cylinder
• Improper valve timing
Service as necessary.
13
Inspect fuel injector.
Is fuel injector okay?
Yes
Go to next step.
No
Repair or replace as necessary.
14
Note
• The following test should be performed on the vehicles with A/C system. If the following test cannot be performed due to engine stalling, go to next step.
• Go to next step for the vehicle without A/C system.
Connect pressure gauge to A/C line.
Turn blower and A/C switches on.
Is pressure within specifications?
Yes
Go to next step.
No

A/C is always on:

Go to symptom troubleshooting "NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY".

Other symptoms:

Inspect following:
• Refrigerant charging amount
• Cooling fan and/or condenser fan operation
15
Inspect EGR system operation.
Is EGR system operation normal?
Yes
Go to next step.
No
Repair or replace malfunctioning part according to EGR system operation results.
16
Inspect glow system operation.
Is glow system operation normal?
Yes
Remove and inspect supply pump and common rail.
No
Service as necessary.
17
Verify test results.
• If okay, return to diagnostic index to service any additional symptoms.
• If malfunction remains, replace PCM. (See PCM REMOVAL/INSTALLATION [MZR-CD (RF Turbo)].)