Speedhut 3-3_8 inch Tachometer User Manual download pdf

Mount Tachometer in good location for easy viewing. Use included spin ring to secure the gauge.

Hook up the red, black and white wires. (Refer to the schematic above.)

- negative

1 revolution of engine

8 CYL early style single coil example

(fig 1)

Your vehicle ignition system will fall under one of these 4 ignition types. The type of ignition system will determine where the yellow wire is

connected and what the number of pulses per revolution the tachometer should be set to.

Type #1 (single coil) - Up until the 1990’s tachometers picked up the signal from the (-) side on a single ignition coil, reading every pulse sent

to all the cylinders. For example, an 8 cylinder (4 stroke) engine fires 4 spark plugs per revolution or all 8 spark plugs in 2 revolutions.

Connecting the tachometer yellow signal wire to the negative side of the single coil on an 8 cylinder results in pickingup 4 sparks in 1 revolution

(see fig 1). This type of ignition was used pre-dominantly until the 1990’s and distributes sparks to each spark plug. In some vehicles during

the 90’s the coil and distributer merged into one unit, but it is the same ignition system - one coil that distributes sparks to all cylinders. When

connecting the yellow wire to this style of ignition you will be picking up all cylinder sparks (see fig 5).

Type #2 (coil pack) - (fig 2) is a 96 Mustang V8 with twin coil packs. Coil pack #1 (C1) controls the firing of 4 spark plugs and coil pack #2 (C2)

controls the remaining 4 spark plugs. 2 or more separate coils are within each coil pack assembly. In this example each of the 2 coils within each

coil pack sends sparks to 2 cylinders at the same time. When one cylinder is firing in the compression stroke, it’s paired cylinder is “waste” firing in

the exhaust stroke. Each separate coil within the pack is controlled by it’s own trigger wire. In other words, if you hooked up the yellow wire to one

coil trigger wire within one coil pack, it will see only a fraction of the total engine sparks (see fig 5).

1 revolution of engine

8 CYL twin coil packs

(fig 2)

To spark plugs

2 revolutions of engine

8 CYL coil on plug

(fig 3)

Type #3 (coil on plug) – An individual coil is placed directly on top of each spark plug eliminating the spark plug wires. The yellow wire, when

hooked up to any coil, will pick up only 1 pulse per 2 revolutions or 1/2 pulse per 1 revolution (see fig 3). For this type of ignition the yellow wire

from the tachometer will connect to the trigger wire on one of the coils. Typically there will be 3 or 4 colored wires coming off of each coil. The

trigger wire will be the wire that changes color from one coil to the next. For example, all coils may have red, gray and black wires coming off of

them, but the fourth wire will be blue on one coil and green on the next coil.

In summary, figure out how many cylinders you are picking up with the yellow wire and set the respective number of pulses per revolution

(see step 4). The tachometer can be configured to work on .5 pulse (coil on plug) up to 6 pulses per revolution. Use Fig 5 as a starting point

when hooking up the yellow wire.

Caution:

1 Do NOT handle coil wires when car is

running. High voltage is sometimes present.

2. Do NOT try to splice directly into a spark plug

wire. This will damage tachometer.

3. Wear safety glasses.

Ground (black)

+12 volts Dash lighting (white)

(Yellow)

snap connector

negative

coil /tach output

Note: Tie both lighting white wires together

and both black ground wires together.

+12 volts keyed ignition

(Red)

(Black)

Ground

(White)

+12 volts Dash lighting

Power distribution cable to plug all gauges into

Note: Speedhut model G338 series

does not have this plug.

Inverter

INVERTER IS REQUIRED FOR GAUGE DIAL LIGHTING

(Pointer (needle) lighting)

(Main gauge power)

(Gauge Dial lighting)

Inverter/Black Box Note: E18-686-5CR is single gauge inverter to light single gauge. C01-18N-2

& C11-18A01 are multiple gauge lighting inverters that can light up to 8 gauges.

***Protect any unused connectors. Damage to an unused connector could cause inverter failure.***

Power Draw = 0.2 Amp

5 Amp Inline Fuse Recommended

for +12 Keyed Ignition

Most models will have a button on the front of the gauge, but some will come with

an 18” cable with a button on it that will plug into the back of the gauge (left side facing

front of the gauge). This button is for setting PPR (step 4) and displaying peak recall (step 5).

Type #4 (tach output from ECU) Some vehicles will have a tachometer output wire coming from the ECU. The yellow wire from our tachometer

can receive signal from the ECU by following the diagram in fig 4. 4.7k Ω resistor and shrink tubing are included with gauge.

3-3/8" Tachometer Instructions

WARRANTY - Speedhut inc. warrants to the consumer for a period of 5 years from the date of purchase that the product will be free from defects in materials or workmanship.

Speedhut warrants to the consumer for a "LIFE-TIME" that the product circuit board will be free from defects in materials or workmanship.

Please contact Speedhut service department If you have a problem with this gauge.

Speedhut Inc. 165 North 1330 West B2, Orem, Utah 84057 | [email protected] | (801) 221-1460 (9am - 5pm MST)

Setup the Tachometer to run

2 pulses per rev when

connecting it to the engines’ ECU.

ECU

Tachometer (Yellow)

ACC (12v)

4.7K -10K Ω 0.25 watt minimum

(fig 4)

(fig 5: see page 2)

1 2 3

Inverter 1
Gauge Top 2

Summary of Contents

Page 1 - Inverter

Mount Tachometer in good location for easy viewing. Use included spin ring to secure the gauge. Hook up the red, black and white wires. (Refer to the

Page 2 - Gauge Top

Set the # of pulses per revolution.5 pulseper rev1 PPR2 PPR3 PPR4 PPR5 PPR6 PPR4x 1000Programming ButtonSome models required the use of an auxiliary b

Page 3

Set your shift light LED brightness7A unique day and night shift light LED brightness setting can be set on the tachometer. This setting eects intern

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Speedhut 3-3_8 inch Tachometer User Manual

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