Manual

24
Measurement Typical Readings Interpretation
Battery Volts 12.4 to 12.8 Volts C h e c k s b a t t e r y s t a t e o f c h a r g e .
(Engine Off) Below 12.3V, charge is low, or load may be on.
Ignition Energy More than 20 mVSec Shows that there is coil energy available to
(Cranking) start the engine.
Battery Volts 13.2 to 15.2 Volts Shows the voltage regulator setting and
(Engine Running) if the alternator functions.
Amps Ripple None If al ter nator has a bad diode o r stator,
(Engine Running) a message will appear.
Ignition Energy 35-55 mVSec Checks for faulty coils, and driver modules.
(Engine Running)
Dwell 60% w/ Ballast Adjust as necessary.
3 to 4 mSec, current limited Checks ignition modules.
Dwell Variation 3.0° or less Checks primary ignition system performance.
(Engine Running) Test from Idle to Cruise RPM.
Timing Variation 3.0° or less Shows ignition timing irregularity if too high.
(Engine Running)
Driver Voltage Electronic less than 1.5V Sh ow s co il dr i ver modu le, an d m odu le
(Engine Running) Points less than 0.3V ground resistance if too high.
Coil Oscillations Electronic 1 to 4 Osc Ch ecks fo r sho r ts i n coi l insu lat io n or
(Engine Running) Points 4 to 8 Osc connected components.
HARD
START
CHARGING
(Engine Running)
IGNITION
PRIMARY
Firing KV 8 to 15 KV Checks plug gaps and wire condition.
Burn Time, Live 0.8 to 2.3 mSec C h e c k s c o n d i t i o n o f s e c o n d a r y
ignition (Engine at Idle) system. Finds open or grounded spark
plug wires.
Burn Time, Minimum More than 0.8 mSec Shows wor n or wide gap pl ugs, breaks
(Accelerate Engine) in spark plug wires, or lean fuel, if less.
Burn Time, Maximum Uniform among cylinders Finds fouled or grounded plugs or wires.
(Accelerate Engine) Locates ignition misfires. Rich fuel mix.
Cranking Volts Not less than 9.6 volts. Che cks ba t t er y an d s t ar te r c o n diti o n ,
performance.
Cranking Amps 100 to 300 Amps High amps, possible bad starter.
Low amps, possible bad connections,
or bad battery.
Cranking RPM Over 150 RPM Checks starter performance.
Alternator Amps 50 to 100 Amps Compare alternator output to specs.
Battery CCA est. 500 to 1000 CCA If lower than the rating on the batter y,
Compare to Battery the b atter y is we ak an d m ay be read y
Specs. for replacement.
Amps Peak Less than 5 percent P r o b a b l y l o w c o m p r e s s i o n , i f m o r e
than 8%.
Power Difference All cylinders should be If one or more cylinders are high, compare
per Cylinder less than 5. t o t h e E l e c t r o n i c C o m p r e s s i o n a n d
Secondary tests.
%RPM drop when 5 to 15% uniform Th e h i g h e r th e n u m be r t h e s t r on g e r
each cylinder is the cyli nder. A negative number means
shut off the speed increased.
Typical Readings - Distributor
The readings listed here are typical for many common engines, but should be compared to the manufacturer's
specifications before extensive repair work is undertaken.
IGNITION
SECONDARY
STARTING / CHARGING
HISTORY
POWER
BAL & CONT.