1990 Honda Accord - Overview

With the introduction of the new 1990 model, the Honda Accord enters its fourth generation with automobiles designed to provide a higher level of sophistication, comfort and style. The new Accord 2-door coupe and 4-door sedan are longer, wider, roomier, more powerful and have a contemporary, international look. Engineered for smooth and silent running, they combine performance with comfort and are built to Hondas high quality standard.

The new Accord's styling is sleek and distinctive. It blends traditional Accord design elements-wedge profile, large greenhouse, aggressive hoodline-into an entirely new shape defined by softer contours and smoothly flowing lines. With a substantially increased glass area, flush surfaces and a wide stance, the new Accord combines sporty looks with practical improvements like a more rigid chassis, improved visibility and increased occupant space.

The structural integrity of the new Accord's body has been increased by a complete redesign. With more torsional and bending rigidity, the chassis provides a stable platform for the Accord's improved 4-wheel independent double wishbone suspension system. A new speed-sensitive, variable-assist power steering system maintains road feel while keeping steering effort at a comfortable level.

Under the hood, there is a new 2.2 liter 4-cylinder, SOHC 16-valve engine, with a Honda-designed secondary balancer system, which significantly reduces vibrations. It's tuned for smooth power delivery in the low to mid ranges, where most driving occurs, and complemented by a pair of new transmissions: a 5-speed manual or a compact, electronically controlled, 4-speed automatic with driver-selectable Sport mode and lockup torque converter.

The new Accord's increased size provides more interior space, and the seats, fittings and trim have been redesigned to take full advantage of it. Front seat occupants enjoy larger seats, and rear occupants have more leg and foot room. Interior fabrics and trim are carefully selectedto enhance the bright, airy feeling in the Accord's large cabin, and help create a feeling of comfort and well being.

The new Honda Accord strikes a fine balance between style, comfort, ride, performance and handling. lt is a highly refined automobile that is engineered and built with uncompromising attention to quality, and is a worthy successor to a highly respected line of cars.

MODELS AND TRIM
The 1990 Accord is available in two body configurations, 4-door sedan and 2-door coupe. Both are identical in exterior dimensions except for height: the coupe is 20 mm (0.79 in.) lower. There are three Accord trim levels: DX, LX and EX.

The DX includes such standard features as tinted glass, adjustable steering column, speed-sensitive, variable-assist power steering, reclining front seatbacks, remote trunk and fuel filler door releases, tachometer, and in 4-door sedans, child-proof rear door locks.

Accord LX versions have, in addition, standard power windows, dual power side mirrors, AIN4IFM stereo cassette sound system, cruise control, and air conditioning.

The Accord EX offers a higher output engine, sport-tuned suspension, driver's seat adjustable lumbar support, power moonroof, alloy wheels, and an AM/FM ETR High-Power stereo cassette sound system.

Most of the Accord's comfort and convenience features are standard. Only a few options are available, including an electronically controlled 4-speed automatic transmission with lockup torque converter.

THE ACCORD STORY
The introduction of the first Accord in June of 1976 was significant for both the American Honda Motor Co., Inc. and the automobile industry as a whole. For Honda, then known mainly for its economical Civic, it was the first step toward becoming a full-line auto manufacturer and a major presence in the U.S. car market. For the industry, the Accord defined a new kind of car-a practical automobile that combined economy and value with sporty style and spirited performance.

That first generation Accord was available only as a 3-door hatchback. It was 162.8 inches long, had a 93.7-inch wheelbase and was powered by a 1.6 liter, CVCC 4-cylinder engine. Only one trim level was available and the suggested price was $3,995. In all, 18,333 Accords were sold that first year.

The original Accord design was refined over the years and new models were added. An upscale LX version appeared in 1978, and in 1979 a 4-door sedan was introduced along with a more powerful, 1.8 liter engine. The first generation Accord enjoyed a long and successful run through the 1981 model year.

The next all new Accord debuted in the fall of 1981 as a 1982 model. This generation included the first passenger cars built in America by a Japanese automobile company. Honda of America Manufacturing began production of Accord 4-Door Sedans in Marysville, Ohio, in November of 1982.

The third generation was launched in 1986 with five versions: the DX Hatchback, DX 4-Door Sedan, LX 4-Door, LXi Hatchback, and LXi 4-Door. Longer and more luxurious, these Accords had a 1955 cc engine and 4-wheel independent double wishbone suspension. In 1988, a new coupe was added to the line, which had grown to include seven versions offering a wide variety of trim and equipment choices.

Over the years the Accord has progressed steadily upward in class, to the point where it is often compared to more expensive European sedans. With the fourth generation, the Accord moves further up the scale as it continues to set new standards for the competition.

Honda Accord Chronology

1976
Launched in June as a 1976 model, the first Accord has a 93.7-inch wheelbase, 162.8-inch overall length and is powered by a 1600 cc, 4-cylinder OHC "CVCC" engine. Suggested retail price is $3,995.

1977
Essentially a carryover model, the '77 Accord is EPA-rated at 38 mpg/city and 48 mpg/highway. Base price: $4,595.

1978
The Accord LX Hatchback is added to the line with variable-assist power steering as standard equipment. Base price: $5,229; $6,095 for the LX.

1979
A new 4-Door Sedan expands the Accord line to three models:

Hatchback, LX Hatchback, and 4-Door Sedan. Engine displacement is increased from 1600 cc to 1751 cc. Base prices: Hatchback $5,949; 4-Door Sedan $6,515; and LX Hatchback $6,949.

1980
A 3-speed automatic transmission replaces the 2-speed previously available. Base prices: Hatchback $6,199; 4-Door Sedan $6,765; and LX Hatchback $7,199.

1981
New SE (Special Edition) 4-Door brings the Accord line to four versions in the last model year of the first generation. Base prices: Hatchback $7,249; 4-Door Sedan $7,895; LX Hatchback $8,229; and SE Sedan $9,950.

1982
Second generation is introduced as 1982 models in the fall of 1981. With all-new bodies, these Accords have a 96.5-inch wheelbase. Base prices: 3-Door Hatchback $7,399; 4-Door Sedan $8,245; and LX Hatchback $8,499.

1983
Production of 1983 Accord 4-Door Sedans begins in November 1982 at the Honda of America Manufacturing plant in Marysville, Ohio. Special Edition 4-Door Sedan is added, with moonroof and leather trim, and the automatic transmission has four speeds rather than three. Base prices: Hatchback $7,499; 4-Door Sedan $8,345; LX Hatchback $8,549; and SE 4-Door $11,795.

1984
Engine size is increased from 1751 cc to 1829 cc, raising horsepower from 75 to 86. Base prices: Hatchback $7,699; LX Hatchback $9,949; 4-Door Sedan $8,549; and LX Sedan $9,949.

1985
New SEi Sedan with fuel-injected engine added to line, along with 4-speed automatic transmission with lockup torque converter. Last model year for second generation Accord. Base prices: 3-Door Hatchback $7,895; LX Hatchback $9,095; 4-Door Sedan $8,845; LX Sedan $10,295; and SEi 4-Door Sedan $12,945.

1986
The third generation Accord, introduced in the fall of 1985, featured a longer, 102.4-inch wheelbase, new body styling, larger 1955 cc engine, and retractable halogen headlights. New 4-wheel double wishbone independent suspension is an important technical advance. Base prices: DX Hatchback $8,429; DX 4-Door Sedan $9,229; LX 4-Door Sedan $10,995; LXi Hatchback $11,149; and LXi 4-Door Sedan $12,675.

1987
Essentially the same lineup as 1986, with some detail changes. Base prices: DX Hatchback $9,759; DX 4-Door Sedan $10,625; LX 4- Door Sedan $12,799; LXi Hatchback $12,785; and LXi 4-Door Sedan
$14,429.

1988
A new coupe, exclusively produced at the Marysville plant, is a major addition to the Accord line. Base prices: DX Hatchback $10,535; DX 4-Door Sedan $11,175; DX Coupe $11,335; LX 4-Door Sedan
$13,460; LXi Hatchback $13,695; LXi 4-Door Sedan $15,200; and LXi Coupe $14,460.

1989
SEi versions of Sedan and Coupe feature 4-wheel disc brakes, leather-trimmed interior, and Honda/Bose Music System in final year for third generation Accord. Current base prices: DX Hatchback $11,230; DX 4-Door Sedan $11,770; DX Coupe $11,650; LX 4-Door Sedan $14,180; LXi Hatchback $14,530; LXi 4-Door Sedan $15,920; LXi Coupe $14,690; SEi 4-Door Sedan $17,985; and SEi Coupe $16,975.

®Bose is a registered trademark of Bose Corporation, covered by patent rights issued and/or pending.

Honda Accord Sales in the U.S.

1990 Honda Accord - Body

OVERVIEW/DESIGN OBJECTIVES
The 1990 Accord has a fresh, new style that gives it a distinct, international look while reflecting traditional Accord design themes. Beneath the skin, its architecture is all new, redesigned for greater structural integrity. Its cabin is spacious, bright, and the focus of its overall design.

The Accord's unit body is stronger and more rigid, with extensive designed-in corrosion protection. Heavier gauge steel is used in many exterior panels, not only to increase strength but to ensure a feeling of quality and substance. Designers concentrated on reducing the number of seams, refining fit and finish and countless other details in an effort to create the perception, as well as the reality, of solid quality.

Larger in every major exterior dimension, the new Accord also has more interior space, particularly for rear seat passengers. And the interior, because of the Accord's large glass area, has an airy, open feeling.

Honda Accord Exterior Dimensions

STYLING
The styling of the new Accord gives it a strong visual presence. Its look is refined and contemporary, with an international, European sedan flavor. Though a completely new design, it retains traditional Accord styling cues, like a sharply sloping hood, large glass area, wedge shape and high rear deck.

A central element of the design is the Accord's long cabin area, or greenhouse. Taking advantage of the car's added length, Honda designers moved the leading edge of windshield forward 150 mm (nearly six inches) and raked the glass back at a sharper angle. This shortened the hood, giving it a more aggressive look while softening the transition between the hood and windshield lines. Additional cabin length was added in the rear as well, allowing for a sharply swept rear glass without compromising rear seat headroom.

The front of the new Accord is rounded and set off by clear-lens, flush headlights that accentuate its width and add sparkling counterpoints to the flush bumper and front skirt. These halogen headlights are a new Honda design. Unlike conventional lamps, which focus the light through the lens, these have a clear lens and the light is directed by the faceted reflector.

The surface of the new Accord is nearly flush; there's just a 3 mm (0.12 in.) difference between glass and metal planes. Extensive wind tunnel testing was done to reduce wind noise, particularly along the A-pillars and top front corners of the car.

The Accord's profile is defined by a subtle character line which curves smoothly along the upper body, uniting the rounded front with the squared-off rear portion of the car. The side window frames accentuate the glass-to-metal relationship. (Glass area has been increased substantially: the windshield by 20 percent, the side windows by 17 percent and the rear window by 14 percent.) These elements combine with the Accord's short front and rear overhangs, wide stance, larger wheels and tires, and long wheelbase to give it a distinct personality and strong visual authority.

STRUCTURE
The rigidity of the Accord's unit-body has been increased, in every axis, through a combination of design refinement and the use of heavier gauge panels in high-load areas and the suspension mounting structure. The greater stiffness of the platform results in improved ride and responsive handling, reduced noise and vibration, and gives the car a solid, high-quality feel.

The body's torsional rigidity is increased by 20 percent and its bending rigidity by 30 percent. Equal or greater improvements in structural integrity were realized by redesigning the doors, floor pan, side sills, pillar cross sections, and the hood and deck lids. The doors, in particular, were strengthened to accommodate the larger windows, and the thickness of their outer skin was increased. New latch mechanisms were designed so that the doors close easily with a solid, high-quality sound.

WINDSHIELD WIPERS
Since the glass area of the new Accord's windshield is considerably larger than before, a new, completely integrated, modular windshield wiper system was designed. It incorporates a more powerful motor, linkage and other components into a single, modular unit contained in a lightweight aluminum frame. Air flow data was used to locate the windshield washer nozzles to minimize disturbance caused by vehicle speed.

MOONROOF
Anew, more compact framework was designed for the moonroof, a standard feature of the Accord EX Sedan and Coupe. Its components are arranged in a single plane rather than in layers, making it 13 mm (0.51 in.) thinner, thus providing that much more headroom.

CORROSION PROTECTION
Corrosion resistant materials and special treatments are used in 85 percent of the Accord's body, with primer and paint covering the rest of its surface area. These include galvanized steel, zinc phosphate coating, urethane foam, and the injection of anti-rust wax. In areas particularly prone to corrosion, plastic and resin components are used; the fuel filler door, for example, is a thick, one-piece plastic moulding. Resin panels and splash shields line the entire lower perimeter of the car, from the bumpers to the side sills and inside the wheelwells, for further corrosion protection.

A major design priority was the elimination of flanges. These are exterior seams, often seen in the underbody and beneath the side sills, that are difficult to treat for corrosion resistance and are susceptible to rust. Instead, most of the Accord' s exterior body and chassis panels are joined by overlapping them so that flange joints are not necessary.

1990 Honda Accord - Interior

OVERVIEW/DESIGN OBJECTIVES
The overall increase in the 1990 Accord's size is best appreciated from within the car. There is more all-around room and the lengthened cabin and large glass area gave Honda designers great flexibility in creating a bright, airy interior environment. Their design criteria called for soft surfaces, the elimination of seams and cut lines, and the logical placement of instruments and controls.

The new Accord's lengthened wheelbase allows the front seat positions to be moved 40 mm (1.6 in.) further forward, providing more space for rear seat passengers and increasing the distance between occupants. Advancing the windshield's leading edge 150 mm (5.9 in.) and increasing its angle had the effect of lowering the cowl line for improved forward visibility and providing space for a low, deep instrument panel-manufactured in one piece using an innovative new process-which accentuates the feeling of space for front seat passengers.

ONE-PIECE, INTEGRATED INSTRUMENT PANEL
Conventional instrument panels consist of many panels held together with screws, bolts and clips. The instrument panel of the new Accord is an industry-leading, one-piece design that eliminates most of these fasteners and integrates many under-dash components into a single unit. It is lighter, more noise absorbing, less prone to squeaks and rattles, and, with its smooth exterior, more pleasing to the eye- the only seams are around the glove compartment and the instrument and control panel.

A new three-step vacuum forming process was developed to manufacture this panel. First, the soft-surface outer covering is laid up in a steel mold. Next, a backing layer of urethane is injected into the mold. Then, the various components-such as mounting flanges for subsystems, ventilation ducts and reinforcement panels-are bonded to the unit with a final layer of urethane.

INSTRUMENTATION AND CONTROLS
The new Accord's high-position instruments and controls are in clear sight and easy reach. The analog gauges, with crisp white numerals on a black background, are located in a pod directly in front of the driver; there's a large speedometer in the center, flanked by a tachometer and fuel and temperature gauges.

This instrument module, which also contains warning lights, shift-position and vehicle status displays, is a self-contained, electronic unit. Though the display is analog, the information is received from sensors in the transmission through wires and multi-pin connectors. There are no cables; the speedometer, tach and odometers are electronically actuated.

The headlights, wipers and turn signals are controlled by stalks on the steering column, and the switches for the side mirrors and power windows are set into forward portions on the door armrests. In cruise control-equipped models, the "Resume" and "Set" switches are located on the steering wheel.

SEATING AND TRIM
The Accord's front seats are a new design. They are larger-with 35 mm (1.4 in.) longer seats and 25 mm (1.0 in.) higher backs-and are supported by a U-shaped steel frame, rather than a conventional perimeter frame. The open portion of the U faces the rear and increases under-seat foot room by 30 mm (1.2 in.). In addition, the seat tracks have been modified to provide more lateral foot space. Both front seats have reclining backs, bolsters for lateral support, and EX models have a driver's adjustable lumbar support. The lap belt anchor on the driver's side slides with the seat when it's adjusted, making the belt more comfortable and easier to use.

The rear seat is contoured for better comfort and support. Its seat cushion is a one-piece molding of foam over a spring-steel frame and both outboard positions have three-point belts. There's a fold-down armrest between the seats.

The seamless, soft-touch motif is carried through in the moulded door panels and one-piece headliner, whcih has recesses for the interior lamp, passenger-assist handles and windshield visors so they all fit flush. The headliner is bonded to a honey comb backing which absorbs nouise and vibration and reinforces the roof panel. Similarly, the floor is damped with sandwiched materials for both rigidity and acoustic absorption.

VENTILATION
The cooling, heating and air flow capacity of the Accord's ventilation system has been increased significantly by a new, compact system that's also quieter and more efficient. The system's heating capacity is increased, cooling capability is improved, and air flow is up from 420 cubic meters per hour to 500. The low air-resistance design of the air ducts and vents has reduced the noise level from 69 decibels to 67.

Located entirely under the instrument panel, the system integrates a twin-fan, high-capacity blower, a low-friction heat exchanger and a high efficiency heater core with an efficient network of high-flow ducts. Adjustable vents are located at both ends of the instrument panel, in the center, and at floor level.

Ventilation system controls are large and easy to use, with dials for fan and temperature settings, and soft-touch butons, with laser-cut symbols, for vent and defroster selection.

1990 Honda Accord - Chassis

OVERVIEW/DESIGNER OBJECTIVES
The 1990 Accord's newly designed chassis and suspension system provide a harmonious balance of a smooth and stable ride, responsive handling, positive steering feel and sure braking.

The key to achieving this balance is the Accord's rigid body structure and strengthened fron subframe, which help keep flex to a minimum so that proper suspension alignment is maintained. Because of its increased length, the new Accord also has a more favorable 61.5/ 38.5 front-to rear weight distribution, further contributing to better handling and braking.

The Accord uses a redesigned 4-wheel independent double wishbone suspension system, and for improved road feel, a new speed-sensitive, power-assisted steering system. Also, wheel size is increased with larger diameter front disc and rar drum brakes, actuated by a new tandem power brake booster.

SUSPENSION
Though the compact and sophisticated double wishbone suspension design has been used in Honda automobiles for some time, all of the new Accord's suspension components have been redesigned in consideration of the car's increased weight and size. Additionally, the basic design has been considerable refined. The suspension stroke is increased, toe-angle change is reduced, and the amount of alignment deviation during the suspension stroke is decreased.

The front roll center is lowered, reducing horizontal movement and stabilizing the ride. The king pin center is offset by 7.3 mm (0.29in.) to minimize steering disturbance. Bushing compliance is increased to reduce harshness and improve ride comfort and spring rate and size are increased and front shock absorbers have larger diamter pistons and higher load capacity.

DOUBLE WISHBONE FRONT SUSPENSION
The Accord's double wishbone front suspension system uses two arms, or wishbones, of different lengths to minimize changes in track and camber, and improve anti-dive characteristics. Its new design permits 25 mm (nearly an inch) more suspension travel-lO mm bump, 15 mm rebound-to increase ride comfort.

The main front suspension components are an upper lateral arm, a lower trailing compliance link and a lower lateral arm. The upper arm controls vertical wheel motion, permitting nearly vertical spring and damper travel and freeing the spring/shock strut from any wheel locating functions, which reduces shock friction and improves ride. The upper and lower control arms are widely separated for better load dispersion and improved anti-dive control, and the suspension geometry is set to minimize camber change for more precise wheel control. A front stabilizer bar contributes to flat cornering.

DOUBLE WISHBONE REAR SUSPENSION
The Accord's rear suspension is located by pivoting lower compliance trailing arms, lower lateral links, and upper lateral arms, which pivot behind the shock absorber and spring unit. Both the upper and lower arms have been lengthened, increasing suspension travel by 40 mm (1.57 in.)-15 mm bump and 25 mm rebound-to reduce harshness and improve ride.

Rear suspension geometry incorporates a built-in camber change to help improve cornering power and reduce rear-body lift during braking. On EX versions, a stabilizer bar further contributes to flat cornering.

VARIABLE-ASSIST POWER STEERING
To keep the steering force appropriate to the driving mode, the Accord has a new speed-sensitive, variable-assist power steering system. It automatically and progressively adjusts the amount of assistance, according to the vehicle speed, maintaining a high degree of road feel.

Sensors within the system monitor speed and vary assistance accordingly. At very low speeds, such as when parking or driving in city traffic, assistance is the greatest. As speed increases, it decreases at a linear rate, dropping to minimum assistance. The transition is so gradual that the driver is not aware of the change, and the effort needed for steering remains at a comfortable level.

BRAKING SYSTEM
Along with the new Accord's larger wheels, there are larger brakes: 260 mm (10.2 in.) ventilated discs in front, and 220 mm (8.7 in.) drum brakes in the rear. They are power assisted by a new tandem vacuum booster which has a 7-inch and an 8-inch chamber for improved brake feel. More efficient and compact than the 9-inch, single chamber booster it replaces, the new booster keeps pedal effort low yet provides a firm feel.

WHEELS AND TIRES
The wheel and tire size of the new Accord is increased from 13.0 x 5.0 to 14.0 x 5.5 inches on DX and LX versions-which are equipped with P185/70-R14 87S steel-belted radials mounted on styled steel wheels. LX versions are equipped with Michelin LX1 tires. Wheel size on EX models is increased to 5.5JJx15 inches and these Accords are fitted with 195/60-RiS 87H Michelin MXV3 steel-belted radials mounted on distinctive alloy wheels.

1990 Honda Accord - Drivetrain

OVERVIEW/DESIGN OBJECTIVES
The 1990 Honda Accord's 2.2 liter, fuel-injected, 16-valve engine is an entirely new design. It has more horsepower and torque for improved performance, and incorporates innovative Honda technology that allows it to run smoothly and quietly.

The engine's high output is due, in part, to its increased displacement This is a dependable method of raising power but it presents significant design challenges in four-cylinder, in-line engines because of an inherent imbalance that causes vibrations to increase as displacement increases. To counteract these tendencies, Honda engineers pursued several strategies, including the design of an efficient secondary balancer system that differs conceptually from other designs based on the same principle.

To complement the engine's power curves and increased output, both automatic and manual transmission are newly designed. The automatic is based on a compact, three-shaft configuration. It is electronically controlled with a lockup torque converter and a Sport mode for spirited driving. The 5-speed manual transmission has been redesigned to increase rigidity and strength, and reduce noise and vibration.

The Accord's front-wheel-drive system is also redesigned in consideration of the engine's greater power and the car's larger size.

ENGINE
The Accord's new 2.2 liter in-line, fuel-injected, four-cylinder engine uses a single overhead camshaft and four valves per cylinder. It is compact and light weight with an aluminum block and cylinder head. The engine is transversely located and angled 10 degrees to the rear (as opposed to 15 degrees to the front in the 1989 Accord) for improved weight distribution and better under-hood packaging.

Though the engine is an undersquare design-with an 85 mm (3.35 in.) bore and a 95 mm (3.74 in.) stroke-its bore is relatively large, which permits the use of larger intake and exhaust valves. The engine's cam timing, induction and ignition systems are tuned to produce a steep, smooth horsepower curve with a wide torque band.

Among the engine's key features are a Honda-developed secondary balancer system that substantially reduces vibration, a tuned intake manifold with Multi-Point, Programmed Fuel Injection (PGM-Fl), and a fully electronic ignition system. A three-way catalyst provides emission control.

The output of the engine in Accord DX and LX models is 125 horsepower at 5200 rpm and 136.7 lb-ft. of torque at 4000 rpm. The engine in EX models is rated at 130 horsepower at 5200 rpm and 141.8 lb.-ft. of torque at 4000 rpm. The difference is attributable to the EX's four-into-two exhaust manifold and dual exhaust system, otherwise the engines are nearly identical.

SECONDARY BALANCER SYSTEM
To meet the power and performance criteria set for the new Accord, while improving its comfort and drivability, Honda engineers designed a secondary balancer system that significantly reduces vibration. It incorporates two unbalanced shafts turning in opposite directions at twice the crankshaft speed to dampen inertial forces.

The balance shafts are supported by three bearings and are crankshaft-driven by a toothed belt. A small gearbox is used to reverse the direction of the shaft that spins opposite the crankshaft. Both shafts are timed to rotate so that their imbalance is in direct opposition to the inertial forces created by the movement of the pistons and connecting rods. The two forces cancel each other, and the vibration level is cut to as much as one-tenth of what it would be without balance shafts.

The key difference between the Honda-designed system and other balance shaft layouts is the placement of the shafts. In most other systems the shafts are offset-the one that rotates in the same direction as the crankshaft is on a higher plane than the other shaft. Honda's design places the shafts on the same plane, 81 mm (3.19 in.) above the horizontal crankshaft centerline. The location of these shafts relative to each other determines the rpm range in which they are most effective. In other systems, this is the high-rpm range; in the Honda system it is in the mid- to high-range where most normal driving occurs.

ELECTRONICALLY CONTROLLED ENGINE MOUNT
In Accords equipped with automatic transmissions, a dual phase, electronically controlled rear engine mount smooths low-frequency vibration which can occur under high-load, low engine speed conditions, such as idling in gear with the air conditioner running.

The mount contains two fluid-filled chambers separated by a barrel valve. At low engine speeds, the valve is open so the full volume of both chambers can dampen the vibration. At 850 rpm, sensed by a computer which monitors ignition pulse, the valve is closed by a vacuum actuator, which takes one chamber out of the loop and makes the mount firmer.

ENGINE BLOCK
The cylinder block is die-cast aluminum alloy with integral cast iron cylinders. It saves 12.0 kg. (26.4 lbs.) versus the 1989 Accord's cast iron block. For added rigidity, it has a deep skirt which extends 50 mm (1.96 in.) below the crankshaft center line.

This block has the largest bore of any Honda 4-cylinder engine to date-85 mm (3.35 in.)-and a 95 mm (3.74 in.) stroke for a displacement of 2156cc (131.6 cu. in.). It uses five main bearings to support a forged steel crankshaft which carries forged steel connecting rods and forged aluminum pistons.

Mounting points for crank-driven components are on the front-facing side of the block which improves both under-hood packaging and maintenance access.

Particular attention was paid to reducing inertial mass and improving the vibration damping characteristics of rotating components by redesigning the torsional damper and pulleys for the camshaft and accessory drives.

CYLINDER HEAD
The Accord's engine uses an aluminum cylinder head with a flow-through design, large intake and exhaust ports, single overhead camshaft, and four valves-two intake and two exhaust-per cylinder. Its combustion chamber is of the highly efficient hemispherical design, modified to a pent roof shape. The compression is 8.8:1 and the chamber has a centrally located spark plug for even flame propagation.

The engine's increased bore permits the use of large valves- 34 mm (1.338 in.) intake and 29 mm (1.141 in.) exhaust-which further increase power and torque. By comparison, the new engine has 13.7 percent more intake valve area, and 19.0 percent more exhaust valve area than the three-valve 1989 Accord engine, even though it is only 9 percent larger in displacement.

The valves are at an included angle of 51 degrees and are actuated by forged steel rocker arms that pivot on two shafts located on each side of the camshaft, which is driven by a toothed belt.

INDUCTION SYSTEM
To raise low- and mid-range torque, the Accord's intake manifold uses long-430 mm (16.9 in.)-equal-length runners to increase intake velocity and pack a denser fuel/air charge into the combustion chamber. It is tuned to complement Honda's Multi-Point Programmed Fuel Injection (PGM-FI) system, which uses a microprocessor to control the fuel/air ratio and injection timing.

1990 ACCORD DRIVE TRAIN
The microprocessor monitors seven engine functions: throttle angle, crankshaft angle, coolant temperature, intake air temperature, manifold air pressure, atmospheric pressure, and exhaust gas oxygen content. It analyzes this information and continuously adjusts the injection system to maintain the optimum fuel/air ratio.

To reduce noise, the induction system has a two-stage air pre-induction system with two ducts connecting the air cleaner to the manifold. Since less air is required at low rpm, only one duct is open, keeping the air flow noise to a minimum. As engine speed increases, the second duct opens. Whatever additional noise this may create is not apparent to the driver because of the higher ambient noise levels that normally occur as engine speed increases.

IGNITION SYSTEM
The Accord's fully electronic ignition system is contained entirely within the distributor. This single, compact unit includes the coil and eliminates the wiring necessary with separate components. It is lighter, more space efficient and has fewer connections, which improves the system's reliability.

ELECTRONIC ENGINE MANAGEMENT SYSTEMS
The Accord uses two ECUs (Electronic Control Units), one for the engine and one for the automatic transmission. The engine ECU monitors sensors which read water temperature, air temperature, throttle position, exhaust oxygen, engine speed, air pressure, manifold pressure, top dead center and crankshaft angle. It processes this information and adjusts the air-fuel ratio, injection and ignition timing for the best possible efficiency and performance.

The automatic transmission ECU is programmed to control shift points and lockup according to the shift position and driving conditions.

MANUAL TRANSMISSION
The 1990 Accord has a new 5-speed manual transmission that's more rigid and durable to match the engine's increased power and torque. It has been refined to improve drivability and reduce noise and harshness. This was done by optimizing gear dimensions, improving the resonance characteristics of the housing, and using more precise parts manufacturing and assembly.

A spring-dampened clutch is actuated hydraulically and the shift mechanism is designed for short throws and positive engagement.

AUTOMATIC TRANSMISSION
The Accord's 4-speed automatic transmission is a new design that's compact, smooth-shifting and efficient. It is computer controlled and has a driver-selectable Sport mode, lockup torque converter and seven shift positions: Park, Reverse, Neutral, D4 and D3 with Sport mode, Second and First (Low-Hold).

Unlike most conventional transmissions, it uses three parallel axis shafts-a main shaft, a counter shaft and an additional secondary shaft-instead of two shafts. The unit is barely larger than a normal transmission (it is just 2 mm longer than the 1989 two-shaft automatic) yet permits the use of a fifth clutch so the transmission can be held in low gear until the driver moves the shift lever. This "low-hold" feature is useful when low-speed power or engine braking is needed, as when pulling a boat trailer out of the water or descending very steep inclines.

To improve efficiency, the new transmission has a lockup torque converter that engages in second, third and fourth gear when maintaining steady speeds, and third and fourth to provide engine braking when decelerating.

For smoother shifts, the transmission ECU signals the engine ECU to retard the spark between shifts, momentarily lowering engine torque, so that gear-change shock is reduced. For smoothing the upshift from third to fourth, and downshifts from fourth to third or second, there's an accumulator control system in the shift valve that maintains steadier hydraulic pressure and makes the shifts less abrupt.

The driver-selectable Sport mode is designed for sporty performance at partial throttle levels. With the shift lever in the D3 position, pushing the Sport mode switch on the shifter directs the transmission to shift at higher rpm points when going from first to second and second to third. Using Sport mode in the D4 position extends the function to the third-to-fourth shift. The Sport mode increases responsiveness and is useful on long grades to keep the transmission from "hunting" for gear ratios.

FRONT-WHEEL DRIVE
As with the engine and transmission, the Accord's drive components have been redesigned to complement its increased size and power. Also, important changes were made in the drive system geometry. Because the layouts of the new automatic and manual transmissions place the inboard constant velocity joints lower, the angle between the inboard and outboard joints is decreased, which helps to reduce torque steer.

Accords equipped with a manual transmission use equal-length halfshafts, which also helps reduce torque steer, and flat-roller, tripod constant-velocity joints. These were developed by Honda and reduce vibration at extreme joint angles. Unlike conventional joints, they incorporate roller bearings with a flatter surface and guide plates which maintain the bearing's alignment as it responds to axle motion. In bearings without these features, the maximum angle possible before friction and vibration sets in is six degrees; the newly designed joints permit an angle of 12 degrees.