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

id0103008017b2

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 the 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 the 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 (Unleaded gasoline model)
• 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 the MAF sensor, TP sensor and VSS
• ATX malfunction (ATX)
• Clutch slippage (MTX)
• 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 [LF, L3].)
(See AFTER REPAIR PROCEDURE [LF, L3].)
Caution
• Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and the 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

1
Inspect for the following:
• Vacuum connection
• Air cleaner element
• No air leakage from the intake-air system
• No restriction of the intake-air system
• Proper sealing of the intake manifold and components attached to the intake manifold: such as the EGR valve, the 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 a stall condition exists a retrieve continuous memory and KOEO DTCs.
Are any DTCs displayed?
Yes

DTC is displayed:

Go to the appropriate DTC test.
No

No DTC is displayed:

Go to the next step.
3
Is engine overheating?
Yes
Go to the 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.
Monitor the PIDs while driving the vehicle.
Are the PIDs within the specifications?
Yes
Go to the next step.
No

RPM PID:

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

VPWR PID:

Inspect for an intermittently open circuit.

MAF PID:

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

TP PID:

Inspect if the output signal from the TP sensor changes smoothly.

VSS PID:

Inspect for intermittently open circuit of the VSS and the related wire harness.
5
Visually inspect the CKP sensor and the teeth of the crankshaft pulley.
Are the CKP sensor and the teeth of the crankshaft pulley normal?
Yes
Go to the next step.
No
Replace the malfunctioning parts.
6
Measure the gap between the CKP sensor and the 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 spark plugs.
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 a clogged fuel injector.
No
Install the spark plugs on the 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 throttle lever is resting on throttle valve stop screw and/or throttle valve orifice plug.
Is the lever in the 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 fuel pipe and fuel distributor.
Connect a jumper wire between the F/P terminal at the check connector in main fuse block and ground.
Turn the ignition switch to ON position.
Is fuel line pressure correct with the ignition switch to ON position?
Yes
Go to the next step.
No

Zero or low:

Inspect for a 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 the fuel line.
Service if necessary.
Does fuel line pressure hold 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 fuel pump unit.
13
Note
• The following test is for engines stalling with the A/C on. If other symptoms exist, go to the next step.
Connect a pressure gauge to the A/C low and high pressure side lines.
Turn the A/C on and measure the low side and high side pressures.
Are the pressures 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 the 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 parts.
15
Disconnect the vacuum hose between the purge solenoid valve and the intake manifold from the purge solenoid valve side.
Plug the open end of the 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 the 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 parts.
17
Inspect the VTCS operation.
Is the VTCS normal?
Yes
Go to the next step. (Unleaded gasoline model)
Go to Step 19. (Leaded gasoline model)
No
Replace or replace the malfunctioning parts.
18
Inspect EGR system.
Is the EGR system normal?
Yes
Go to the next step.
No
Replace the malfunctioning parts.
19
Is the engine compression correct?
Yes
Inspect the following:
• Valve timing
• Internal transaxle part (ATX)
• Clutch (MTX)
No
Inspect for the cause.
20
Verify the test results.
• If normal, return to the diagnostic index to service any additional symptoms.
• If the malfunction remains, replace the PCM.