|
|
|
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS TSB Revision MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE> 13B-199 • 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 75 Hz Judgment Criteria • Long-term fuel trim has continued to be higher or • Short-term fuel trim has continued to be higher Check Area • 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 75 Hz Judgment Criteria • Long-term fuel trim has continued to be higher or • Short-term fuel trim has continued to be higher Check Area • Under the closed loop air/fuel ratio control. • The right bank heated oxygen sensor (front) is 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 (Number 1, 3, 5) failed. • Incorrect fuel pressure • Air drawn in from gaps in gasket, seals, etc. • Right bank heated oxygen sensor failed. • Engine coolant temperature sensor failed. • Intake air temperature sensor failed. • Barometric pressure sensor failed. • Use of incorrect or contaminated fuel. • ECM failed. <M/T> • PCM failed. <A/T> 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? |