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

BME010300103249

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 SERVICE PRECAUTION" and "AFTER PRECAUTION" described in this manual.
(See BEFORE SERVICE PRECAUTION [L3].)
(See AFTER SERVICE PRECAUTION [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 the 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 normal?
Yes
Go to the next step.
No
Service if necessary.
Repeat Step 1.
2
Connect the WDS or equivalent to the DLC-2.
Retrieve any continuous memory, KOEO and KOER DTCs.
If stall, condition exists retrieve continuous memory and KOEO DTCs.
Are there DTCs displayed?
Yes

DTC is displayed:

Go to the applicable DTC inspection.
No

No DTC is displayed:

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

RPM PID:

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

VPWR PID:

Inspect for open circuit intermittently.

MAF PID:

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

TP PID:

Inspect if output signal from the TP sensor changes smoothly.

VSS PID:

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

0.5-1.9 mm {0.020-0.075 in}

Is the gap within the specification?
Yes
Go to the next step.
No
Adjust the CKP sensor.
7
Inspect the spark plug conditions.
Is the spark plug wet, covered with carbon or grayish white?
Yes

Spark plug is wet or covered with carbon:

Inspect for fuel leakage from the fuel injector.

Spark plug is grayish white:

Inspect for the clogged fuel injector.
No
Install spark plugs on original cylinders.
Go to the next step.
8
Remove and shake the PCV valve.
Does the PCV valve rattle?
Yes
Go to the next step.
No
Replace the PCV valve.
9
Verify that the throttle lever is resting on the throttle valve stop screw and/or the throttle valve orifice plug.
Is the lever in correct position?
Yes
Go to the next step.
No
Adjust if necessary.
10
Inspect for restriction in the exhaust system.
Is there any restriction?
Yes
Inspect the exhaust system.
No
Go to the next step.
11
Install a fuel pressure gauge between the fuel pipe and the fuel distributor.
Connect a jumper wire between F/P terminal at the DLC-2 in engine compartment and GND.
Turn the ignition switch to the ON position.
Is fuel line pressure correct with the ignition switch at the ON position?
Yes
Go to the next step.
No

Zero or low:

Inspect for clogged fuel line.
If normal, replace the fuel pump unit.

High:

Replace the fuel pump unit.
12
Visually inspect for fuel leakage at the fuel injector O-ring and fuel line.
Service if necessary.
Is fuel line pressure held after the ignition switch is turned off?
Yes
Go to the next step.
No
Inspect the fuel injector.
If the fuel injector is normal, replace the fuel pump unit.
13
Note
• The following test is for engine stalling with A/C on. If other symptom exists, go to the next step.
Connect a pressure gauge to A/C low and high pressure side lines.
Turn the A/C on and measure low side and high side pressure.
Are a pressure within the specifications?
Yes
Go to the next step.
No
If the 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 the 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 the next step.
Inspect the cruise control system.
Is the cruise control system normal?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part.
15
Disconnect vacuum hose between the purge solenoid valve and the intake manifold from the purge solenoid valve side.
Plug opening end of vacuum hose.
Drive the vehicle.
Does the engine condition improve?
Yes
Go to the next step.
Inspect if the purge solenoid valve sticks open mechanically.
Inspect the evaporative emission control system.
No
Go to the next step.
16
Visually inspect the CMP sensor and projections of the camshaft pulley.
Are the CMP sensor and projections of the camshaft pulley normal?
Yes
Go to the next step.
No
Replace the malfunctioning part.
17
Inspect the VTCS operation.
Is the VTCS normal?
Yes
Go to the next step.
No
Replace or replace the malfunctioning part.
18
Inspect the EGR system.
Is the EGR system normal?
Yes
Go to the next step.
No
Replace the malfunctioning part.
19
Is the engine compression correct?
Yes
Inspect the following:
• Valve timing
• Clutch
No
Inspect for cause.
20
Verify test results.
• If normal, return to diagnostic index to service any additional symptoms.
• If malfunction remains, replace PCM.