Engine Diagnosis Table - Suzuki Grand Vitara XL-7 Service Manual

6-20 ENGINE DIAGNOSIS (RHZ ENGINE WITH SINGLE-CONNECTOR ECM)

ENGINE DIAGNOSIS TABLE

Perform troubleshooting referring to following table when ECM (PCM) has detected no DTC and no abnormality
has been found in visual inspection and engine basic inspection previously.
Condition
Hard starting
(Engine cranks OK)
Possible Cause
Fuel system out of order.
D Lack of fuel in fuel tank
D Fuel filter
– Dirty or clogged
– Water mixed in
D Dirty or clogged fuel hose or pipe
D Fuel injection pipe
– Cracks
– Fuel leakage from joints
D Clogged fuel injector
D Faulty fuel pump
Engine and emission control system
out of order.
D Faulty ECM
D Faulty fuel pressure sensor
D Faulty CKP sensor (Engine speed sensor)
D Faulty CMP sensor
D Faulty fuel injection pump
– Air mixed in
– Pump internal damage
– Faulty fuel pressure regulator
D Faulty fuel injector
D Faulty ECT sensor
Glow system out of order.
D Faulty glow plug
D Faulty pre post heating relay
Low compression.
D Compression leak from valve seat
D Sticky valve stem
D Weak or damaged valve springs
D Compression leak at cylinder head
gasket
D Sticking or damaged piston ring
D Worn piston, ring or cylinder
Immobilizer control system out of order.
Others
D Broken valve timing belt
D Faulty EGR throttle valve
Reference Item
Refill.
Replace.
Repair.
Clean.
Replace.
Correct.
Replace.
Inspect and replace.
Replace.
Inspect and replace.
Inspect and replace.
Inspect, adjust and replace.
Refill fuel in fuel tank.
Replace.
Inspect and replace.
Inspect and replace.
Inspect and replace.
Inspect and replace.
Inspect and replace.
Remove cylinder head and lap
valves.
Correct or replace valve.
Replace valve springs.
Repair or replace.
Replace piston rings.
Replace ring and piston. Rebore or
replace cylinder.
Refer to Section 8G.
Replace timing belt and repair valve
train.
Inspect and replace.