TROUBLESHOOTING GUIDE — 10 LOW IDLE SPEED/ROUGH IDLE — AFTER WARM-UP
F-34spec table10 LOW IDLE SPEED/ROUGH IDLE — AFTER WARM-UP
DESCRIPTION: Engine runs normally at idle during warm-up but vibrates excessively after warm-up.
NOTE
[TROUBLESHOOTING HINTS] (1) Idle speed control malfunction. (2) Air/Fuel mixture too lean: Air leakage of intake air system; Low fuel line pressure. (3) Air/Fuel mixture too rich: Fuel injection control malfunction (Correction for coolant temperature). (4) Poor ignition spark. (5) Low engine compression.
Troubleshooting steps 1-4
1
INSPECTIONCheck if '00' is displayed on Self-Diagnosis Checker with ignition switch ON — page F-78
RESULTYes
ACTIONGo to next step
1
INSPECTIONCheck if '00' is displayed on Self-Diagnosis Checker with ignition switch ON — page F-78
RESULTNo
ACTIONMalfunction Code No. displayed: Check for cause (Refer to specified check sequence) — page F-80. "88" flashes: Check ECU terminal 1F voltage — page F-128; Voltage: Approx. 12V (ignition switch ON); If OK, replace ECU — page F-127; If not OK, check wiring between ECU and Self-Diagnosis Checker — page F-7
2
INSPECTIONCheck switches for correct operation with Self-Diagnosis Checker Monitor Lamp and ignition switch ON — page F-89
RESULTYes
ACTIONGo to next step
2
INSPECTIONCheck switches for correct operation with Self-Diagnosis Checker Monitor Lamp and ignition switch ON — page F-89
RESULTNo
ACTIONLamp not ON/OFF with specified switch: Check for cause (Refer to specified check sequence) — page F-90. Lamp always ON: Check wiring between ECU terminal 1D and Self-Diagnosis Checker — page F-7
3
INSPECTIONDisconnect ISC valve connector at idle and check if "clicking" is heard from ISC valve
RESULTYes
ACTIONGo to next step
3
INSPECTIONDisconnect ISC valve connector at idle and check if "clicking" is heard from ISC valve
RESULTNo
ACTIONReplace ISC valve — page F-99
4
INSPECTIONCheck for correct intake manifold vacuum at idle; Vacuum: More than 450 mmHg (17.7 inHg)
RESULTYes
ACTIONGo to next step
4
INSPECTIONCheck for correct intake manifold vacuum at idle; Vacuum: More than 450 mmHg (17.7 inHg)
RESULTNo
ACTIONLow vacuum: Check for air leakage of intake air system components — page F-93
See also
F-78SELF-DIAGNOSIS FUNCTIONF-80SELF-DIAGNOSIS FUNCTIONF-128CONTROL SYSTEM - Engine Control Unit Terminal Voltage TableF-127CONTROL SYSTEM - Engine Control Unit InspectionF-7OUTLINE - WIRING DIAGRAMF-89SELF-DIAGNOSIS FUNCTIONF-90SELF-DIAGNOSIS FUNCTIONF-99IDLE SPEED CONTROL (ISC) SYSTEMF-93INTAKE AIR SYSTEM