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NO.14 POOR FUEL ECONOMY [L3 Turbo]

id0103b4802000

14 | POOR FUEL ECONOMY
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DESCRIPTION | Fuel economy is unsatisfactory.
POSSIBLE CAUSE | • Contaminated air cleaner element • Engine cooling system malfunction • Weak spark • Spark plug malfunction • Poor fuel quality • Erratic signal from CKP sensor • Erratic or no signal from CMP sensor • Fuel pressure sensor or related circuit malfunction • ECT sensor or related circuit malfunction • Manifold absolute pressure (MAP) sensor or related circuit malfunction • Accelerator position sensor or related circuit malfunction • MAF sensor or related circuit malfunction • Contaminated MAF sensor • IAT sensor No.1 or related circuit malfunction • IAT sensor No.2 or related circuit malfunction • VSS or related circuit malfunction • Variable swirl system malfunction • Improper coolant level • Inadequate fuel pressure (high-pressure side) • Injection timing is incorrect • Fuel injector or related circuit malfunction • High pressure fuel pump malfunction • Fuel leakage • Fuel line restriction • Fuel filter clogging • PCV valve malfunction • Brake dragging • Clutch slippage • A/C system improper operation • Improper valve timing due to jumping out of timing chain • Improper engine compression • Turbocharger malfunction • Charge air cooler malfunction • Exhaust system and/or three-way catalytic converter clogging • EGR system malfunction • Vacuum leakage • Injector driver module 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 ROCEDURE" and "AFTER REPAIR PROCEDURE" described in this manual. (See BEFORE SERVICE PRECAUTION [L3 Turbo].) (See AFTER SERVICE PRECAUTION [L3 Turbo].) Caution • Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and quick release connector. Always clean the 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 | Inspect for the following: • Air cleaner element for contamination • Intake-air system restriction • Fuel quality (proper octane, contamination, winter/summer blend) • Coolant level • Brake dragging • Clutch slippage • Charge air cooler condition (restriction or damaged) • Vacuum leakage • Fuel leakage • MAF sensor contaminated • Exhaust system and/or three-way catalytic converter restriction Are all items normal? | Yes | Go to the next step.
No | Service if necessary. Repeat Step 1.
2 | Perform the self-test function using the WDS or equivalent. Turn the ignition switch to the ON position. Retrieve any DTCs. Is a DTC displayed? | Yes | DTC is displayed: Go to the appropriate DTC test. (See DTC TABLE [L3 Turbo].)
No | No DTC is displayed: Go to the next step.
3 | Perform the Cooling Fan Control System Operation Inspection. (See Cooling Fan Control System Inspection.) Does the EGR system operate properly? | Yes | Go to the next step.
No | Inspect or replace the malfunctioning parts, according to the inspection results.
4 | Perform the EGR system operation inspection. (See EGR Control System Inspection.) Does the EGR system operate properly? | Yes | Go to the next step.
No | Inspect or replace the malfunctioning parts, according to the inspection results.
5 | Perform the Variable Swirl Control System Operation Inspection. (See Variable Swirl System Operation Inspection.) Does the variable swirl system work properly? | Yes | Go to the next step.
No | Inspect or replace the malfunctioning parts, according to the inspection results.
6 | Perform the Wastegate Control System Operation Inspection. (See Wastegate Control System Operation Inspection.) Does the variable swirl system work properly? | Yes | Go to the next step.
No | Inspect or replace the malfunctioning parts, according to the inspection results.
7 | Perform the A/C Cut-off Operation Inspection. (See A/C Cut-off Control System Inspection.) Does the A/C Cut-off Operation work properly? | Yes | Go to the next step.
No | Repair or replace malfunctioning parts, according to the inspection results.
8 | Remove and shake the PCV valve. Does the PCV valve rattle? | Yes | Go to the next step.
No | Replace the PCV valve.
9 | Perform the spark test. (See Spark Test.) Is the strong blue spark visible at each cylinder? | Yes | Go to the next step.
No | Inspect or replace the malfunctioning parts, according to the inspection results.
10 | Inspect CMP and CKP sensor for the following; • Installation condition (See CAMSHAFT POSITION (CMP) SENSOR REMOVAL/INSTALLATION [L3 Turbo].) (See CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION [L3 Turbo].) • Damaged trigger wheel and camshaft • Open or short circuit in the wiring harnesses Is there any malfunction detected? | Yes | Repair or replace the malfunctioning part according to the inspection results.
No | Go to the next step.
11 | Connect the WDS or equivalent to the DLC-2. Access and monitor following PIDs using the data monitor function. • ECT • MAF • IAT • IAT2 • APP • TP • CPP (PCM terminal 1H) • PNP (PCM terminal 1W) • MAP • VSS Do the PIDs indicate the correct values according to the engine operating condition? (See Using the WDS or Equivalent.) | Yes | Go to the next step.
No | Inspect and repair or replace suspected parts and the related harnesses. If the malfunction remains, perform the intermittent concern troubleshooting procedure. (See INTERMITTENT CONCERN TROUBLESHOOTING [L3 Turbo].)
12 | Access and monitor the FUEL_PRES PID. Is the FUEL_PRES PID value within the specification? (See Using the WDS or Equivalent.) | Yes | Go to Step 16.
No | Go to the next step.
13 | Is the vehicle accelerate performance normally? | Yes | Go to the next step.
No | Go to Step 15.
14 | Inspect the fuel pressure sensor. (See FUEL PRESSURE SENSOR INSPECTION [L3 Turbo].) Is the fuel pressure sensor normal? | Yes | Go to Step 16.
No | Replace the delivery pipe.
15 | Replace the high pressure fuel pump. Monitor FUEL_PRES PID. Is the FUEL_PRES PID value within the specified? (See Using the WDS or Equivalent.) | Yes | Troubleshooting is completed. Go to Step 19.
No | Go to the next step.
16 | Inspect the turbocharger. (See TURBOCHARGER INSPECTION [L3 Turbo].) Is there any problem in turbocharger? | Yes | Replace the turbocharger.
No | Go to the next step.
17 | Inspect the fuel injector for each cylinder. (See FUEL INJECTOR INSPECTION [L3 Turbo].) Are fuel injectors normal? | Yes | Go to the next step.
No | Replace the suspected fuel injector. (See FUEL INJECTOR REMOVAL/INSTALLATION [L3 Turbo].)
18 | Measure the compression pressure for each cylinder. (See COMPRESSION INSPECTION [L3 Turbo].) Are compression pressures within the specification? | Yes | Replace the injector driver module. If the problem remains, overhaul the engine.
No | Inspect for 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.
19 | Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. • If a malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform the repair or diagnosis. - If the vehicle is repaired, troubleshooting is completed. - If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.