Suzuki Engine 2002 GRAND VITARA SQ420 Service Manual page 178

Condition
Engine hesitates Ignition System out of order.
(Momentary lack of
• Spark plug faulty or plug gap as out of
response as the
accelerator is
Fuel system out of order.
depressed. Can
• Fuel pressure out of specification
occur at all vehicle
speeds. Usually
most severe when
• Clogged fuel filter, hose or pipe
first trying to make
Engine overheating
the vehicle move,
Engine and emission control system out of
as from a stop
order.
sign.)
• Faulty EGR system
• Faulty injector
• Faulty TP sensor, ECT sensor or MAF
• Faulty ECM (PCM)
Low compression
Surges Ignition system out of order.
(Engine power
• Defective spark plug (excess carbon
variation under
steady throttle or
cruise. Feels like
Fuel system out of order.
the vehicle speeds
• Variable fuel pressure
up and down with
no change in the
accelerator pedal.)
Engine and emission control system out of
order.
• Faulty EGR system
• Faulty MAF sensor
• Faulty injector
• Faulty ECM (PCM)
Possible Cause
adjustment
– Clogged fuel filter
– Faulty fuel pressure regulator
sensor
deposits, improper gap, and burned
electrodes, etc.)
– Clogged fuel filter
– Kinky or damaged fuel hose and line
– Faulty fuel pressure regulator
ENGINE GENERAL INFORMATION AND DIAGNOSIS (H25 ENGINE) 6-1-37
"Spark Plugs" in Section 6F2.
"Diag. Flow Table B-3" in this section.
Refer to "Overheating" in this table.
"DTC P0440 Diag. Flow Table" in this sec-
tion.
"Fuel Injector" in Section 6E2.
"TP Sensor", "ECT Sensor" or "MAF Sen-
sor" in Section 6E2.
"Inspection of ECM (PCM) and Its Circuit" in
this section.
Previously outlined.
"Spark Plugs" in Section 6F2.
"Diag. Flow Table B-3" in this section.
"DTC P0400 Diag. Flow Table" in this sec-
tion.
"MAF Sensor" in Section 6E2.
"Fuel Injector" in Section 6E2.
"Inspection of ECM (PCM) and Its Circuit" in
this section.
Correction