CAI Electronic
Programmable Tachometer (EPT)
Introduction
The EPT can be programmed to
accommodate 4, 6 or 8 cylinder
engines and to accept inputs from
Contact Breaker Ignition Systems and
Electronic Ignition Systems.
IMPORTANT INFORMATION
- Only to be fitted to negative
earth vehicles
- Disconnect your
vehicle’s battery prior
to installation
- Operating voltage is nominally 12V (11volts
min 17volts max)
- The Tachometer complies with
CE regulations regarding
electromagnetic compatibility
Input Signals
The EPT can accept input signals
from: -
- The low tension
side of the coil. On contact breaker or
electronic ignition systems (except multispark
and CDI systems)
- Electronic Ignition Systems Dedicated tacho
outputs. (Normally provided when the
electronic system is multispark or CDI)
Programming Your EPT
- Make sure that the battery is
disconnected.
- Make sure that your vehicle
is negative earth.
- Determine number of
cylinders.
- Determine input source, i.e.
either contact breaker or
electronic ignition.
- Remove the black hole plug on
the rear of the tachometer,
by pressing it inwards, just
above it’s centre, and
then inserting a small coin
or screwdriver into the edge
of the plug.
- Removing the plug will reveal
6 switches.
- To programme the number of
cylinders the switches should
be set as follows:-
| No of Cylinders |
Switch1 |
Switch 2 |
Switch 3 |
| 4 |
Off |
Off |
On |
| 6 |
Off |
On |
On |
| 8 |
On |
Off |
On |
This is correct for vehicles with a single
distributor. (The same number of spark lead
outputs from the distributor as the number of
cylinders in the engine) See note (A)
If your ignition system is multicoil and / or
has no distributor
-
For petrol engine applications switch 5 is always ON and switch 6 is always OFF
- Please note, switch 4 adjusts for two types of electronic
ignition, one of which
generates it’s own
voltage output for the tachometer (type
b) and the other which
requires the tachometer supply voltage (type a).
If you do not know the type of ignition you
have, set switch 4 experimentally to OFF. If
this fails and the tacho does not work,
switch to ON and try again.
- To programme the input signal
the switches should be set as
follows:-
| Input Signal |
Switch 4 |
Switch 5 |
Switch 6 |
| Contact Breaker |
Off |
On |
Off |
| Electronic Ignition
(type a) |
On |
On |
Off |
| Electronic Ignition
(type b) |
Off |
On |
Off |
Installation Of Your
EPT
- A hole is needed in
the fascia panel, the
diameter of which will
depend upon the
tachometer purchased,
with sufficient clearance
behind to accept the body
of the tachometer.
- Check that the
battery is disconnected.
- Wire the tachometer
as follows:-
- Green Wire–
Connect to power source
via a 3 amp fuse
- Black Wire–
connect to earth/ground
- Brown/Slate Wire– Not used in this
application
- Red/White Wire–Power
for the tachometer lamp,
connect to a dash
lighting power feed.
- White/Black Wire– For use with Electronic
Ignitions which have a dedicated tacho
output connection, otherwise not
needed. Do not connect to the coil or
distributor.
- Red/Blue Wire– For use when you have
a contact breaker or electronic
ignition without a dedicated tacho
output. Connect to the low tension
side of the coil. Otherwise not
needed.
- The tachometer can
now be installed in the
fascia panel hole, and
clamped against the back
of the panel using the
fixing clamp, spring
washers and knurled nuts
supplied.
- N.B. if the
tachometer is totally
inoperative at this
point, when tested, and
you have an electronic
ignition system, it is
well worth checking the
settings of switches 4
and 5, and determining
whether your system is
type a or b. A simple way
to check is to meter the
voltage output from the
electronic ignition,
tachometer connection, if
voltage is zero, then you
have type a, any kind of
voltage detected would
indicate type b. Make
sure that switches 4 and
5 are set according to
the table in item 8 of
the programming
instructions.
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