NO.11 ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE, SURGES [L3]

BME010300000W13

11

ENGINE STALLS/QUITS - ACCELERATION/CRUISE

ENGINE RUNS ROUGH - ACCELERATION/CRUISE

MISSES - ACCELERATION/CRUISE

BUCK/JERK - ACCELERATION/CRUISE/DECELERATION

HESITATION/STUMBLE - ACCELERATION

SURGES - ACCELERATION/CRUISE

DESCRIPTION

• Engine stops unexpectedly at beginning of acceleration or during acceleration.
• Engine stops unexpectedly while cruising.
• Engine speed fluctuates during acceleration or cruising.
• Engine misses during acceleration or cruising.
• Vehicle bucks/jerks during acceleration, cruising, or deceleration.
• Momentary pause at beginning of acceleration or during acceleration
• Momentary minor irregularity in engine output

POSSIBLE CAUSE

• A/C system operation is improper.
• Erratic signal or no signal from CMP sensor
• Air leakage from intake-air system parts
• Purge solenoid valve malfunction
• IAC valve improper operation
• EGR valve malfunction
• Erratic signal from CKP sensor
• Low engine compression
• Vacuum leakage
• Poor fuel quality
• Main relay intermittent malfunction
• Throttle body malfunction
• Engine overheating
• Spark plug malfunction
• Improper air/fuel mixture ratio control operation
• Improper VTCS operation
• Spark leakage from high-tension leads
• Air cleaner restriction
• PCV valve malfunction
• Improper valve timing due to jumping out timing belt
• Restriction in exhaust system
• Intermittent open or short in fuel body pump circuit
• Inadequate fuel pressure
• Fuel pump mechanical malfunction
• Fuel leakage from fuel injector
• Fuel injector clogging
• Fuel line restriction or clogging
• Pressure regulator malfunction
• TP sensor misadjustment
• Intermittent open or short of MAF sensor, TP sensor and VSS
• Clutch slippage
• Improper VTCS operation
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 for 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
• Ignition wiring
• Fuel quality (e.g. proper octane, contamination, winter/summer blend)
• Electrical connections
• Smooth operation of throttle valve
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 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, VPWR, MAF, TP and VSS PIDs.
Drive vehicle with monitoring PIDs.
Are PIDs within specifications?
Yes
Go to next step.
No

RPM PID:

Inspect CKP sensor and related harness for such as vibration, intermittent open/short circuit.

VPWR PID:

Inspect for open circuit intermittently.

MAF PID:

Inspect for open circuit of MAF sensor and related wire harness intermittently.

TP PID:

Inspect if output signal from TP sensor changes smoothly.

VSS PID:

Inspect for open circuit of VSS and related wire harness intermittently.
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 conditions.
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
Verify that throttle lever is resting on throttle valve stop screw and/or throttle valve orifice plug.
Is lever in correct position?
Yes
Go to next step.
No
Adjust if necessary.
10
Inspect for restriction in the exhaust system.
Is there any restriction?
Yes
Inspect exhaust system.
No
Go to next step.
11
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.
12
Visually inspect for fuel leakage at fuel injector O-ring and fuel line.
Service as necessary.
Is fuel line pressure held after ignition switch is turned off?
Yes
Go to next step.
No
Inspect fuel injector.
If fuel injector is okay, replace fuel pump unit.
13
Note
• Following test is for engine stalling with A/C on. If other symptom exists, go to next step.
Connect a pressure gauge to A/C low and high pressure side lines.
Turn A/C on and measure low side and high side pressure.
Are pressure 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
Note
• The following test should be performed for symptom with cruise control ON. If other symptoms exist, go to next step.
Inspect cruise control system.
Is cruise control system okay?
Yes
Go to next step.
No
Repair or replace malfunctioning parts.
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
Go to next step.
Inspect if purge solenoid valve 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 VTCS operation.
Is VTCS okay?
Yes
Go to next step.
No
Replace or replace malfunctioning parts.
18
Inspect EGR system.
Is EGR system okay?
Yes
Go to next step.
No
Replace malfunctioning parts.
19
Is engine compression correct?
Yes
Inspect following:
• Valve timing
• Clutch
No
Inspect for cause.
20
Verify test results.
• If okay, return to diagnostic index to service any additional symptoms.
• If malfunction remains, replace PCM.