CALIBRATION (PPR/Number of Cylinders):
Until recently, tachometers were calibrated based on the number of
cylinders in the engine. Now, there are all types of engine control
modules (ECMs - on-board computers) and distributor-less ignitions
and the old standard rule—”half the number of cylinders equals the
pulses per revolution (PPR)”—no longer applies. “Pulses per
revolution” relates to how many times the ignition fires per
crankshaft revolution. The tachometer outputs from the ECMs can
range from 1-PPR to 4-PPR for a V-8 engine. So, the new standard is
to refer to PPR instead of the number of cylinders.
SIGNAL INTERFACING:
Stewart Warner Performance tachometers are designed to work with
a wide variety of ignition types, including standard inductive [coil (-)
connection] and any ignition system with a clean tachometer output
signal. The input level can range from TTL 5V (outputs from newer
engine control modules) and 300-400 volt pulses from coil (-) on
most inductive ignition systems. Stewart Warner Performance
tachometers will operate on most traditional capacitive discharge
ignitions when connected to the ignition primary circuit. However,
for high-output CD’s (such as MSD) only connect to the tach output
terminal, never the coil primary. It’s best to consult our tech support
hotline if you’re unsure, rather than risk damage to the tachometer,
ignition or your warranties.
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PROGRAMMING SET-UP (1, 2, 3, 4, 5, 6 PPR):
NOTE: Stewart Warner Performance Tachometers come pre-set
from the plant for a standard 8 cylinder (4 PPR) application.
1. Hold down the Enter/Change button while turning the ignition
switch on.
2. Release Enter/Change Button.
3. The shift-light will light for 1 second to indicate calibration set
mode has been accessed.
4. The needle will go to the previously set range, or the factory
default 4 PPR (indicated by pointer position of 4,000 RPM).
5. Press the Up/Clear or Down/Recall buttons to adjust for the
number of cylinders or pulses per rpm (the pointer will move to
indicate the new setting).
6. To exit programming mode at any time, momentarily press the
Enter/Change button to lock in the setting, or turn ignition
switch off, or if there are no buttons pressed for 5 seconds, the
tachometer will store all changes and exit to normal tachometer
operation.
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SHIFT RPM SET-UP:
1. Turn ignition switch on, engine may be running, or not running,
as you wish!
2. Shift lamp will flash briefly to indicate proper shift-light
function.
3. Press and hold the ENTER button for 1 second until the
shift-light flashes. The flashing of the light in this case
acknowledges entry to the shift setting mode. The tachometer
pointer will now indicate the current shift-light RPM setting.
4. Press the Up/Clear or Down/Recall buttons to adjust the
shift-light RPM set point. The pointer will move up or down to
indicate the new setting.
5. To exit programming mode at any time, momentarily press the
Enter/Change button to lock in the setting, or turn ignition
switch off, or if there are no buttons pressed for 5 seconds, the
tachometer will store all changes and exit to normal tachometer
operation.
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MEMORY RECALL & CLEAR OPERATIONS:
This Tachometer will store 1 current and 1 old peak RPM value. The
stored peak values are shifted through memory, so that the oldest
value is cleared and the current peak is stored as the previous peak
and a new current peak is acquired.
Recalling Current Peak RPM (engine running)
1. With the engine running, press and hold the Down/Recall
button. This will display the current peak RPM and will continue
to update even while the button is held down.
2. Release the button to return to normal operation.
Recalling Peak and Previous Peak RPM (engine not running)
1. Turn the ignition on (the pointer should indicate “0” RPM)
2. Press and hold the Down/Recall button to recall the current
peak RPM.
3. Release, then within 3 seconds, press and hold the
Down/Recall a second time to select the previous Peak RPM.
The shift-light will flash to indicate that you are viewing the
previous peak rpm.
4. Release button to return to return to normal operation.
Clearing Peak RPM
1. Turn the power on (the pointer should be at 0 RPM or
indicating actual RPM if engine is running).
2. Press the Up/Clear button for one second and release. The
oldest stored Peak RPM reading will be cleared, and the current
value will be stored as the previous Peak RPM reading.
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TROUBLESHOOTING:
Q: My tachometer does not respond at all, what do I do?
A: Check all of the wiring connections and power to the
tachometer.
1. If the tachometer needle goes to zero when powered up,
but does not respond when the engine is started, there is
no signal to the green wire. Check to ensure that the
green wire is properly connected to a valid tach signal.
2. If the tachometer needle does not go to zero when
powered up, the tachometer is not grounded properly or
does not have power to the (RED) wire. Check to ensure
a good chassis ground, preferably at the battery ground.
Verify that the (RED) wire has a 12VDC supply.
Q: My tachometer does not read correctly, what do I do?
A: First, determine how the reading is incorrect (example: Double,
half, quarter etc.), then re-set the PPR calibration for correct
readings.
1. If the RPM reads double, re-set the PPR calibration for 1/2
of the current setting.
2. If the RPM reads 1/2, re-set the PPR calibration for 2 times
the current setting.
3. If the RPM reads 1/4, re-set the PPR calibration for 4 times
the current setting.
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CLEANING DIRECTIONS:
qFor proper cleaning of instrumentation/accessories, use a glass
cleaner or mild detergent with a spray on and wipe method.
WARRANTY INFORMATION:
TWO (2) YEAR LIMITED WARRANTY. SWP products are
warranted against defects in workmanship and materials for a period
of two (2) years from the date of purchase. Proof-of-purchase is
required; otherwise, the warranty period shall default to two (2)
years from date-of-manufacture (as indicated by the date code on
the product). See detailed Warranty Policy for other Terms &
Conditions.
STEWART WARNER PERFORMANCE
1-866-SWP-RACE (797-7223)
www.SW-Performance.com
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