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MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS TSB Revision MULTIPORT FUEL INJECTION (MFI) <2.4L> 13A-145 • Intake air temperature is higher than 60 ° C (140 °
F) when the engine is started. • Under the closed loop air/fuel ratio control. • Intake air temperature is higher than -10 ° C (14 ° F). • Barometric pressure is higher than 76kPa (11 • Volume air flow sensor output frequency is 88 Hz Judgment Criteria • Long-term fuel trim has continued to be higher or • Short-term fuel trim has continued to be higher Check Conditions • Engine coolant temperature is higher than ° C (212 ° F) when the engine is started. • Intake air temperature is higher than 60 ° C (140 °
F) when the engine is started. • Under the closed loop air/fuel ratio control. • Intake air temperature is higher than -10 ° C (14 ° F). • Barometric pressure is higher than 76kPa (11 • Volume air flow sensor output frequency is 88 Hz Judgment Criteria • Long-term fuel trim has continued to be higher or • Short-term fuel trim has continued to be higher Check Conditions • Under the closed loop air/fuel ratio control. • The heated oxygen sensor (front) is active. Judgment Criteria • Long-term fuel trim has continued to be higher or • Short-term fuel trim has continued to be higher TROUBLESHOOTING HINTS (The most likely • Volume air flow sensor failed. • Injector failed. • Incorrect fuel pressure • Air drawn in from gaps in gasket, seals, etc. • Heated oxygen sensor failed. • Engine coolant temperature sensor failed. • Intake air temperature sensor failed. • Barometric pressure sensor failed. • Use of incorrect or contaminated fuel. • PCM failed. DIAGNOSIS Required Special Tools STEP 1. Check the exhaust leaks. Q: Are there any abnormalities? YES : Go to Step 2. STEP 2. Check the intake system vacuum leak. Q: Are there any abnormalities? |