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NO.16 POOR FUEL ECONOMY [MZR-CD (RF Turbo)]

id0103f1821400

16 | POOR FUEL ECONOMY
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DESCRIPTION | • Fuel economy is unsatisfactory.
POSSIBLE CAUSE | • Incorrect idle speed • A/C system improper operation • Intake -air system clogging or restriction • Engine cooling system malfunction • Poor fuel quality • Improper coolant level • Erratic signal from CKP sensor • Erratic signal from CMP sensor • Fuel pressure sensor or related circuit malfunction • ECT sensor or related circuit malfunction • Boost sensor or related circuit malfunction • Accelerator pedal position (APP) sensor or related circuit malfunction • MAF/IAT sensor or related circuit malfunction • IAT sensor No.2 or related circuit malfunction • VSS or related circuit malfunction • Turbocharger malfunction • Charge air cooler malfunction • Low engine compression • Improper valve timing • Exhaust system and/or oxidation catalytic converter clogging • Incorrect fuel injection timing • Fuel injector malfunction • Supply pump malfunction • Fuel leakage • Fuel line clogging or restriction • Fuel filter clogging or restriction • Brake dragging • EGR system malfunction • Vacuum leakage • Clutch slippage • Variable boost control (VBC) system malfunction • Coolant heater system malfunction • Fuel injection learning improper 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
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1 | Inspect the following: • Fuel quality (e.g.: including water contamination, winter/summer blend) • Fuel line/fuel filter clogging and/or restriction • Fuel line leakage • Intake-air system restriction • Exhaust system and/or oxidation catalytic converter restriction • Charge air cooler condition (restriction or damaged) • Vacuum leakage Are all items normal? | Yes | Go to the next step.
No | Service if necessary. Repeat Step 1.
2 | Is the brake system functioning properly? | Yes | Go to the next step.
No | Inspect for cause.
3 | Perform the self-test function using the WDS or equivalent. Turn the engine switch to the ON position. Retrieve any DTCs. Are any DTCs displayed? | Yes | DTC is displayed: Go to the appropriate DTC test. (See DTC TABLE [MZR-CD (RF Turbo)].) Communication error message is displayed: Inspect the following: • Open circuit between PCM control relay and PCM terminal 119 or 120 • Open circuit PCM control relay and PCM terminal 105 • PCM control relay stuck open • Open or poor ground circuit (PCM terminal 1, 2, 3, 114 or 117) • Poor connection to vehicle body ground
No | No DTC is displayed: Go to the next step.
4 | Start the engine and warm up to normal operation temperature. Verify the diesel particulate filter lamp condition. Does the diesel particulate filter lamp illuminate or flash? | Yes | Diesel particulate filter lamp illuminates: Perform the manual diesel particulate filter regeneration procedure. (See DIESEL PARTICULATE FILTER REGENERATION [MZR-CD (RF Turbo)].) Diesel particulate filter lamp flashes: Perform the fuel injection learning, diesel particulate filter initialize, and clearing PCM memory then go to the next step. (See Injection amount correction.) (See DIESEL PARTICULATE FILTER RESET [MZR-CD (RF Turbo)].) (See DIESEL PARTICULATE FILTER DATA RESET [MZR-CD (RF Turbo)].)
No | Go to the next step.
5 | Note • The following test should be performed on the vehicles with an A/C system. If the following test cannot be performed due to engine stalling, go to the next step. • Go to the next step for vehicles without n A/C system Connect the pressure gauge to the A/C line. Turn the blower and A/C switches on. Is the pressure within the specifications? | Yes | Go to the next step.
No | A/C is always on: Go to the symptom troubleshooting "NO.26 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZR-CD (RF-Turbo)]". Other symptoms: Inspect the following: • Refrigerant charging amount • Cooling fan operation
6 | Access the ECT PID. Drive the vehicle while monitoring the PID. Is the PID within the specification? | Yes | Go to the next step.
No | Inspect for coolant leakage, cooling fan operation or thermostat operation.
7 | Inspect the idle speed. (See ENGINE TUNE-UP [MZR-CD (RF Turbo)].) Is the idle speed normal? | Yes | Go to the next step.
No | Go to symptom troubleshooting "NO.9 SLOW RETURN TO IDLE [MZR-CD (RF-Turbo)]".
8 | Perform the EGR system inspection. Is the EGR system normal? | Yes | Go to the next step.
No | Repair or replace the malfunctioning part according to the EGR system operation results.
9 | Inspect the APP sensor. (See ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZR-CD (RF Turbo)].) Is the APP sensor normal? | Yes | Go to the next step.
No | Replace the accelerator pedal component.
10 | Is the engine compression correct? (See COMPRESSION INSPECTION [MZR-CD (RF Turbo)].) | Yes | Go to the next step.
No | Inspect the 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 if necessary.
11 | Inspect the fuel injector. (See FUEL INJECTOR INSPECTION [MZR-CD (RF Turbo)].) Is the fuel injector normal? | Yes | Go to the next step.
No | Repair or replace if necessary. (See FUEL INJECTOR REMOVAL/INSTALLATION [MZR-CD (RF Turbo)])
12 | Perform the turbocharger inspection. (See TURBOCHARGER INSPECTION [MZR-CD (RF Turbo)].) Is the turbocharger normal? | Yes | Go to the next step.
No | Replace the turbocharger.
13 | Inspect the guide blade valve operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR-CD (RF Turbo)].) Is the there any malfunction? | Yes | Repair or replace if necessary.
No | Go to the next step.
14 | Visually inspect the CKP sensor and the teeth of the pulse wheel. Are the CKP sensor and the teeth of the pulse wheel normal? | Yes | Go to the next step.
No | Replace the malfunctioning parts.
15 | Measure the gap between the CKP sensor and the teeth of the pulse wheel. Specification 1.5-2.5 mm {0.059-0.098 in} Is the gap within the specification? | Yes | Go to the next step.
No | Adjust the CKP sensor position.
16 | Visually inspect the CMP sensor and the teeth of the pulse wheel. Are the CMP sensor and the teeth of the pulse wheel normal? | Yes | Inspect the following PIDs: (See PCM INSPECTION [MZR-CD (RF Turbo)].) • ECT • IAT • MAF • MAP • RPM • VSS If the PID value is not as specified, repair or replace malfunctioning parts. If the PID value is normal, go to the next step.
No | Replace malfunctioning parts.
17 | Inspect the timing belt for the following: • Chipping of gear teeth • Low tension • Breakage damage or cracks Is the timing belt normal? | Yes | Inspect the following: • Clutch slippage • CKP sensor • Boost sensor and related circuit • Brake system for dragging • Coolant heater system • Glow system If normal, remove and inspect supply pump.
No | If the timing is incorrect, adjust the valve timing. If the timing belt is not normal, replace the timing belt.
18 | Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR-CD (RF Turbo)].) • If the malfunction remains, inspect the related Service Information and perform repair or diagnosis. - If the vehicle is repaired, troubleshooting completed. - If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if later calibration is available. Retest.