NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE [L3]

BME010300000W14

12

LACK/LOSS OF POWER - ACCELERATION/CRUISE

DESCRIPTION

Performance is poor under load (e.g., power down when climbing hills).

POSSIBLE CAUSE

• Improper A/C system operation
• Erratic signal or no signal from CMP sensor
• Air leakage from intake-air system parts
• Improper VIS operation
• Improper VTCS operation
• Purge control solenoid malfunction
• EGR valve malfunction
• Brake dragging
• Erratic signal from CKP sensor
• Low engine compression
• Vacuum leakage
• Poor fuel quality
• Spark leakage from high-tension leads
• Engine overheating
• Throttle body malfunction
• Spark plug malfunction
• Air cleaner restriction
• PCV valve malfunction
• Improper valve timing due to jumping out of timing belt
• Restriction in exhaust system
• Intermittent open or short in fuel pump related circuit
• Inadequate fuel pressure
• Fuel pump mechanical malfunction
• Fuel line restriction or clogging
• Fuel leakage from fuel injector
• Fuel injector clogging
• Intermittent open or short of MAF sensor, TP sensor and VSS
• Clutch slippage
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 injuries 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.
(See BEFORE REPAIR PROCEDURE [L3].)
(See AFTER REPAIR PROCEDURE [L3].)
Caution
• Disconnecting/connecting quick release connector without cleaning it may possibly 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

1
Verify 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; such as EGR valve, IAC valve
• Fuel quality (e.g. proper octane, contamination, winter/summer blend)
Are all items okay?
Yes
Go to next step.
No
Service as necessary.
Repeat Step 1.
2
Connect WDS or equivalent to DLC-2.
Retrieve any continuous memory, KOEO and KOER DTCs.
If engine stall condition exists, retrieve continuous memory and KOEO DTCs.
Are there any DTCs displayed?
Yes

DTC is displayed:

Go to appropriate DTC test.
No

No DTC is displayed:

Go to next step.
3
Is engine overheating?
Yes
Go to symptom troubleshooting "No.17 Cooling system concerns - Overheating".
No
Go to next step.
4
Connect WDS or equivalent to DLC-2.
Access RPM, MAF, TP and VSS PIDs.
Drive vehicle while monitoring PIDs.
Are PIDs within specifications?
Yes
Go to next step.
No

RPM PID:

Inspect CKP sensor and related wiring harness for vibration and/or intermittent open/short circuit.

MAF PID:

Inspect for intermittent open circuit of MAF sensor and related wiring harness.

TP PID:

Inspect if TP sensor output increases smoothly.

VSS PID:

Inspect for intermittent open circuit of VSS and related wiring harness.
5
Visually inspect CKP sensor and teeth of crankshaft pulley.
Are CKP sensor and teeth of crankshaft pulley okay?
Yes
Go to next step.
No
Replace malfunctioning parts.
6
Measure gap between CKP sensor and teeth of crankshaft pulley.
Specification

0.5-1.9 mm {0.020-0.075 in}

Is gap within specification?
Yes
Go to next step.
No
Adjust CKP sensor.
7
Inspect spark plug condition.
Is 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 for clogged fuel injector.
No
Install spark plugs on original cylinders.
Go to next step.
8
Remove and shake PCV valve.
Does PCV valve rattle?
Yes
Go to next step.
No
Replace PCV valve.
9
Inspect for restriction in exhaust system.
Is there any restriction?
Yes
Inspect exhaust system.
No
Go to next step.
10
Install fuel pressure gauge between fuel pipe and fuel distributor.
Connect jumper wire between F/P terminal at DLC-2 in engine compartment and GND.
Turn ignition switch to ON position.
Is fuel line pressure correct with ignition switch to ON position?
Yes
Go to next step.
No

Zero or low:

Inspect for clogged fuel line.
If okay, replace fuel pump unit.

High:

Replace fuel pump unit.
11
Inspect VTCS operation.
Does VTCS work properly?
Yes
Go to next step.
No
Repair or replace malfunctioning parts.
12
Inspect VIS operation.
Does VIS work properly?
Yes
Go to next step.
No
Repair or replace malfunctioning parts.
13
Note
• Following test is for engine stalling with A/C on concern. If other symptoms exist, go to next step.
Connect pressure gauge to A/C low and high side pressure lines.
Turn A/C on and measure low side and high side pressures.
Are pressures within specifications?
Yes
Go to next step.
No
If A/C is always on, go to symptom troubleshooting "No.24 A/C is always on or A/C compressor runs continuously".
For other symptoms, inspect following:
• Refrigerant charging amount
• Condenser fan operation
14
Inspect for A/C cut-off operation.
Does A/C cut-off work properly?
Yes
Go to next step.
No
Inspect A/C cut-off system components.
15
Disconnect vacuum hose between purge solenoid valve and intake manifold from purge solenoid valve side.
Plug opening end of vacuum hose.
Drive vehicle.
Does engine condition improve?
Yes
Inspect if purge solenoid valve is sticks open mechanically.
Inspect evaporative emission control system.
No
Go to next step.
16
Visually inspect CMP sensor and projections of camshaft pulley.
Are CMP sensor and projections of camshaft pulley okay?
Yes
Go to next step.
No
Replace malfunctioning parts.
17
Inspect EGR system.
Is EGR system okay?
Yes
Go to next step.
No
Replace malfunctioning parts.
18
Is engine compression correct?
Yes
Inspect following:
• Valve timing
• Clutch
• Brake system for dragging
No
Inspect for cause.
19
Verify test results.
• If okay, return to diagnostic index to service any additional symptoms.
• If malfunction remains, replace PCM.