ATI Technologies SmartTachSmartTach, User Manual

Page: 92 / 110

TROUBLESHOOTING
Page 6-6 SmartTach Operating Manual
Common Faults And Configuration Errors
Improper Setting of Input Conditioning Select (06)
This may result in erratic or no measurement. Verify that parameter 06 is
set to the proper signal type.
Improper Setting of Spark Input Threshold Level (10)
This may result in erratic or no measurement. In general, a setting of 2
volts should be adequate when using an Inductive Pickup Sensor. Please
refer to the information in chapter 4 for details. When connecting the
input directly to the coil negative terminal, this parameter value should be
raised to 4 volts. A low setting in this case may result in erratic readings.
Improper Input Polarity Setting (21)
The Intelligent Signal Conditioning circuitry can automatically configure
the inputs for all types of sensor signals (zero-crossing, 5V, 12V etc.).
However, it is impossible to automatically determine the correct trigger
edge of the signal to use. Improper settings of these parameters may
result in incorrect measurements. The polarity should always be set to
edge of the signal which has the greatest slope (either positive or
negative).
Incorrect Setting of Patterns/Pulses per Cam Rev (02)
The default value of this parameter is 1. When using engine starter ring-
gear (flywheel) teeth or an encoder type signal, be sure to set this
parameter to the number of teeth on the wheel. An incorrect setting will
result in incorrect measurement values without any other indications of
improper operation.
Cables Routed near Spark Plug Wires or Coils
All SmartTach cables should be routed away from all spark plug wire
cables and ignition coils. Even though the cables are shielded, high
frequency noise from the ignition system can penetrate into the inputs.
This will result in erratic operation.
Bad Connections in Wiring Cables
It is always better to spend extra time to insure that all connections are
properly made, especially when making custom cables. Loose
connections, especially in the ground/common lines will result in problems
which are very difficult to trace. This will almost always result in erratic
operation.