Fiero Info

The Pontiac Fiero is a mid-engined sports car built by Pontiac from 1983 to 1988. The Fiero was designed by George Milidrag and Hulki Aldikacti as a sports car. The Fiero was the first two-seater Pontiac since the 1926 to 1938 coupes, and also the first and only mass-produced mid-engine sports car by a U.S. manufacturer. Many technologies incorporated in the Fiero design such as plastic body panels were radical for their time. Other features included hidden headlamps and, initially, integrated stereo speakers within the driver and passenger headrests.

A total of 370,168 Fieros were produced over the relatively short production run of five years; by comparison, 163,000 Toyota MR2s were sold in their first five years. At the time, its reputation suffered from criticisms over performance, reliability and safety issues.

The word fiero means “very proud” in Italian, and “wild”, “fierce”, or “ferocious” in Spanish. Alternative names considered for the car were Sprint (which ended up on a Chevrolet car instead), P3000, Pegasus, Fiamma, Sunfire (a name which would later be applied to another car), and Firebird XP. The Fiero 2M4 (two-seat, mid-engine, four-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 Chevrolet Corvette for the honor.


The Fiero was conceived as a small, two-seat sports car with all new suspension and V6 engine. While General Motors management and accountants were opposed to investing in a second two-seater sports car that might compete with the Corvette, they perceived the oil crisis as a market opportunity for a fuel-efficient sporty commuter car. To this end, the Fiero was re-designed to use a fuel efficient version of GM’s 2.5 L (150 cu in) four-cylinder “Iron Duke” engine capable of 31 mpg-US (7.6 L/100 km; 37 mpg-imp) in the city and 50 mpg-US (4.7 L/100 km; 60 mpg-imp) on the highway with the economy-ratio transmission option. These figures are U.S. Environmental Protection Agency test-circuit results, published by Pontiac, and confirmed from multiple sources. It was impressive mileage for a 2.5 L engine of the period, and still good by today’s standards, but the three-speed automatic reduced highway mileage to only 32 mpg-US (7.4 L/100 km; 38 mpg-imp). With respect to fuel economy, the Fiero was intended to appeal to a market niche for which the Corvette with its V8 engine was unsuitable.

A mid-engine layout was originally chosen as a way to reduce both aerodynamic drag and vehicle weight to improve fuel efficiency, and also for its handling, traction, and braking benefits. However, the sports car potential of the mid-engine layout was not realized when the Fiero debuted. As a cost-saving measure commonly employed at GM, the tires, brakes, and suspension components were carried over from other GM economy cars (like the X and T platforms). As a result, the handling and cornering abilities of the initial Fiero were merely on par with other contemporary sporty coupes (Road & Track 1985). Additionally, the Iron Duke I4 motor, which was designed for optimal running at low RPM due to its long stroke, was unsuited to drivers who purchased the Fiero expecting a quick, high-revving motor more in keeping with the design of the car. As drivers attempted to frequently run the engine at greater RPM than it was designed for, the engines experienced a number of reliability problems and breakdowns were frequent.

The public had high expectations for the Fiero with its mid-engine layout and aggressive styling, which resembled exotic mid-engine sports cars like the Ferrari 308GTB. While initially garnering good reviews for its handling (Motor Trend 1984), the Fiero soon received negative reviews from other automotive critics who expected higher performance from a mid-engine two-seater. Despite the critical press, the Fiero sold well and although Pontiac operated three shifts at the factory during 1984, they could not keep up with initial demand.

The sharing of suspension and other components with other GM cars meant the rear suspension and powertrain was virtually identical to that of the Citation and Pontiac Phoenix; the Fiero even included rear tie rod ends attached to a “steering knuckle”, although these were hard-mounted to the engine cradle and only used for maintaining the rear tire alignment. The front suspension was derived from the Chevette, and Chevette enthusiasts found that they could upgrade their undersized front brakes and rotors using Fiero parts.

By 1985, the oil crisis was long past and demand developed for a Fiero having more engine power and better sports car performance. Pontiac responded by introducing the GT model which included upgraded suspension tuning, wider tires, and a V6 engine having 43 hp (32 kW) more than the base four-cylinder.

Finally, in 1988, numerous changes were made to the Fiero to bring it in line with its original design. The most significant was a completely redesigned suspension (and parts of the space frame) to realize the potential of the mid-engine layout. The unique suspension included new two-piece brake calipers and upgraded brake rotors. These had been part of Fiero’s initial design, but cost-cutting kept them from being implemented sooner. The available I4 and V6 engines benefited from evolutionary improvements, but the planned availability of turbochargers and newer DOHC engines did not happen before production stopped.

In spite of the much-improved car which finally had realized its potential after years of mismanagement, GM ended production after the 1988 model year due to declining sales figures. Bad press and consumer sentiment frequently cited heavy media coverage of Fiero engine fires, as well as the poor reliability and performance of the 1984-1987 models.


The Fiero turned out to be an unusual design for GM, which stood out from the rest of their product lines. The company had rejected development of a sporty, two-seater Pontiac since the late 1960s, as they believed it would steal sales from the Corvette. However, young Pontiac engineers in 1978 were able to sell the Fiero concept to the corporation as a fuel-efficient four-cylinder “commuter car” that just happened to have two seats, rather than a muscle car. When the engineers brought back a running prototype in less than six months, corporate bought it. However, the budget for the car, from design to building the machines for making the parts, was 400 million dollars, just a fraction of what GM generally spent on bringing a typical prototype car into production. Pontiac assigned oversight of the Fiero to Hulki Aldikacti, a Turkish émigré with a master’s degree in mechanical engineering from the University of Michigan and an MBA from Michigan State University along with nearly 22 years of experience.

Aldikacti’s initial challenge was with GM’s corporate structure, which split its engineers into two categories: the car engineers who would create blueprints for the car, and manufacturing engineers who would work out the fabrication and assembly issues. Fiero blueprints traveled back and forth between the two engineering branches, using up time and money. Aldikacti was forced to sit the two teams of engineers down next to one another, allowing for no excuses to why there was “no build” after his design was done. Many modifications in the Fiero’s production needed to be made; for instance, despite his long-standing interest in manufacturing body panels from plastic, Aldikacti consented to metal body pieces, the dies for which were much less costly.

As the prototypes took shape, the exterior lines resembled more of a Ferrari or Porsche than a typical GM car, but the tight budget was taking its toll on the design, particularly on Aldikacti’s dream of a high performance, aluminum-block V6; the cost of developing a new engine would be more than the production of the whole car itself. Instead, Aldikacti was forced to settle for the already manufactured four-cylinder engine GM produced for the Pontiac, the “Iron Duke,” nicknamed for its heavy iron block. This engine was too blocky to fit into the tiny car so it was equipped with a smaller oil pan, causing the engine to always run a quart low.

Aldikacti’s unorthodox design methods and personal manner made him unpopular to most of GM’s bureaucracy. Three times he was told by counterparts at other GM divisions that his project had been cancelled by corporate management. However, the Fiero project was kept alive at the wishes of certain high-ranked defenders, chief among them William Hoglund, who took over Pontiac in 1980. Hoglund took the reins as the division was suffering from the loss of their hot rods in the late 1970s; Pontiac’s cars were said to be bland, outdated, and what customers of the past would buy. In 1983 Hoglund told his top three dozen staffers that Pontiac would rebuild itself with cars that were “exciting” and “different.” These terms only described one of Pontiac’s cars in their current lineup, Aldikacti’s “commuter car.” In order to build the 100,000 cars a year Hoglund’s marketing team committed to sell, Hoglund negotiated a deal to reopen a plant once shut down in the heart of Pontiac, Michigan. He and his staff wanted to prove that cooperation between management and labor could be solved without the use of robots on the assembly line, which GM’s top executives wanted to use. Hoglund allowed hourly workers to name Aldikacti’s car; “Fiero” was their choice.

Production years


1984 Fiero SE

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

At the beginning of production the Fiero was only available in Red (M71) and White (M40) with Black (M41) and Light Gray Metallic (M14) introduced later, the paint shop was only able to handle four different colors at a time. All 1984s came with the same 2.5L I4.

Although sales literature listed only two models available in 1984, there were at least three models available with different option packages. There was the Fiero Coupe, the Sport Coupe and the SE. The Fiero Coupe, also called “Fuel Economy Leader”, came with the MY-8 4-speed manual transaxle that had a 0.73 overdrive top gear along with a high mpg 3.32:1 axel ratio. This gave it an EPA highway/city rating of 50/31 mpg. Airconditioning and automatic transaxle could not be order. The starting price for the Fiero Coupe was $7999. The Fiero Sport Coupe, also referred to as the “base car”, came with the M-19 4-speed manual with a 0.81 top gear along with 4.10:1 differential, giving it better acceleration at the cost of fuel economy, 42/26 mpg. An automatic 3-speed transmission, MD-9 ydramtic 125-C, was available along with A/C. The starting price was $8499 for the Sport Coupe. The top model was the Fiero SE, starting at $9599, it included the WS-6 handling package along with other trim upgrades.

Fiero marketing included title sponsorship of Daryl Hall & John Oates tour supporting the release of their “Big Bam Boom” album. From November 1984 through 1985, each tour venue had Fiero banners and signage above the main stage, new Fieros on display, and Pontiac dealer ticket giveaways. Sales managers at Pontiac dealerships also received a limited edition “Pontiac Fiero Presents Daryl Hall & John Oates” vinyl greatest hits album enticing them to participate in the sponsorship tour. The LP was “Rock ‘n Soul Part 1”. The album cover featured Hall & Oates standing with a red 1984 Fiero SE.

Concurrent with the development of the production car was the development by Huffaker Engineering of a Fiero to compete in IMSA’s GTU road racing series. Clay Young was the team’s primary driver, with occasional guest appearances by John Oates.

The 1984 model line included a limited “Indy Pace Car” edition, consisting of an Indianapolis 500-themed option package on SE-model vehicles (a package that was specially reissued in 1985). 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 four-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 three actual Indy Pace Car Fieros that appeared at the 1984 Indianapolis 500. This inlet scoop, and the 2.7 L (160 cu in) Super Duty engine that they fed, were not available on the production model pace car replicas. The Super Duty engine produced 232 bhp (173 kW) at 6500 rpm and 210 lb·ft (280 N·m) of torque at 5500 rpm. Hoglund named Pontiac engineer John Callies to drive the actual pace car at Indy. Callies was the factory’s lead engineer on both the pace car and IMSA programs. Fiero became the first 4-cylinder car to pace the 500 since a Stutz paced the 1912 race, at a then record 144 mph (232 km/h).

The production of the 1984 model ran from July 1983 until almost the end of 1984, this resulted in Pontiac exceeding its first year goal of 80,000 units, which was 28,000 more 2-seaters anyone had sold before in the US, by about 56,000 cars.

1984 production
VIN Style Cars produced
1G2AE37RxEPxxxxxx Fiero 7,099
1G2AM37RXEPxxxxxx Fiero 2M4 62,070
1G2AF37RxEPxxxxxx Fiero SE 65,671
1G2AF37RxEPxxxxxx Fiero Indy 2,000
Total production 136,840


1985 Pontiac Fiero GT (rear)

The 1985 Fiero didn’t hit the showrooms until January 1985, with the introduction of the GT model, which looked just like the 1984 Indy model without the decals or body color wheels. The three models, and four colors, from the previous year were still available, but the problem with insufficient power was addressed, much to the satisfaction of the general public. A 2.8 L (170 cu in) V6 engine rated at 140 hp (100 kW) and 170 lb·ft (230 N·m) 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 four-cylinder engine was slightly modified, adding roller lifters and about 2 hp (1.5 kW), could now be paired with the Japanese-designed Isuzu five-speed transmission, used in the J-body platform, 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 Fiero Coupe

The 1986 Fiero arrived on 12 September 1986, however, the GT model was not listed. The previous years GT became the 1986 SE. The 1986 GT was delayed until 3 January 1986. This was the first time the fastback roofline was offered, sometimes referred to as a “1986½” model, as the new fastback body restyle was not yet ready for release at the start of the model year. 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 thus an image they did not want to promote. Individuals present at the unveiling of the new fastback roof style, in February 1984, at GM’s Arizona test track, actually thought it was a new Corvette at first. The Muncie/Getrag 5-speed transaxle, which did not arrive until June 1986, became the standard transaxle in V6 models. Models equipped with the four-cylinder engine remained largely unchanged. Red and Light Gray Metallic were dropped as colors with Light Gold Metallic (M56), Silver Metallic (M16) and Bright Red (M81) being added. 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)
1G2PG119#GP2##### Fiero GT 17,891
Total production 83,974


1987 saw changes to the front and rear fascias on the “base coupe” with the SE and GT models keeping the same “Aero” nose. The new non-aero noses lost the black bumper pads of the earlier models and had a smoother look. The four-cylinder engine’s power rating increased to 98 hp (73 kW) with some major modifications which included a roller cam, redesigned intake manifold, distributorless ignition system (DIS), 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 four-cylinder. Bright Blue (M21) and Medium Red Metallic (M77) were added and replacing the ribbed black molding was the round style found on the GT models. As a side note, the SE models retained the ribbed molding, 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 Pininfarina Ferrari 308-type body, called the Fiero Mera. Corporate Concepts completed the “Mera” transformation and none were sold as kit form. The Mera body change was offered only on new Fieros, sold through Pontiac dealers and is considered a class of car in its own right. Only 247 Mera’s were produced by Corporate Concepts before production was halted when sued by Ferrari. With its limited number produced, the Pontiac Mera is one of the rarest American made automobiles.

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 15,880
1G2PG119#HP2##### Fiero Mera 88
Total production 46,581


1988 Fiero Formula

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, along with what they learned from the racing program. Up front were revised control arms and knuckles that reduced steering effort and improved the scrub radius. In the back, the old Citation parts were replaced with a real tri-link suspension with all new knuckles. This new suspension came with staggered wheel sizes on WS6 suspension equipped models, with 15 in (380 mm) by 6 in (150 mm) wide wheels up front and 15 in (380 mm) by 7 in (180 mm) wide wheels in the rear for improved handling balance and to offset the slightly increased front track that resulted from the improvements. Topping off the package were the new vented disc brakes at all four corners, which addressed braking complaints of road testers. A variable effort electro-hydraulic power steering unit, the same design later found on the GM EV1, was also to be a late addition. This option never made it to production — one reason cited is that models with the prototype power steering were noted as being too loud. The four-cylinder engine received an in-pan oil filter element and balance shaft. A “Formula” option was added, which offered many of the GT features with the standard coupe body, including the 120 mph (190 km/h) speedometer, WS6 Suspension (which includes offset crosslace wheels) and the rear spoiler. 1988 marked the end of production for the Fiero, and 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. 1988 was also the only year a yellow exterior color was available as a factory option. During the Fiero’s final model year (on August 16, 1988) the last window sticker was placed on the last Fiero to roll off the Pontiac, Michigan plant line. The 1988 Fiero is the most desired by automotive collectors because of the improvements made to the 1988 model year, and this being the last year of production. The 1988 Mera seen as the most sought after model and tops the Fiero list in resale value this model is commonly used to create “kit cars” (replicas of high end sports cars).

1988 production
VIN Type Cars produced
1G2PE11R#JP2##### Fiero 13,910
1G2PE119#JP2##### Fiero Formula 5,484
1G2PG119#JP2##### Fiero GT 6,848
1G2PE119#JP2##### Fiero Mera 159
Total production 26,402

1990 (prototype)

1989/1990 Fiero Prototype, displayed at the 2006 Michigan Fiero Club show, “Fieros at the Hall”.

1989/1990 Fiero Prototype, Engine Bay.

1989/1990 Fiero Prototype, Interior.

A prototype of the never-produced 1990 Fiero was displayed at the 20th Anniversary show in July 2003, at Fierorama 2005, at the Michigan show in 2006 and most recently at the 25th Anniversary Show in Pontiac, Michigan in 2008. Continued showing of the prototype may no longer be an option in the near future, as GM has taken to cutting funding to relieve the pressure of its financial woes. GM Heritage Center continues storing the 1989/1990 Fiero. Many of the 89/90 coupe prototypes have been demolished in a scrap yard in Australia.

Much of its design influence is apparent in the Fourth Generation Firebird. New engines were proposed for the 1990 model year, from the then new DOHC 190 bhp (140 kW) “Quad 4” four-cylinder as a base engine to replace the 2.5L “Iron Duke” to a new 200+ hp DOHC V-6 for the GT models. Even a 231 CID (3.8 L) Buick Turbo V6 powered Fiero is rumored to have been seen at a test track. The single 1990 Fiero GT prototype had an early version of the upcoming DOHC V-6 that would be put into production in the Grand Prix and Lumina Z34 in the early 1990s. This engine developed more than 200 hp (150 kW).

GM cited slumping and unprofitable sales of the Fiero as the reason for its demise following its 5th model year.

Suspension design84-87 front suspension is a wider direct derivative of the Chevrolet Chevette and Pontiac T1000. It employs a double A-arm (or double wishbone) design common prior to the advent of struts, and has naturally good geometry. A drawback of this design, however, means that the car’s front suspension has four ball joints. Nevertheless, the tie-rods allow toe-in/out adjustability. Minimal camber adjustments exist on 1984 to 1987 models without an after-market upgrade that replaces the upper ball joints with slotted mounting points units. The joints have typical grease fittings for regular lubrication commonly found on pre-2000 autos.The rear suspension is essentially a GM X-car’s (Chevrolet Citation, Oldsmobile Omega and Pontiac Phoenix) front suspension moved to the rear of the Fiero. The uppers are top-plates and Chapman 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 four-wheel independent suspension provides uncharacteristically accurate handling for a vehicle of its size and price range. However, due to the use of multiple suspension pivot and attachment points (similar to the Corvette’s suspension architecture), maintaining the suspension is more costly than some less technical suspension systems.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 in 1988. The rear suspension featured multi-link (two lateral links and one trailing arm) Chapman strut suspension, and the tie-rod related bump steer experienced with the earlier suspension design was fixed. The brakes were also upgraded to 10.5 in (26.7 cm) vented rotors on the front and rear with an improved slide caliper design having larger diameter slides. The Fiero Formula (new for 1988) and Fiero GT models also received a rear anti-sway bar to compliment non-progressive rate springs.The 1984–1987 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 Chapman strut unit. Thus yielding a larger, 1984–1987 engine compartment with the ride-quality benefits of the 1988 suspension.In the August 1985 issue of Road & Track, the Fiero was tested against six 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: 57.2TransmissionsAutomatics

The Fiero’s mid-mounted 2.8 L V6

The Fiero’s mid-mounted base 2.5 L 4-cylinder

All automatic-equipped Fieros were equipped with the three-speed Turbo-Hydramatic 125 with torque converter lockup. Automatic transmission final drive ratios:

    • 1984–1986: 3.18 (RPO “F75”)
    • 1987–1988: 3.33 (RPO “GX3”)
  • THM-125 Gear Ratios
    • 1st Gear: 2.84
    • 2nd Gear: 1.60
    • 3rd Gear: 1.00
    • Reverse: 2.07

Four-speed manualAll four-speed manual transmissions were built at the Muncie, Indiana Allison plant. The 1984 production line saw two transmissions, a performance four-speed with a final drive ratio of 4.10, and an economy four-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 four-speed with a final drive ratio of 3.65. The lower-geared 4.10 four-speed transmission showed improved acceleration, but sacrificed fuel economy.Five-speed manualIsuzu and Muncie (Getrag)- five-speed transmissions were available, depending on model and equipment beginning in 1985 for the Isuzu five-speed which came on four-cylinder cars and in 1986 for the Muncie five-speed which came on V6 equipped cars. The Getrag 282 five-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 V6.Manual transmission gear ratiosCrash SafetyThe Pontiac Fiero, being popularly known as being “made entirely of fiberglass,” is wrongly accused of being unsafe in a collision.The Fiero, with its unique plastic body-on-spaceframe design, helped the Fiero achieve a NHTSA NCAP frontal crash test rating of five stars, the highest rating available.According to Hemmings Motor News, the exceedingly sturdy, 600 lb (270 kg) space frame consisted of roughly 280 separate galvanized and high-strength steel stampings joined by 3,800 welds and, when assembled with the Fiero’s mechanicals, was fully driveable without its skin. The Fiero’s body panels are purely cosmetic and carry no structural load. The Fiero was the second safest vehicle sold in America from 1984 to 1988, bested by the Volvo 740DL station wagon.The official crash test scores were as follows:

  • Head Injury Criterion – 356.5/308.6
  • Chest Deceleration (G)-30.9/29.9
  • Femur Load (LB)- Left 840/800 Right 800/740

The Fiero’s technologically advanced spaceframe technology went on to be incorporated in the Saturn S-series, Pontiac Transport and Chevrolet Lumina APV carlines.Problems and issuesEngine fire reputationOf the total production of the Pontiac Fiero of 370,168, 135 (.036%) of them were reported to have had engine fires, 122 of these occurred while driving, according to the NHTSA.The engine fires almost exclusively pertained to the 1984 model year. Later model years were produced with upgraded equipment, and frequency of engine fire was significantly reduced.
According to AutoWeeks publication of Fiero firing squad, on October 6, 1983 a Pontiac engineer wrote an urgent memo to report that two Fieros had suddenly caught fire during test drives. This was only 3 months after the production of the Fiero began at the Pontiac plant. It was thought to be caused by antifreeze leaking out of badly installed hoses but in reality it was defective connecting rods. After one meeting with the Saginaw foundry manager, he wrote that “…60 percent to 90 percent of the rods produced do not exhibit defects.” This means at least every 1 out of 10 rods produced were defective and possibly 4 out of 10 were also defective. The Associated Press quoted the National Highway Traffic Safety Administration as saying it had “…received 148 complaints regarding Pontiac Fieros catching fire including reports of six injuries…. Low levels of engine oil may cause a connecting rod to break, allowing oil to escape and come into contact with engine parts. The oil would catch fire when it contacted the exhaust manifold or hot exhaust components…. David Hudgens, a GM spokesman in Detroit… said, ‘If you ran out of oil, and then that coupled with some aggressive driving, perhaps, and maybe not changing the oil very often, you end up with a broken rod, and that’s where the connecting rod came in; it is still the owner’s responsibility to check the oil.’ “The Pontiac division claimed in a 1988 press release that “GM tests have shown that running these 1984 cars with low engine oil level can cause connecting rod failure which may lead to an engine compartment fire…. Pontiac is aware of 260 fires attributable to the condition, along with ten reported minor injuries.”The larger of the two reported numbers of cars with fires (260) amounts to 0.07% of Fiero models produced. The fires affected the 2.5 L engine almost exclusively, and mostly 1984 models (although there may have been additional occurrences after the above reports were published).There are several possible contributors to Fiero engines catching fire. The primary cause is thought to be a batch of poorly cast connecting rods, produced in GM’s Saginaw plant, which failed when the oil level became too low. One theory is that the sports car styling attracted buyers who would drive the car hard, most notably by excessively revving the engine. Another factor was the incorrectly listed three-quart oil capacity; the actual oil capacity is 4.5 quarts, but a misprint on the dipstick and in the owner’s manual resulted in owners using only three quarts, any leakage or consumption would allow the oil level to decline over time to a dangerously low level. If the proper oil level was not maintained, the bearings could seize, snapping the porous castings of the connecting rods. This could result in a hole being punched in the engine block, allowing oil to spray onto hot exhaust components where it could ignite.Alternatively, some fires may have been because of the engine wiring harness bulkhead connector (C500) being located in the center of the engine bay above the exhaust manifold, where heat could possibly melt and ignite the wiring. The 1984 model had a magnesium grille over this area. In later models, the main engine harness connector (C500) was moved to the battery area, and was improved to some degree with better heat shielding wrapped around the wiring harness.A third cause might be cracks in the engine block from overtightening the head bolts. Some engines developed cracks in the block that would leak coolant and/or oil, sometimes accompanied by broken head bolts directly above the crack. The leak would spray coolant or oil, the latter resulting in fire if sprayed onto the hot catalytic converter or exhaust manifold at the front of the engine compartment.Most vehicles existing today have been serviced by GM during one of the safety recalls on the car. For the fire-related recall, 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 clue that the car has been retrofitted. The addition of the longer AC Delco PF51 oil filter and a re-calibrated dipstick added extra oil capacity to the oiling system, and enabled running four quarts of oil in the crankcase instead of three, to help prevent oil starvation to the rods. Certain vehicles also had their connecting rods or entire block replaced.Any fires that happen today would most likely not be caused by the aforementioned causes, but instead due to faulty repairs and failure of engine components, wiring, etc. due to age.
Cooling system issuesWith a normal operating temperature of 220 °F (104 °C) prior to the recall switching to a 195 °F (91 °C) thermostat, the midmounted engine utilized long pipes to carry coolant to the front-mounted radiator. This demanded that a special coolant filling procedure be followed to prevent air pockets, as with many modern cars. Simply pouring coolant into the thermostat housing (on the engine) might leave an air bubble in the radiator, while adding coolant just to the radiator might leave an air bubble in the engine’s coolant passages. Proper procedure (with engine idling and the thermostat removed, filling the thermostat housing, popping the bubble out of the radiator by cracking open the radiator cap until coolant exits) must be followed in order to ensure an air-free cooling system.Another problem has become common since more Fieros are being serviced by auto repair shops which do not know their design very well. The underbody coolant tubes are positioned in a manner in which not even a casual glance underneath the car would suggest their vulnerability. As a result, many of them have been crushed by shop lifts, resulting in a near complete lack of engine cooling. The age of the car suggests that even General Motors dealerships may now be unaware of the proper jacking methods.However, the cooling system of the Fiero, properly maintained and in good working order, is more than adequate for even the most demanding environmental conditions.

Source: Wikipedia

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