MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-574
STEP 10. Check the fuel pressure.
.
Q: Is the fuel pressure normal?
YES :
Go to Step 11.
NO :
Repair or replace. Then confirm that the malfunction
symptom is eliminated.
STEP 11. Using scan tool MB991502, check data list.
CAUTION
To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Check the following items in the data list. Refer to, Data List
Reference Table
a. Item 45: Idle Air Control Motor Position.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the actuator operating properly?
YES :
Check the following items, and repair or replace the
defective items.
a. Vacuum leak.
•
Broken intake manifold gasket.
•
Broken air intake hose.
•
Broken vacuum hose.
•
Positive crankcase ventilation valve does
not operate.
b. Injector clogged.
Then confirm that the malfunction symptom is
eliminated.
NO :
Adjusting the basic idle speed. Refer to, Basic Idle
Speed Adjustment
STEP 12. Check the ignition timing.
Refer to GROUP 11C, On-vehicle Service
−
Ignition Timing
Check
.
Q: Is the ignition timing normal?
YES :
Check the following items, and repair or replace the
defective items.
a. Check the ignition coil, spark plugs, spark plug
cables.
b. Check if the injectors are clogged.
c. Check compression pressure.
d. Check if the foreign materials (water,
kerosene, etc.) got into fuel.
Then confirm that the malfunction symptom is
eliminated.
NO :
Check that the crankshaft position sensor and timing
cover are in the correct position. Then confirm that the
malfunction symptom is eliminated.
AKX01177
16 PIN
MB991502
AB
