Suzuki GRAND VITARA Owner's Manual page 108

1A-53 Engine General Information and Diagnosis:
Condition
Surge – Engine power
variation under steady
throttle or cruise. Feels
like vehicle speeds up
and down with no change
in accelerator pedal
Excessive detonation –
Engine makes
continuously sharp
metallic knocks that
change with throttle
opening. Sounds like pop
corn popping
Possible cause
Leaky or loosely connected high-tension
cord (for M16 engine)
Faulty spark plug (excess carbon
deposits, improper gap, burned
electrodes, etc.)
Variable fuel pressure
Kinky or damaged fuel hose and lines
Faulty fuel pump (clogged fuel filter)
Malfunctioning EGR valve
Poor performance of MAF sensor
Faulty fuel injector
Faulty ECM
Faulty electric throttle body assembly
Faulty accelerator pedal position (APP)
sensor assembly
Faulty spark plug
Loose connection of high-tension cord
(for M16 engine)
Engine overheating
Clogged fuel filter (faulty fuel pump) or
fuel lines
Air drawn in through intake manifold or
throttle body gasket
Malfunctioning EGR valve
Poor performance of knock sensor, ECT
sensor or MAF sensor
Faulty fuel injector(s)
Faulty ECM
Excessive combustion chamber
deposits
Camshaft position control (VVT) system
out of order (for M16 engine)
Correction / Reference Item
"High-Tension Cord Removal and Installation
(For M16 Engine): in Section 1H"
"Spark Plug Inspection: in Section 1H"
"Fuel Pressure Check: "
"EGR Valve Inspection: in Section 1B"
"Mass Air Flow (MAF) and Intake Air
Temperature (IAT) Sensor Inspection: in
Section 1C"
"Fuel Injector Circuit Check: "
"Electric Throttle Body Assembly On-Vehicle
Inspection: in Section 1C"
"Accelerator Pedal Position (APP) Sensor
Assembly Inspection: in Section 1C"
"Spark Plug Inspection: in Section 1H"
"High-Tension Cord Removal and Installation
(For M16 Engine): in Section 1H"
Condition "Engine overheating"
"Fuel Pressure Check: " or "Fuel Pump and Its
Circuit Check: "
"EGR Valve Inspection: in Section 1B"
"DTC P0327 / P0328: Knock Sensor Circuit
Low / High: ", "Engine Coolant Temperature
(ECT) Sensor Inspection: in Section 1C" or
"Mass Air Flow (MAF) and Intake Air
Temperature (IAT) Sensor Inspection: in
Section 1C"
"Fuel Injector Circuit Check: "
"Pistons, Piston Rings, Connecting Rods and
Cylinders Inspection and Cleaning: For J20
Engine in Section 1D" or "Cylinders, Pistons
and Piston Rings Inspection: For M16A Engine
with VVT in Section 1D" and/or "Piston Pins
and Connecting Rods Inspection: For M16A
Engine with VVT in Section 1D"
"Oil Control Valve Inspection: For M16A
Engine with VVT in Section 1D"