1992 HONDA PRELUDE valve

Engine Oil

Checking Engine Oil

Check the engine oil a couple of
minutes after shutting off the
engine. This will allow the oil to
drain down to the bottom of the
engine. Make sure the car is parked
on level ground.
1. Pull out the dipstick (orange
loop) and wipe it with a cloth orpaper towel.

2. Insert
it all the way back in its

tube.

3. Pull
it out again and look at the
oil level at the end of the dipstick.
If it is between the upper and
lower marks, the level is correct.
Add oil if the level is at or below
the lower mark.
Adding

To add oil, unscrew and remove the
oil filler cap on top of the valve
cover. Pour in the oil, and replace
the filler cap. Tighten it securely.
Wait a few minutes and recheck
the oil level. Do not fill above the
upper mark; you could damage the

engine.

Maintenance

UPPER MARK
LOWER MARK
OIL FILLER CAP
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Anti-lock Brake System

The Anti-lock Brake System (ABS) is standard equipment on the
Prelude Si, Si 4WS sold in the U.S.
and SR, SR 4WS sold in Canada. It
is not available on any other models.
The ABS works by measuring how
fast the wheels are turning during
braking and comparing their speed.If any wheel is rotating much
slower than the others (on the
verge of locking up and skidding),
the system reduces hydraulicpressure to that wheel's brake
caliper. When that wheel's speed
matches the other wheels, the
system applies normal hydraulic pressure. This can take place
several times per second at each
wheel. You feel the ABS working as rapid pulsations in the brake

pedal.
Each wheel has a wheel speed
sensor assembly. As the wheel
rotates, the sensor sends electrical
pulses to the ABS control unit. The
pulse frequency varies with the
wheel speed.
The electrical output of the ABScontrol unit is connected to the
modulator/solenoid unit. During
braking, the ABS control unit monitors the pulse frequencies
from the four wheels. When the control unit detects a wheel locking
up, it energizes the appropriate
solenoid in the modulator/solenoid
unit. There are three solenoids: one
for each front wheel, and one for
the rear wheels. The energized solenoid reduces hydraulic pres-
sure to one side of a modulator
valve. This, in turn, reduces hydrau- lic pressure in the brake line going
to the affected wheel. When that
wheel speeds up because of the re- duced braking effort, the control unit de-energizes the solenoid. This
builds hydraulic pressure on the
modulator valve. The pressure in-
creases in the hydraulic line to the

wheel.

For the system to react quickly, the
modulator/solenoid unit must have
brake fluid under high pressure.
This is supplied by an accumulator
that is pressurized by an electric pump. A pressure-sensing switch
on the accumulator controls this
pump.
The control unit also contains error detection circuitry. It monitors the
operation of the wheel sensors, solenoids, pump, and electronics. If
the control unit detects any faults,
it shuts off power to the pump
motor and solenoids. The light on
the instrument panel comes on.
The brakes then work like a conventional system without anti-
lock capabilities.

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Emission Controls

The burning of gasoline in your
car's engine produces several by-
products. Some of these are carbon
monoxide (CO), oxides of nitrogen
(NOx) and hydrocarbons (HC).
Gasoline evaporating from the tank
also produces hydrocarbons. Con-
trolling the production of NOx, CO,
and HC is important to the environ-
ment. Under certain conditions of
sunlight and climate, NOx and HC
react to form photochemical "smog."
Carbon monoxide does not contri-
bute to smog creation, but it is a
poisonous gas.
The Clean Air Act

The United States Clean Air Act*
sets standards for automobile
emissions. It also requires that
automobile manufacturers explain
to owners how their emission
controls work and what to do to
maintain them. This section
summarizes how the emission con-
trols work. Scheduled maintenance

is on page 129 .

* In Canada, Honda vehicles

comply with the Canadian Motor
Vehicle Safety Standards (CMVSS)
for Emissions valid at the time they

are manufactured.
Crankcase Emission Control

System

Your car has a Positive Crankcase
Ventilation (PCV) System. This
keeps gasses that build up in the engine's Crankcase from going into
the atmosphere. The PCV valve
routes them from the crankcase
back to the intake manifold. They
are then drawn into the engine and

burned.

Evaporative Emission
Control SystemAs gasoline evaporates in the fuel
tank, a canister filled with charcoal
adsorbs the vapor. It is stored in
this canister while the engine is off.
After the engine is started and
warmed up, the vapor is drawn into the engine and burned during

driving.

Technical Informatio n
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