TROUBLESHOOTING GUIDE

F-47prose procedure

Troubleshooting Guide (steps 6–12)

STEP	INSPECTION	RESULT	ACTION
6	Check if throttle linkage is correctly installed and operates freely	Yes	Go to next step
6	Check if throttle linkage is correctly installed and operates freely	No	Correct, repair, or replace as required any binding or damaged linkage and adjust cable deflection at throttle body (page F-96)
7	Check for correct intake manifold vacuum at idle Vacuum: More than about 450 mmHg (17.7 inHg)	Yes	Go to next step
7	Check for correct intake manifold vacuum at idle Vacuum: More than about 450 mmHg (17.7 inHg)	No	Check for air leakage of intake air system components (page F-93)
8	Check if air cleaner element is clean (page F-75)	Yes	Go to next step
8	Check if air cleaner element is clean (page F-75)	No	Replace air cleaner element (page F-92)
9	Check for correct ignition timing at idle (page F-76) Ignition timing: 10° ± 1° BTDC	Yes	Check if ignition timing advances when accelerating - If advances, go to next step - If no advance, replace ECU (page F-127)
9	Check for correct ignition timing at idle (page F-76) Ignition timing: 10° ± 1° BTDC	No	Adjust (page F-76)
10	Check for correct fuel line pressure at idle (page F-103) Fuel line pressure: 265—314 kPa (2.7—3.2 kg/cm², 38—46 psi) (Vacuum hose to pressure regulator disconnected)	Yes	Check if fuel line pressure decreases when accelerating quickly - If decreases, check fuel pump maximum pressure (page F-108) - If OK, check fuel line and filter for clogging - If not clogged, go to next step
10	Check for correct fuel line pressure at idle (page F-103) Fuel line pressure: 265—314 kPa (2.7—3.2 kg/cm², 38—46 psi) (Vacuum hose to pressure regulator disconnected)	No	Low pressure Check for fuel line pressure while pinching fuel return hose - If fuel line pressure quickly increases, check pressure regulator (page F-111) - If fuel line pressure gradually increases, check for clogging between fuel pump and pressure regulator - If not clogged, check fuel pump maximum pressure (page F-108) High pressure Check if fuel return line is clogged - If OK, replace pressure regulator (page F-112) - If not OK, replace
11	Check for correct engine compression (page B-10) Engine compression: 1,324—932 kPa (13.5—9.5 kg/cm², 192—135 psi) - 300 rpm	Yes	Go to next step
11	Check for correct engine compression (page B-10) Engine compression: 1,324—932 kPa (13.5—9.5 kg/cm², 192—135 psi) - 300 rpm	No	Check engine condition - Worn piston, piston rings or cylinder wall - Defective cylinder head gasket - Distorted cylinder head - Improper valve seating - Valve sticking in guide (page B-10)
12	Try known good ECU and check if condition improves (page F-127)

INSPECTIONCheck if throttle linkage is correctly installed and operates freely

RESULTYes

ACTIONGo to next step

INSPECTIONCheck if throttle linkage is correctly installed and operates freely

RESULTNo

ACTIONCorrect, repair, or replace as required any binding or damaged linkage and adjust cable deflection at throttle body (page F-96)

INSPECTIONCheck for correct intake manifold vacuum at idle Vacuum: More than about 450 mmHg (17.7 inHg)

RESULTYes

ACTIONGo to next step

INSPECTIONCheck for correct intake manifold vacuum at idle Vacuum: More than about 450 mmHg (17.7 inHg)

RESULTNo

ACTIONCheck for air leakage of intake air system components (page F-93)

INSPECTIONCheck if air cleaner element is clean (page F-75)

RESULTYes

ACTIONGo to next step

INSPECTIONCheck if air cleaner element is clean (page F-75)

RESULTNo

ACTIONReplace air cleaner element (page F-92)

INSPECTIONCheck for correct ignition timing at idle (page F-76) Ignition timing: 10° ± 1° BTDC

RESULTYes

ACTIONCheck if ignition timing advances when accelerating - If advances, go to next step - If no advance, replace ECU (page F-127)

INSPECTIONCheck for correct ignition timing at idle (page F-76) Ignition timing: 10° ± 1° BTDC

RESULTNo

ACTIONAdjust (page F-76)

INSPECTIONCheck for correct fuel line pressure at idle (page F-103) Fuel line pressure: 265—314 kPa (2.7—3.2 kg/cm², 38—46 psi) (Vacuum hose to pressure regulator disconnected)

RESULTYes

ACTIONCheck if fuel line pressure decreases when accelerating quickly - If decreases, check fuel pump maximum pressure (page F-108) - If OK, check fuel line and filter for clogging - If not clogged, go to next step

INSPECTIONCheck for correct fuel line pressure at idle (page F-103) Fuel line pressure: 265—314 kPa (2.7—3.2 kg/cm², 38—46 psi) (Vacuum hose to pressure regulator disconnected)

RESULTNo

ACTIONLow pressure Check for fuel line pressure while pinching fuel return hose - If fuel line pressure quickly increases, check pressure regulator (page F-111) - If fuel line pressure gradually increases, check for clogging between fuel pump and pressure regulator - If not clogged, check fuel pump maximum pressure (page F-108) High pressure Check if fuel return line is clogged - If OK, replace pressure regulator (page F-112) - If not OK, replace

INSPECTIONCheck for correct engine compression (page B-10) Engine compression: 1,324—932 kPa (13.5—9.5 kg/cm², 192—135 psi) - 300 rpm

RESULTYes

ACTIONGo to next step

INSPECTIONCheck for correct engine compression (page B-10) Engine compression: 1,324—932 kPa (13.5—9.5 kg/cm², 192—135 psi) - 300 rpm

RESULTNo

ACTIONCheck engine condition - Worn piston, piston rings or cylinder wall - Defective cylinder head gasket - Distorted cylinder head - Improper valve seating - Valve sticking in guide (page B-10)

INSPECTIONTry known good ECU and check if condition improves (page F-127)

RESULT

ACTION

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TROUBLESHOOTING GUIDE

Troubleshooting Guide (steps 6–12)

See also

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