NO.10 LACK/LOSS OF POWER [WLT-1, WLT-2]

id010396913000

10
Lack/loss of power—acceleration/cruise
DESCRIPTION
•  Performance is poor under load (e.g., powers down when climbing hills).
POSSIBLE CAUSE
•  Poor fuel quality
•  Air leakage from intake-air system
•  Intake-air system restriction
•  Air cleaner restriction
•  Engine overheating
•  A/C system improper operation
•  EGR system malfunction
•  Clutch slippage
•  Exhaust system restriction
•  Fuel line restriction
•  Fuel filter clogging
•  Fuel inlet-filter restriction or clogging
•  Incorrect fuel injection timing
•  Incorrect idle speed
•  Injection pump malfunction
•  Injection nozzle malfunction
•  Low engine compression pressure
•  Turbocharger malfunction
•  Brake system dragging

Diagnostic procedure

STEP

INSPECTION

ACTION
1
•  Is the idle speed stable?
Yes
Go to the next step.
No
Go to symptom troubleshooting "NO.7 ENGINE RUNS ROUGH/ROLLING IDLE."
2
•  Is the engine overheating?
Yes
Go to symptom troubleshooting "NO.13 COOLING CONCERNS-OVERHEATING."
No
Go to the next step.
3
•  Connect the pressure gauge to A/C lines.
•  Turn the fan switch on.
•  Is the pressure within specification?
Yes
Go to the next step.
No
A/C is always on:
•  Go to symptom troubleshooting "NO.19 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY."
For other symptoms:
•  Inspect the following:
―  Refrigerant charging amount
―  Cooling fan operation
4
•  Inspect the air cleaner and/or intake-air system for clogging or restriction.
•  Are the air cleaner and intake-air system normal?
Yes
Go to the next step.
No
Clean or replace if necessary.
5
Note
•  The following test should be performed on vehicles with the turbocharger system.
•  Go to Step 16 for vehicles without the turbocharger system.
•  Inspect the hose bands between following parts:
―  Turbocharger compressor housing and air cleaner
―  Turbocharger compressor housing and charge air cooler
•  Are the hose bands loose?
Yes
Retighten hose bands.
If concern is resolved, complete inspection.
If concern still exists, go to the next step.
No
Turbocharger is normal.
Go to the next step.
6
•  Inspect the wastegate actuator for improper operation, kinks, clogs, or disconnection.
•  Is the actuator normal?
Yes
Go to the next step.
No
Repair or replace as necessary.
If the concern is resolved, complete the inspection.
If the concern still exists, the turbocharger is normal.
Go to the next step.
7
•  Remove parts necessary to inspect the turbocharger. Do not remove the turbocharger.
•  Inspect if the turbocharger compressor wheel is bent, damaged, or interfering with the housing on vehicle.
•  Is there any problem?
Yes
Replace the turbocharger.
No
Go to the next step.
8
•  Inspect if the turbocharger compressor wheel locknut is loose or has fallen down inside the turbocharger.
•  Is there any problem?
Yes
Replace the turbocharger.
No
Go to the next step.
9
•  Turn turbocharger compressor wheel by hand.
•  Does the wheel turn easily and smoothly?
Yes
Go to the next step.
No
Replace the turbocharger.
10
•  Inspect if the turbocharger turbine wheel is damaged, cracked or interfering with the housing on the vehicle.
Note
•  Inspect all fins on each turbine wheel.
•  Is there any problem?
Yes
Replace the turbocharger.
No
Go to the next step.
11
•  Is any engine oil found inside the turbocharger turbine housing?
Yes
Excessive amount of oil is found:
•  Replace the turbocharger.
Small amount of oil is found:
•  Wipe oil out of the vehicle, then go to the next step.
No
Go to the next step.
12
•  Is any engine oil found inside the turbocharger compressor housing?
Yes
Wipe the oil out of the vehicle and install all removed parts in Step 7.
Go to the next step.
No
Turbocharger is normal.
Install all removed parts in Step 7.
Go to the next step.
13
•  Remove the injection nozzle.
•  Inspect the injection nozzle for the following:
―  Clogged nozzle
―  Seized needle valve
―  Incorrect valve opening pressure
―  Malfunctioning nozzle gasket
•  Is the injection nozzle normal?
Yes
Go to the next step.
No
Clogged nozzle or seized needle valve:
•  Disassemble and clean or replace the injection nozzle.
Incorrect valve opening pressure:
•  Adjust injection nozzle opening pressure.
Malfunctioning nozzle gasket:
•  Replace nozzle gasket.
14
•  Is there any restriction in exhaust system?
Yes
Repair or replace if necessary.
No
Go to the next step.
15
•  Inspect fuel leakage from pipe.
•  Is any fuel leakage found on fuel pipe?
Yes
Repair or replace as necessary.
No
Go to the next step.
16
•  Inspect the fuel filter for clogging.
•  Is the fuel filter normal?
Yes
Go to the next step.
No
Replace the fuel filter cartridge.
17
•  Inspect the fuel-inlet filter for restriction and/or clogging.
•  Is the fuel-inlet filter normal?
Yes
Go to the next step.
No
Replace or cleanup the fuel-inlet filter.
Then go to the next step.
18
Note
•  The following test should be performed on vehicles with EGR system. Go to next step for vehicles without EGR system.
•  Carry out EGR system inspection.
•  Is the EGR system normal?
Yes
Go to the next step.
No
Repair or replace as necessary.
19
•  Measure the engine compression.
•  Is the compression normal?
Yes
Go to Step 21.
No
Go to the next step.
20
•  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:
•  Burnt valve
•  Worn piston, piston ring or cylinder
•  Damaged cylinder head gasket
•  Damaged valve seat
•  Worn valve stem and valve guide
Repair or replace if necessary.
No
If the timing is incorrect, adjust the timing.
If the timing belt is not normal, replace the timing belt.
21
•  Inspect the injection timing.
•  Is the injection timing normal?
Yes
Inspect the following:
•  Brake system for dragging
•  Clutch for slippage
•  FIP
If the normal, remove and the inspect injection pump.
No
Inspect the TCV.
(See TIMER CONTROL VALVE (TCV) INSPECTION [WLT-1, WLT-2].)
If the TCV is normal, adjust the injection timing.
22
•  Verify the test results. If normal, return to the diagnostic index to service any additional symptoms.