Pontiac Fiero
Manufacturer	Pontiac
Parent company	General Motors
Production	1984–1988
Successor	Pontiac Solstice
Class	Sports car
Body style	2-door notchback 2-door fastback
Layout	MR layout
Platform	GM P platform
Engine	2.5 L Iron Duke I4 2.8 L
Transmission	4-speed manual 5-speed Isuzu &  manual 3-speed TH-125 automatic
Wheelbase	93.40 in.
Length	4072 mm (160.3 in)
Width	1750 mm (68.9 in)
Height	1191 mm (46.9 in)
Curb weight	1176 kg (2590 lb) to 1265 kg (2790 lb)
Similar	Fiat X1/9 Toyota MR2 Matra Murena
Designer	Hulki Aldikacti

The Pontiac Fiero is a mid-engined sports car that was built by the Pontiac division of General Motors from 1984 to 1988. Today, the car has a large cult following, making it a prime example of a cult car.

Brief history

Once a dream originally envisioned by John DeLorean, inspired by his Pontiac Banshee prototype, the Fiero -- meaning "proud" in Italian -- was finally designed by Hulki Aldikacti as a Pontiac sports car. Other names considered were Sprint, P3000, Pegasus, Fiamma, Sunfire, and Firebird XP. Because of a "cool" reception by GM management and accountants, it was finally marketed to GM as a fuel-efficient commuter car. The public, however, had other ideas for the only mid-engined car ever mass produced in North America. The Fiero was also the first 2-seater Pontiac made since the 1926 to 1938 coupes, and until the 2006 introduction of the Pontiac Solstice. The sports car potential of this car was greatly reduced due to cost-cutting however, and came under fire from critics because its publicity did not match its initial performance. Though originally designed with its own suspension and brakes, ultimately off-the-shelf components were used, which severely limited the Fiero's performance envelope.

By the end of production, the Fiero had received the original suspension design but kept a limited offering of engines — the use of turbochargers or the newer DOHC straight-4 engines, never made it to production. Officially, production ended because of insufficient profits. Budget constraints on Pontiac forced them to borrow parts from other models rather than use the suspension originally designed by the engineers. For example, some of the front suspension was taken from the Chevrolet Chevette's [1] double A-arm design, allowing the wider and low-slung Fiero to handle exceptionally well (though at a cost; the Fiero shared front wheel bearings with the Chevette, and the Fiero's greater weight, wider tires and tendency to be driven like a performance car resulted in short bearing life). On the other hand, Chevette enthusiasts routinely upgraded their notoriously undersized brakes and rotors using Fiero parts. The rear suspension and base drivetrain was almost identical to the front end of GM X-body cars like the Chevrolet Citation and Pontiac Phoenix - the Fiero even included rear tie-rod ends for alignment, though they would have been used for steering had that particular assembly been used in an X-car.

An interesting article was published in the May 1984 Car & Driver about Henry "Smokey" Yunick and his Hot Vapor Fiero. Smokey Yunick reportedly produced 250 HP from the GM 151 2.5 4 cylinder engine using heated fuel pumped through a turbine "homogenizer" and an exhaust-heated "heat exchanger". In this instance, the HP was reportedly doubled as well as the fuel economy. A 14 second car became a 5.9 second car. This concept is based on the theory of the adiabatic engine, where no heat is gained or lost during the process.

 

Engine fire reputation

The fires, which affected almost exclusively the 2.5 L engine, and mostly '84 models at that, were due in some cases to the engine wiring harness being located above the exhaust manifold, with a notoriously leaky valve cover in between. Most valve covers leak oil onto the exhaust manifold eventually. If the wiring falls onto the exhaust manifold, or somehow shorts against it, it often ignites the oil that has leaked onto the back of the engine. Also, the 1984 model had a magnesium grille over this area. In later models, this was corrected to some degree with much better heat shielding. This issue was with the 1984 models.

The primary cause of engine fires was poorly cast connecting rods failing under infrequent oil changes. The faulty connecting rods were produced in GM's Saginaw plant. As the "Iron Duke" engine was a relatively long-stroke four cylinder engine, it produced most of its power in the low revolution ranges. In most vehicles, this is not a problem, but there were two schools of thought concerning the Fiero.

One theory is that the sports car styling attracted buyers who would drive the car hard, most notedly over-revving the engine. The long-stroke geometry of the Iron Duke makes it less suitable for high RPM operation, most noted by GM calibrating the tachometer redline at 5000 RPM. The reason GM designed this engine to produce the power in the lower RPM band is because the car was originally intended as an economy commuter that didn't look like the other boxes on the dealership lots at the time.

Another factor was the 3 quart capacity oil pan, coupled with the then-stock specified AC-Delco PF-47 oil filter, and the leaky valve cover gasket. If proper oil level was not maintained, the bearings would seize, snapping the porus castings of the connecting rods resulting with punched holes in the engine block, thus spraying oil onto hot exhaust components where it could ignite.

However, most vehicles existing today have been serviced by GM during one of the safety recalls on the car. On the fire-related recalls, shields and drip-trays were added to prevent leaking fluids from contacting hot surfaces. The presence of drip shields between the engine block and the exhaust manifold are a good clue that the car was retrofitted. The addition of the longer AC Delco PF52 oil filter, commonly found on other models, like the V6 Chevrolet Camaro and Pontiac Firebird, as well as the Chevrolet Astro Van, added extra oil capacity to the oiling system.

 

Cooling system issues

With the mid-mounted engine and long pipes carrying coolant to the front-mounted radiator, the Fiero was also prone to overheating if the cooling system had not been properly filled. Simply pouring coolant into the thermostat housing (on the engine) would leave a large bubble in the radiator, while adding coolant to the radiator would cause a large bubble in the engine's coolant passages. Proper procedure (filling the thermostat housing, then burping the bubble out of the radiator by cracking open radiator cap until coolant exits) must be followed in order to ensure an air-free cooling system.

A second problem has become common as more Fieros are being serviced by shops unfamiliar with their design. The under-body coolant tubes are positioned in such a way that a casual glance beneath the car will not suggest their fragility. As a result, many have been crushed by the shop lifts, resulting in a near complete lack of engine cooling. The age of the car means that even GM dealerships may be unaware of the proper jacking methods.

 

Suspension design

The front end of the car is a wider direct derivative of the Chevette. A double A-arm (or double wishbone) design common prior to MacPherson struts, it has naturally good geometry. But it also has four ball joints on the front and another four tie rod ends. The tie-rods allow toe-in/out adjustability. Minimal camber adjustments exist on 84-87 models without an after-market upgrade available from MOOG that replaces the upper ball joints with slotted mounting points units. The joints have typical grease fittings for regular lubrication typical on pre-2000 autos.

The rear suspension is essentially a GM X-car's front suspension moved to the rear of the Fiero. The uppers are top-plates and MacPherson struts, while the lowers are attached with ball joints. In lieu of the steering rack which would have been installed in an X-car, tie rod ends are attached to the engine cradle and used to align the rear wheels.

The overall design provides an extremely good independent suspension to all wheels, built with GM's off-the-shelf parts. Maintenance is required on most vehicles, as they predate modern sealed ball joints. Should one ball joint require replacement (evidenced by any detectable wobble in a ball joint when the wheel is in the air), it is prudent to replace all six ball joints and all eight tie rod ends in the car; otherwise, the requisite four wheel alignment would be a waste of money after the inevitable and imminent replacement of the next ball joint.

With the 1988 model year came a completely new front and rear suspension with vented disc brakes at all four corners- what Pontiac's engineers had planned for the car to have from the beginning. The front suspension geometry was changed to decrease the scrub radius thus decreasing steering effort without adding a bulky power steering system. The camber curve was also much improved, the dampers are moved inside the coil springs, and new sealed bearing/hub units were used (unique to the 1988 Fiero, to the dismay of many owners seeking repair or restoration). The rear suspension featured multi-link (two lateral links and one trailing arm) MacPherson strut suspension, and the bump steer experienced with the earlier suspension design was fixed. The brakes were also upgraded to 10.5" vented rotors on the front and rear with an improved slide caliper design. The Fiero Formula (new for 1988) and Fiero GT models also received a rear swaybar.

An important note is that the 84-87 frames will accept a 1988 rear cradle. However the struts must be replaced with a narrower diameter Carrera coil-over unit with a steel tube extension and offset mounting plates added to replace the MacPherson strut unit. Thus yielding a larger, 84-87 engine compartment with the tremendous ride-quality benefits of the 1988 suspension.

In the August 1985 issue of Road & Track, the Fiero was tested against 6 other sports cars. The slalom results (MPH): Honda Civic CRX Si: 62.5 Toyota MR2: 61.6 Pontiac Fiero: 61.5 Alfa Romeo Graduate: 58.4 Bertone X1/9: 58.3 Mazda RX-7 GSL: 57.2

 

Today

Currently the Fiero has a strong following of owners and customizers. Because of an abundance of replacement parts available from other General Motors vehicles, there are many upgrades that can be done to improve performance and reliability of the cars. Additionally, a multitude of different General Motors engines have been installed by enthusiasts, from the Quad-4 engine to the Chevrolet small-block V8.

The Fiero 2M4 (2-seat, Mid-engine, 4-cylinder) was on Car and Driver magazine's Ten Best list for 1984. The 1984 Fiero was the Official Pace Car of the Indianapolis 500 for 1984, beating out the new 1984 Corvette for the honor.

A large following of owners still exists with many web pages, groups, and clubs devoted to the car, and the basic chassis is commonly used as a kit-car platform from wild custom rebodies to Ferrari F355 replicas.

 

Transmissions

Automatics

All automatic-equipped Fieros were equipped with the three-speed TH-125 with torque converter lockup.

Automatic transmission final drive ratios:

• I4
  • 1984-1986: 3.18 (RPO "F75")
  • 1987-1988: 2.84 (RPO "?")
• V6
  • 1985-1986: 3.06 (RPO "?")
  • 1987-1988: 3.33 (RPO "GX3")

 

4-speed manual

All 4-speed manual transmissions were built at the Muncie, Indiana Allison plant. The 1984 production line saw two transmissions, a performance 4-speed with a final drive ratio of 4.10, and an economy 4-speed with a final drive ratio of 3.32. The V6 on the 1985 model and part of the 1986 production year came with a 4-speed with a final drive ratio of 3.65.

 

5-speed manual

Isuzu and Muncie (Getrag)- 5-speed transmissions were available, depending on model and equipment beginning in 1985 for the Isuzu 5-speed which came on 4 cylinder cars and in 1986 for the Muncie 5-speed which came on V-6 equipped cars. The Getrag 282 5-speed is sometimes referred to as the Muncie 282 or the Muncie Getrag 282, as the design was licensed to General Motors for manufacture by Muncie (Getrag never built the 282). This Muncie transmission is the stronger unit, designed for use with the higher output of the V-6.

 

Manual transmission gear ratios

Year	Style	Code	Axle	1st	2nd	3rd	4th	5th	rev.
1984	econo 4 speed	MY8	3.32	3.53	1.95	1.24	0.73	—	3.42
1984	perf 4 speed	M19	4.10	3.53	1.95	1.24	0.81	—	3.42
1985	V6/4-speed	M17	3.65	3.31	1.95	1.24	0.81	—	3.42
1985	I4/5-speed	MT2	3.35	3.73	2.04	1.45	1.03	0.74	3.50
1986	V6 4 speed	M17	3.65	3.31	1.95	1.24	0.81	—	3.42
1986	V6 5 speed	MG2	3.61	3.50	2.05	1.38	0.94	0.72	3.41
1988	I4/5-speed	MT2	3.35	3.73	2.04	1.45	1.03	0.74	3.50
1988	V6/5-speed	MG2	3.61	3.50	2.05	1.38	0.94	0.72	3.41

 

Production years

 

1984

1984 was the first production year for the Pontiac Fiero, which began production in August 1983 for the 1984 model year. In an effort to sell the car as being economically sensible, GM equipped and sold the Fiero as a commuter car but the marketing build up leading to initial release indicated anything but a regular commuter car. The car also proved uncomfortable for some drivers because of the lack of power steering.

The 1984 was the only year in which the Limited "Indy Pace Car" edition, consisting of an Indianapolis 500-themed option package on SE-model vehicles, was offered. Approximately 2,000 of these vehicles were sold. The Indy had aero body cladding and new front and rear fascias that would be used on the 1985 GT. Only the underpowered 4-cylinder engine was available (though a few prototypes could be seen driving around the Greater Detroit area with a unique periscope-style inlet sprouting from the engine compartment and curving up and over the roof. This "periscope" style inlet was used on the actual Indy Pace Car Fieros that at the 1984 Indianapolis 500. This inlet scoop, and the 2.5 liter Super Duty engine that they fed were not available on the production model pace car replicas.

1984 production

VIN	Style	Cars produced
1G2AE37RxEPxxxxxx	Fiero	7,099
1G2AM37RXEPxxxxxx	Fiero Sport	62,070
1G2AF37RxEPxxxxxx	Fiero SE or Indy	65,671
Total production		136,840

 

1985

In 1985, the problem with insufficient power was first addressed, much to the satisfaction of the general public. A Chevrolet 2.8 L V6 engine rated at 140 hp (104 kW) was put into the car, satisfying most critics of the base engine. The High Output V6 was paired with a modified Muncie 4-speed transmission. The 4-cylinder engine (known as the "Iron Duke") was now paired with the Japanese-designed Isuzu 5-speed (also produced at the Muncie, Indiana plant).

1985 production

VIN	Type	Cars produced
1G2PE37R#FP2#####	Fiero	5,280
1G2PM37R#FP2#####	Fiero Sport	23,823
1G2PF37R#FP2#####	Fiero SE (I4)	24,724
1G2PF379#FP2#####	Fiero SE (V6)
1G2PG379#FP2#####	Fiero GT	22,534
Total production		76,371

 

1986

1986 was the first year the fastback roofline was offered. Though originally conceived by Pontiac insiders as a new model, possibly called the "GTP" or "GTU," it has been said that GM management at the time felt that using "GTP" or "GTU" suggested a racing car and thusly an image they did not want to promote. Individuals present at the unveiling of the new fastback roof style at a GM test track actually thought it was a new Corvette at first. But this new body style simply became the GT model for 1986 while the old 1985 GT body style became the SE model. Also offered late in the production year was a 5-speed Muncie-Getrag transmission (coupled only to the V6 engines). Models equipped with the 4-cylinder engine remained largely unchanged. The clutch hydraulic systems were redesigned with new master and slave cylinders.

1986 production

VIN	Type	Cars produced
1G2PE37R#GP2#####	Fiero	9,143
1G2PM37R#GP2#####	Fiero Sport	24,866
1G2PF37R#GP2#####	Fiero SE (I4)	32,305
1G2PF379#GP2#####	Fiero SE (V6)
1G2PG379#GP2#####	Fiero GT	17,660
Total production		83,974

 

1987

1987 saw changes to the front and rear fascias on the "base coupe" with the SE & GT models keeping the same "Aero" nose. The new non-aero noses lost the black bumper chunks of the earlier models and had a smoother look. The 4-cylinder's power rating increased to 98 hp (73 kW) with some major modifications which included a roller cam, redesigned intake manifold, distributorless ignition system, open combustion chamber cylinder head and upgraded throttle-body fuel injection system. This was the last year for the spin-on oil filter on the 4-cylinder. The car was offered in Medium Metallic Blue and replacing the ribbed black moulding was the round style found on the GT models. As a side note, the SE models retained the ribbed moulding, and added the aero nose found on the GT. Redesigned headlight motors appeared in 1987. Additionally, starting with the 1987 model Pontiac dealerships offered an upgrade in the form of an "option" that changed the original body to a Ferrari-type body, called the Fiero Mera. While technically a "kit", the change in body style was offered only on new Fieros and is considered a class of car in its own right. There was a limited production of Fiero Meras made however, as the company that produced them, Corporate Concepts, was sued by Ferrari and ordered to stop.

1987 production

VIN	Type	Cars produced
1G2PE11R#HP2#####	Fiero	23,603
1G2PM11R#HP2#####	Fiero Sport	3,135
1G2PF11R#HP2#####	Fiero SE (I4)	3,875
1G2PF119#HP2#####	Fiero SE (V6)
1G2PG119#HP2#####	Fiero GT	15,968
Total production		46,581

 

1988

The 1988 Fiero brought a new suspension design, thought by many to have a striking resemblance to those designed by Lotus, which at the time, was about to be acquired by General Motors. The suspension was never a Lotus design though - it was the suspension the Pontiac engineers had designed in the beginning. The 4-cylinder engine received an in-pan oil filter element and balance shaft and a more powerful V6 was available. A "Formula" option was added, which offered many of the GT features with the standard coupe body. 1988 marked the end of production for the Fiero, and ironically is also considered to be the best Fiero produced. Improvements to suspension, brakes, steering, and improvements to both the four-cylinder and V6 engines took the car to a level far beyond the 1984 model that had received much criticism. Also 1988 was the only year T-tops were an option through dealerships, and the only year a yellow exterior color was available from factory.