General Technologies TA500 SmarTach+COP : Multisystem Engine Analyser - Manual (Page 5)

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4- Select the measurement to show in the main display: RPM, spark burn time or
spark KVolt.
5- Select the mode for the secondary display: Minimum and Maximum of the main display
or the complementary measurements.
6- Place the capacitive pick-up (yellow tip of the probe), as shown in Fig. 4 below, over
one of the ignition modules, searching for the position that produces a stable RPM or
spark burn time reading.
7- If this is the first measurement taken in the engine, then proceed to calibrate the spark
KVolt measurement first (following the procedure in ‘3.3.4 Main Function / Calibrate
button‘), as this calibration value will be used as a reference value to compare the
spark KVolt reading between all the coil on plug or coil near plug modules.
8- Place the capacitive pick-up over the ignition modules and read the measurements
in the display.
Fig. 4 - Capacitive pickup on coil on plug module
Coil on Plug module
Capacitive pickup
Important:
• In some engines, the ignition modules are located very close together, and this may
cause the TA500’s capacitive pick-up to receive signals from nearby modules, which
may cause false readings.
• To reduce interference from others ignition modules, cover completely the nearby
ignitions modules with pieces of aluminum foil, making sure the aluminum foil is
connected to a good electrical ground in the engine (e.g. valves cover, mounting
bolts).
CAUTION
To avoid personal injuries and damage to the instrument carefully inspect the
spark plug wires, distributor cap, ignition coil , ignition module, and all other
ignition system parts for damage or leaks, and avoid using this instrument in
case any damage or leaks are found. Never touch the capacitive pick-up or
flexible probe during a test. Wear insulating gloves when working around high
voltage, and hot parts, and keep away from moving parts (fan, drive belts, etc)
and hot objects (exhaust manifold and pipes, muffler, catalytic converter, etc.)
Nearby ignition coils shielded
with aluminum foil
Ignition coil under test
Probe
Fig. 5 - Avoiding interference by shielding nearby ignition coils
3.4 Measurement Procedures
3.4.1 TA500 measuring functions
The TA500 has specially dedicated modes for use in the diagnostics and
troubleshooting of Coil on Plug and Coil near Plug ignition technology, and for systems
using spark plug wires. These special modes compensates for differences in signal strength
and waveform patterns between ignition systems.
The TA500 can measure the following:
• Engine RPM,
• Spark burn time, and
• Spark KVolt (relative measurement).
3.4.1.1 Engine RPM
Measures engine RPM in 2, 4 cycles and DIS engines, and it can be used in
combination with spark burn time and spark KVolt measurements, to evaluate the ignition system
performance at different engine speeds.
3.4.1.2 Spark burn (firing) time
The spark burn time, also called “firing time”, is the measurement of the time period from
the moment that a spark is initiated up to the point when it is extinguished, and is the most
indicative measurement of performance of the ignition system. Abnormally long or short
burn times may indicate some problem in the ignition module, spark plug, fuel mixture,
cylinder compression, etc.
3.4.1.2 Spark KVolt
Spark KVolt values are relative measurements, useful to compare the performance of the
ignition system in each cylinder. Comparing spark KVolt between cylinders may be used
to diagnose common problems like misfires, broken spark plug wires, etc. However spark
KVolt values may vary widely, are less consistent and not always indicative of a properly
working ignition system.
3.4.2 Measuring Coil on Plug and Coil near Plug ignition systems
1- Turn the instrument on.
2- If not already in
COP mode, select it by pressing the ‘Ignition System’ button.
3- Select the number of cycles for the engine under measurement by pressing the ‘Engine
Cycles’ button repeatedly until the display shows the correct setting.