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Introduction
The DT-43KL is Digatron’s small, easy to use, digital engine monitoring system. This instrument was designed for the customer who
wants to know how their engine is functioning without spending a lot of time and money. This instrument monitors exhaust gas
temperature (EGT), with backlight and limit to warn you of possible engine problems.
About Exhaust Gas Temperature
Exhaust gas temperature is used primarily for adjusting the air/fuel ratio. Because of its quick response, the effects of carburetor
adjustments are seen immediately. Fuel system and carburetor problems can often be spotted quickly enough to prevent engine
damage.
Exhaust gas temperatures typically run between 1100°F and 1350°F. The EGT on a properly tuned engine will increase rapidly as the
throttle is opened and as the load on the engine is increased. At full throttle and full load the EGT will stabilize at a temperature
dependent on the air/fuel ratio. Both a “too lean” or a “too rich” condition will be indicated by a lower than peak temperature. The
“too lean” condition can damage your engine. An increase in coolant temperature or cylinder head temperature is usually an indication
of this. The best way to determine what temperature is normal for your motor is to tune for good plug or piston color and then observe
the temperature at various throttle settings.
Installing Your EGT Sensor
Our standard EGT sensor is a type K thermocouple temperature sensor. Install the sensor clamp assembly, or weld on, to the exhaust
header. Position the clamp so that the sensor will be in the center of the header. Contact your engine builder for the distance from the
exhaust flange. Using the fitting on the clamp assembly as a drill bushing, drill a 3/16" hole through the header. Remove the clamp
assembly from the header and redrill the hole to 13/64". Reinstall the clamp assembly aligning it with the hole just drilled.
Insert the sensor into the fitting so that the tip of the sensor extends ¼" past the center of the header. Tighten the compression nut to
lock it in place.
The EGT sensor cable should always be routed as far away from the ignition system components as possible (plug wires, spark plugs,
ignition coils, distributor or magneto). If the sensor cable is too close to these components it may pick up radiated electrical
interference and cause erratic instrument readings and operation. A distance of at least 6" from these components is desirable in all
installations.
When routing the sensor cable through any panels, be sure to use a rubber grommet to keep the cable from being cut by a sharp edge.
It is also good practice to protect the sensor with a short piece of fuel line at any point that the cable may rub against a hard surface. If
your cable is too long to route back to your instrument fully extended, we recommend sending it back to Digatron to be cut to the
appropriate length for your needs. If you choose to coil your sensor, keep the coil away from the engine.
Route the sensor cable from the motor to the instrument. Secure the cable with cable ties to prevent excessive movement. Attach the
connector to the back of the instrument. The thermocouple cable is brittle and will break at the flex points if not properly tied down. It
is also good practice to protect the cable with a short piece of fuel line at any point where the sensor may rub against a hard surface.
Electrical Interference
If the instrument encounters excessive electrical interference it will display ERR on the left side of the display. The ERR annunciator
can indicate an incorrect instrument or sensor installation. Severe electrical interference can cause the Tach limit and calibration to
reprogram themselves. If your instrument is doing strange things, put it in Set Limits mode and check to see that the limits and
calibration number are still where you set them.
Electrical interference problems can normally be solved by installing a resistance plug boot. We recommend using an NGK boot, #
LB05EMH.
To avoid erratic readings:
• Route the lead as far away from the ignition coil as possible.
• Running your lead through a section of fuel line will protect it from cuts and abrasions, but will not
shield it from ignition
generated interference.
• Be sure that the sensor and the connector fit together snugly.
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