Suzuki 2000 Grand Vitara SQ416, Service Manual

Page: 641 / 729

YH4
GRAND
VITARA
IGNITION SYSTEM (FOR G16 ENGINE) 6F1-5
1. Injector coupler
CMP sensor signal
Ignition trigger
signal
Primary coil
current flow time
Waveforms at specified idle speed
Oscilloscope waveforms
STEP ACTION YES NO
10 Ignition Timing Check
1) Check initial ignition timing and ignition timing
advance, referring to “Ignition Timing Check” in
this section.
Is check result satisfactory?
System is in good
condition. Adjust ignition timing
if adjustable or check
CMP sensor, signal
rotor (camshaft
looseness), crank-
shaft pulley / timing
belt cover installation
and input signals
related to ignition
system.
Reference
Oscilloscope waveforms of CMP sensor and ignition trigger signal
are as shown in figure when connecting oscilloscope between ter-
minals C51-2-26 and C51-3-26 of ECM (PCM) connectors con-
nected to ECM (PCM), and between terminal C51-2-24 and
ground.
IGNITION SPARK CHECK
1) Disconnect injector coupler.
WARNING:
Without disconnection of injector coupler, combustible
gas may come out from spark plug holes during this test
and may get ignited in engine room.
2) Remove spark plug and check it for condition and type, referring
to “Spark Plug” under “On-Vehicle Service” later in this section.
3) If OK, connect ignition coil coupler to ignition coil assembly and
connect spark plug to ignition coil assembly or high-tension
cord. Ground spark plug.
4) Crank engine and check if each spark plug sparks.
If no spark is emitted, inspect the related parts as described un-
der ”Diagnosis” earlier in this section.
6) After checking, install spark plug and ignition coil, referring to
“Spark Plug” and “Ignition Coil Assembly” under “On-Vehicle
Service” later in this section.
7) Connect injector coupler.