Isuzu 2008MY N Series, Руководство по ремонту

Страница: 358 / 404

Engine Control System (4HK1) 1A-355
Surges
Checks Action
Difinition:
The engine has a power variation under a steady throttle or cruise. The vehicle seems to speed up and slow down
with no change in the accelerator pedal.
Preliminary Checks • Diagnostic System Check - Engine Controls.
• Ensure the driver understands the A/C compressor operation.
• Use the scan tool in order to make sure the Vehicle Speed parameter
reading matches the vehicle speedometer.
• Inspect the ECM grounds for being clean, tight, and in their proper
locations.
• Inspect that the harness connectors are correctly connected.
• Inspect the fuel type and quality.
• Inspect the programmed fuel injector ID code for each cylinder.
• Inspect the Scan Tool Data List in this section.
• Inspect the Service Bulletin.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the
Scan Tool Data List in this section.
• Observe the Mass Air Flow (MAF) parameter for a skewed or slow MAF
sensor.
• Observe the Fuel Rail Pressure (FRP) Sensor parameter with the engine
OFF. The FRP Sensor should read 0.9 to 1.0 volt with the ignition switch
ON and engine OFF after the engine has stopped running for a minimum of
1 minute. If not, check for high resistance in each circuit or for a skewed
sensor.
• Observe the Fuel Rail Pressure and Desired Fuel Rail Pressure parameter
between idle and W.O.T. (accelerator pedal full travel) in Neutral. Fuel Rail
Pressure parameter should follow within
±
5 MPa (
±
725 psi) quick enough.
• Observe the Accelerator Pedal Position (APP). APP parameter should
change linearly from 0 to 100% according to the accelerator pedal
operation.
Fuel System Checks Inspect the fuel system for the following conditions. Refer to Fuel System
Check chart and appropriate procedure in Section 1D Engine Fuel.
• Air in the fuel system.
• Water contamination in the fuel.
• Fuel waxing or icing.
• Fuel filter clogging.
• Fuel leak off from the fuel pressure limiter valve and fuel injectors.
• Fuel lines between the fuel tank and fuel supply pump for being crushed,
kinked, tightness, cracks and plugged.
• A plugged fuel tank vent hose.
• Inside the fuel tank for any foreign material that may be getting drawn into
the fuel line pickup causing a blocked condition.
• Fuel supply pump operation.
Notice: The fuel supply pump must be timed to the engine and adjustment
value must be learned to the ECM.
• Perform the Cylinder Balance Test with a scan tool.
• Perform the Injector Force Drive with a scan tool.
LG4HKED-WE-0871.book 355 ページ ２００７年１１月２９日 木曜日 午後６時２９分