Gauges & Instruments found in OEM Applications, and Optional &
A tachometer is an instrument that measures
the rotational speed of the motor's crankshaft. The tachometer displays
the revolutions per minute (RPM) on a calibrated analog dial or digital
display. The tachometer is one of the most important gauges
providing important information such as, engine RPM, optimal shifting
points, and maximum engine RPM known as the Red Line, not to be exceeded
as serious engine damage could occur.
Oil Pressure gauge or indicator light is the most important gauge of an
engine. Oil is the blood of an engine. Oil pressure is
essential to keeping an engine's moving parts lubricated. If oil pressure is too low, the
engine can seize up or sustain serious internal damage.
Oil pressure that is too high (higher than normal) could indicate a plugged oil
filter or an oil pressure valve stuck in the closed position.
Surprisingly the oil pressure gauge appears on most vehicles as a "dummy
light" that displays when oil pressure is too low. If the oil
pressure light or indicator comes on or the gauge enters the high or low
danger zones while the engine is running, it is important to safely pull
over and stop the engine before serious internal damage occurs. This may
indicate the oil pressure is low (or too high) and the lubrication system
is not working properly.
cooling system of an engine is designed as a sealed system with the engine
coolant held under pressure. When under pressure, water and engine
coolant boil at a higher temperature. As your coolant and water
increase in temperature and approach the boiling point, the state of the
liquid begins to change to a gas, seen as steam.
The water temperature gauge indicates the engine's operating temperature
allowing the driver to monitor the cooling system to protect the engine from overheating
and ensure maximum
Fuel level meter
or fuel gauge is used to monitor the
amount of fuel in the tank to prevent the driver from running the fuel
tank dry. In many cases running the tank dry can cause problems. Fuel gauge indictors are usually mounted within the tank
and do not account for fuel in the filler tube that is above the fuel tank
("topping off" the tank).
The voltmeter measures
the current voltage across the
battery terminals when the engine is not running, and reads the voltage
provided by the charging system voltage
when the engine is running. Having a gauge that measures the current
voltage is important for
modified vehicles vehicles and automotive audio enthusiasts because if the
voltage used exceeds the voltage supplied by the charging system, the
battery is drained.
In addition, excessive voltage supplied by the charging system can damage
the battery and other electrical components, including the vehicle's ECM
computer (Electronic Control Module). Many vehicles have a light
indicator that tells the driver the voltage is outside of the recommended
range of operation.
odometer (also known as a mileometer or milometer) is a gauge used for
indicating distance traveled by the vehicle. On older vehicles,
odometers may possibly only indicate up to a value of 99,999 where this
number was adequate based on expected live of the engine. At 100,000, the
odometer would restart from zero. This is known as odometer rollover.
Modern vehicles now commonly travel into the hundred thousands of
miles/kilometers. Newer vehicles produced since 1980 have odometers
that can measure up to a value of 999,999. A common form of fraud is
to tamper with an odometer, rolling back the currently displayed number;
often referred to as clocking. This is done to make a car appear to have
been driven fewer miles/kilometers than reality, thus increase its
apparent market value. Today many newer cars use digital odometers making
it difficult (but not impossible) to manipulate the mileage
Check Engine warning light / malfunction indicator lamp tells the driver
that there is a problem or
potential problem somewhere in the emission control system.
speedometer is a device that measures the current speed of a land
vehicle. Most speedometers are The "eddy-current" speedometer, which
has been used for over a
century and is still in widespread use today. Up until the 1980s and the
introduction of electronic speedometers, the eddy-current
speedometer was the only type commonly used. The
eddy-current speedometer uses a rotating flexible cable usually driven by
gearing linked to the tail shaft (output) of the vehicle's transmission or
Many modern speedometers are electronic. With modern electronic
speedometers, a rotation sensor, usually
mounted on the rear of the transmission, delivers a series of electronic
pulses whose frequency corresponds to the rotational speed of the
driveshaft. The sensor is typically a toothed metal disk located between a coil and a magnetic field sensor. As the disk turns, the teeth
pass between the two, each time producing a pulse in the sensor as they
affect the strength of the magnetic field it is measuring. A
computer converts the pulses to a speed and displays this speed on an
electronically-controlled, analog-style needle or a digital display. Pulse counts may also be used to
increment the odometer. Speedometers are not totally accurate, and
most speedometers have tolerances of some 10% plus or minus due to wear on
tires as it occurs. Modern speedometers are said to be accurate within 5%
but as this is legislated accuracy, this may not be entirely correct.
When vehicles are modified with taller tires or altered gearing somewhere
in the drive train the final speedometer reading may be considerably off
from factory. A different speedometer gears can be substituted to
bring the speedometer back into a reasonably accurate range.
An ammeter is a measuring
gauge or instrument used
to measure the electric current in a circuit. Electric currents are
measured in amperes, hence the name ammeter, which is commonly
misspelled or mispronounced as "ampmeter" or "ameter".
The ammeter measures the electrical current (the amperage) charging or discharging
the battery. The ammeter monitors the output coming from the alternator back to
the battery and is used to indicate any problems in the system. Excessive charging
current can damage the battery and other electrical components while
inadequate amperage coming from the the alternator will not charge
the battery leading to battery failure. This meter
would be recommended for vehicles where many accessories have been added
such as offroad lights, a winch, amplifiers and audio / visual equipment,
all of which will increase strain on the
battery and alternator.
The fuel pressure meter displays the
pressure that is built up in the fuel lines between the fuel pump and the
carburetor (typically 0-15 psi) or between the fuel pump and the fuel
injectors in fuel injected engines (typically 0-100 psi) . Insufficient fuel pressure in both carbureted
and fuel injected systems would starve the engine of fuel, causing a
no-start or stall condition. If the engine is starved of fuel while running, it
will run lean, which can cause excessive combustion temperatures and lead
to engine damage or destruction. Excessive fuel pressure in a carbureted
fuel system could flood the carburetor with fuel; and in a fuel injected
system, it could damage the fuel injectors, causing them to leak.
A boost meter is used on
vehicles with a turbo
system. It is used to allow the driver to monitor the increase
in intake pressure, known as boost, which is provided by the turbocharger. Excessive boost pressure can cause
detonation, which will damage or destroy an engine.
A vacuum meter is used to monitor the
amount of negative pressure or suction in the intake manifold. Reading a
vacuum meter is a common diagnostics procedure to diagnose a variety of engine problems, from a
blown head gasket to worn valve guides as well as monitoring
fuel economy. When monitoring
fuel economy a high vacuum readings indicating good fuel economy and
low vacuum readings indicating poor fuel economy.
temperature is essential to the life and performance of any modified
engine. If the engine oil is too hot, viscosity breakdown and oil
oxidation will occur and the engine oil will not be able to protect the
Similar to oil temperature, transmission
fluid temperature is important to the life and performance of the transmission. If the
transmission fluid is too hot, the transmission fluid will oxidize causing gum and varnish to form, which will cause the transmission
valves to stick. The oxidation can also cause the transmission bands and
clutches to slip, which could lead to major transmission damage.
When you step down on the
brake pedal and force is applied to the brake system's
master cylinder piston, pressure in the hydraulic system increases,
forcing fluid through the lines to the slave cylinders located at the
wheels. The Brake
Pressure Gauge is used to monitor pressure in the hydraulic brake system.