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Section 2: Testing
WARNING:
+ Use caution working around the ignition coil, distributor cap, ignition wires,
and spark plugs. These components have high voltage when the engine is
running.
+ Electrical shock may occur if you disconnect or connect secondary wires
while the engine is running.
2-1 Spark Event Test Procedure
. Attach Pickup clamp
You may want to draw a picture of the engine and spark piug wires show-
ing the order in which you will be testing.
Connect the Pickup Clamp (blue) to the first plug
wire near the spark plug. To ensure accurate
readings keep clamp at least 1-2 inches from other
ignition cables and metallic engine parts. See the
illustration for an example.
Ground the tester
Connect Ground Clamp (black) to a good vehicle ground or the battery's
negative terminal. A good ground is required for Pickup Clamp's harness
shield. If this is not properly grounded noise may cause misleading data
to be received.
Turn tester ON
Press the ON/OFF button. If the tester does turn on make sure it has a
good 9V battery.
Select Distributor or DIS
Select P=DISTRIB. for testing on vehicles with distributors or press
T=DIS for distributorless vehicies.
Start Engine
Start engine and let idle. Allow engine to warm-up and the idle to stabilize
before monitoring and recording readings.
Take readings
Record the Peak Kv, Burn Kv and Burn Time real time readings.
Next Cylinder
Connect the Pickup Clamp (blue) to the next cylinder's wire to be tested.
Refer to the drawing you made indicating test order. Remember
to keep
clamp at least 1-2 inches from other ignition cables and metallic engine parts,
to ensure accurate readings.
Repeat steps 5 and 6 until all cylinders have been tested
Compare readings
Refer to the different measurement sections for test results explanations.
©
Peak Kv Measurements
Peak Kv is the secondary ignition voltage it took to
initiate the spark event. Because this voltage is in
the thousands it is referred to as Kv (Kilovolts).
Differences in Peak Kv readings can be caused by
problems with the following areas: plug wires &
plugs, cap, rotor, coil/s, ignition timing, air/fuel
mixture, cylinder compression.
When testing a DIS vehicle, consideration must be
given to cylinder firing polarity. Most DIS ignition
systems use coils that connect two secondary wires and plugs. This type of
ignition coil setup will fire one plug conventionally (negative). The other plug
connected to the same coil will fire inverted (positive). Their may be a notice-
able difference, as much as 6 Kv, in Peak Kv readings from conventional to
inverted. This is normal. To avoid being mislead, only compare similar firing
types readings to each other when testing on DIS systems.
0 Kv
NOTE: Some engine applications use two spark plugs per
engine cylinder. The secondary plugs may not be used at
all times.
if voltage measurements, on the same type of firing plugs, varies by more than
about 5Kv, a problem may exist in ignition circuit or it's components.
See the Table 1 below for test result meanings.
+ None - Functioning properly
All like readings
within approx. 5Kv
No firing voltage
all cylinders
+ No power to ignition coil/s + Bad ignition coil/s
* Ignition Module/Powertrain controller failure
e Crank / Cam sensor failure
+ Shorted plug wire/s
* Shorted coil secondary
* Cylinder compression low
+ Plug gap to small
e Fuel mixture too rich
œ Ignition timing overly retard
* Fouled spark plug
* Shorted spark plug
Lower secondary
Kv on one or more
cylinders
Open plug wire/s
+ Degraded spark plug/s
Plug gap to big
+ Ignition timing overly advanced
Fuel mixture to lean (may also cause misfires)
Higher secondary
Kv on one or
more cylinders
Fuel distribution problems + Vacuum leak
Bent or worn out shaft bushings in the distributor
Loose rotor or distributor cap
Moisture inside distributor cap
Multiple ignition related problems (such as those
listed for Low and High Kv)
Uneven secondary
Kv on all cylinders
Table 1
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