1991 HONDA CIVIC engine controls

Introduction

This manual contains important information about the safe operation and maintenance of your car.
We urge you to read it carefully, become familiar with the controls itdescribes, and follow its recommendations, to help make your
driving trouble-free and enjoyable.
Statements or labels on the product preceded by the following
words are of special significance:
indicates severe personal injury or death will result if
instructions are not followed.indicates a strong possibility of severe personal
injury or death if instructions are not followed.means hazards or unsafe practices which could
cause minor personal injury or product or property
damage.
NOTE: gives helpful information.
Break-in Period
During the first 600 miles (1,000 km) of driving, avoid full throttle
starts and cruising for extended periods at a constant speed.

NOTE:
This break-in procedure also applies to exchanged or overhauled

engines.
During and after the break-in period, drive the car at moderate
speeds until the engine is fully warmed up.
During the first 200 miles (300 km), try to avoid severe braking.

Brake misuse during this period will reduce future braking efficiency.

Remember, your Honda Automobile dealer knows your car best,and should be consulted for service assistance and advice.ProCarManuals.comMain Menu s t

For proper operation of your car's emission controls, your engine is

designed to use unleaded fuel only.

CAUTION:
Using leaded or even low-lead gasoline could damage some of your
emission controls, and also void their coverage under the emission
controls warranty.
Use gasoline from pumps labeled unleaded, with a pump octane
number of 86 or higher. The pump octane number is an average of
the Research (R) octane and Motor (M) octane numbers. Use of a lower octane gasoline can cause persistent, heavy "spark knock" (ametallic rapping noise), which can lead to engine damage if severe.
CAUTION:
If you notice steady spark knock while holding a steady speed on a
level road, try changing brands of gasoline. If the spark knock persists, consult your Honda dealer. Failure to do so is considered
misuse, and misuse is not covered under the New Car Warranty.
Occasionally you may notice light spark knock while accelerating or
driving up hills. This is no cause for concern, it simply means your
engine is running at its most economical.
Gasoline Containing AlcoholIf you decide to use a gasoline containing alcohol ("gasohol"), be
sure its octane rating is at least as high as that recommended for
unleaded gasoline. There are two types of "gasohol": that
containing ethanol, and that containing methanol. Do not use
gasohol that contains more than 10% ethanol. Do not use gasoline
containing methanol (methyl or wood alcohol) that does not also contain cosolvents and corrosion inhibitors for methanol. Never use
gasoline containing more than 5% methanol, even if it has cosolvents and corrosion inhibitors.

NOTE.
Fuel system damage or vehicle performance problems resulting
from the use of such fuels is not covered under the new car warranties. Honda cannot endorse the use of fuels containing methanol since evidence of their suitability is as yet incomplete. Before purchasing fuel from an unfamiliar station, try to confirm
whether the fuel contains alcohol, of what kind, and how much. If
you notice any undesirable operating symptoms after using a
gasoline that contains alcohol; or one that you think contains alcohol, switch to an unleaded gasoline, as recommended above.
GasolineProCarManuals.comMain Menu s t

Evaporative Emission Control System
The Evaporative Emission Control System is designed to prevent
fuel vapors from escaping into the atmosphere. Fuel vapors from the fuel tank are directed into the charcoal
canister where they are adsorbed and stored while the engine is stopped or idling. When the coolant temperature rises to a certain
value, the vapors are drawn into the engine through the throttlebody and the intake manifold during normal engine operation.
Engine Exhaust Emission Controls
The engine exhaust emission control systems are designed to control combustion during idle, acceleration, cruise, and deceleration.
These systems are entirely separate from the crankcase and evaporative emission control systems described previously.
HONDA PGM-FI System
The PGM-FI system consists of three independent sub-systems; Air Intake, Electronic Control and Fuel Control, thus allowing moreaccurate control of air/fuel ratios under all operating conditions.
The Electronic Control Unit (ECU) detects the amount of air
drawn into the cylinders and determines the amount of fuel to be injected to provide the optimum air/fuel ratio for all engine needs.
Ignition Timing Control System
This system automatically controls the ignition timing to reduce
the amount of HC and NOx.
Catalytic Converter
Three Way Catalyst
The catalyst is used to convert hydrocarbons (HC), carbon monoxide (CO) and oxides of nitrogen (NOx) in the exhaust gas,

to carbon dioxide (CO 2
), dinitrogen (N 2
) and water vapor.

Exhaust Gas Recirculation (EGR) (California automatic models except EX Sedan)
The EGR system is designed to control the formation of oxides of nitrogen (NOx) caused when fuel mixture burns at high
temperature. It works by recirculating exhaust gas through the EGR valve and intake manifold into the combustion chambers
where it reduces peak temperature by diluting the air/fuel mixture.ProCarManuals.comMain Menu s t

Index

Battery
Charging System Warning Light.............................................. 30
Jump Starting ........................ 110
Maintenance............................. 89
Specification (Hatchback).... 116
Specification (Sedan)............ 119
Beeper System Fasten Seat Belt Beeper(Sedan).................................. 11

(Hatcback)............................ 15

Belts, Seat............. See "Seat Belts"
Body Repair.................................. 102
Brake Warning Light...................... 31 Brakes
Brake Failure Warning Light.... 31

Brake Fluid................................ 84

Brake System Design.............. 83
Brake Wear Indicators............. 84
Parking Brake........................... 42
Parking Brake Warning Light.. 31
Break-in Period................................. 2

Bulb
Replacement............................
92

Specification (Hatchback)....
117
Specification (Sedan)............

120
Buzzer........... See
"Beeper System"
Capacities (Hatchback)............... 115 Capacities (Sedan)....................... 118
Care and Cleaning.......................... 99
Catalytic Converter..................... 126 Certification Label....................... 121
Chains, Tires...................................

95
Check Engine
Warning Light......... 31
Child Proof Door Locks...................

5

Child Restraint
System................. 21
Cigarette Lighter............................ 44

Clock............................................... 42
Clutch Pedal Adjustment.............. 61
Compact Spare Tire.................... 104
Coolant Temperature Gauge ........

28
Cooling (with
A/C).........................

49

Cooling System..............................

80

Crankcase Emission Control
System................................... 124
Cruise Control Operation.................................. 39
Indicator.................................... 31

Defogger........................................ 34
Defroster........................................ 51

Doors
Child Proof Door Locks............. 5

Locks........................................... 3

Power Locks.............................. 4

Emergency
Changing a Flat Tire............... 105
Hazard Warning System ......... 37If Your Car Gets Stuck.......... 112
Jump Starting........................ 110

Shoulder Belt Buckle............. 113

Towing.................................... 111
Warning and Indicator Lights.. 29
Emission Controls........................ 124

Engine
Coolant...................................... 80

Coolant Temperature Gauge... 28
Exhaust Controls................... 125Identification Number............ 12

1
Oil and
Filter.............................. 76
OH Pressure Warning Light..... 30
Specification (Hatchback).... 116
Air Conditioner
Operation.................................. 47

Service...................................... 98

Air Filter.......................................... 86

Air Pressure, Tires......................... 94
Antifreeze.. See "Radiator Coolant" Anti-theft Steering Column Lock System ..................................... 57
Appearance Care........................ 100

Ashtrays......................................... 44

Automatic Seat Belt...................... 10

Automatic Transmission
Driving Technique.................... 66

Fluid........................................... 79

Operation.................................. 64

(cont'd)ProCarManuals.comMain Menu s t