6-1-34 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
Poor gasoline mileage
Faulty spark plug (improper gap, heavy depos-
its, and burned electrodes, etc.)Spark plugs in Section 6F2.
Fuel pressure out of specification “DIAG. FLOW TABLE B-3” in this
section.
Faulty TP sensor, ECT sensor or MAF sensor TP sensor, ECT sensor or MAF
sensor in Section 6E2.
Faulty EGR system “DTC P0400 DIAG. FLOW TABLE”
in this section.
Faulty injector Fuel injector in Section 6E2.
Faulty ECM (PCM) Inspection of ECM (PCM) and its
circuit in this section.
Low compression Refer to the same item in “HARD
STARTING” of this table.
Poor valve seating Valves inspection in Section 6A2.
Dragging brakes Diagnosis in Section 5.
Slipping clutch Diagnosis in Section 7C1.
Thermostat out of order Thermostat in Section 6B.
Improper tire pressure Diagnosis in Section 3.
Excessive engine oil
consumptionSticky piston ring Piston cleaning in Section 6A2.
Worn piston and cylinder Cylinders, pistons and piston rings
inspection in Section 6A2.
Worn piston ring groove and ring Pistons and piston rings inspection
in Section 6A2.
Improper location of piston ring gap Pistons installation in Section 6A2.
Worn or damaged valve stem seal Valves and cylinder head in Sec-
tion 6A2.
Worn valve stem Valves inspection in Section 6A2.
Low oil pressure
Improper oil viscosity Engine oil and oil filter change in
Section 0B.
Malfunctioning oil pressure switch Oil pressure switch inspection in
Section 8.
Clogged oil strainer Oil pan and oil pump strainer clean-
ing in Section 6A2.
Functional deterioration of oil pump Oil pump in Section 6A2.
Worn oil pump relief valve Oil pump in Section 6A2.
Excessive clearance in various sliding parts “INSPECTION” for each parts in
Section 6A2. Condition Possible Cause Correction
