What Does IDI Diesel Stand For?

From 1983 until 1994, the International Harvester IDI (Indirect Injection) engine was a four-stroke diesel V8 engine that powered International Harvester school buses, trucks, Ford F-Series pickups, and Ford E-Series vans. The engine was available in two sizes: 420 cubic inches (6.9 L) for Ford trucks from 1983 to 1987, and 444 cubic inches (7.3 L) for Ford trucks from 1988 to 1994 (naturally aspirated) and in 1993 and 1994. (turbocharged).

The IDI engine was superseded by the Navistar T444E engine in 1994, which shared just the displacement of the IDI.

The T444E was the first Ford Power Stroke engine to hit the market.

What is the difference between IDI and powerstroke?

The 7.3 IDI engine is different from the 7.3 Powerstroke engine. Despite the fact that they have the same displacement designations, these engines have a lot of variances. The 7.3 Powerstroke is computer-controlled, while the 7.3 IDI is completely mechanical. Previous post: Can You Travel Long Distances with a Classic Truck?

Is IDI or powerstroke better?

The IDI is easier to work on, more durable in the long run, and easier to run alternative fuels in. The powerstroke has several modifications that make it superior to the IDI.. and the hpop isn’t a big concern if you know how to look after it.

What does the IDI mean?

“I Doubt It” is the acronym for “I Doubt It.” IDI is a response to a statement or an inquiry regarding something that is incorrect or unlikely to happen.

What is a 7.3 L IDI?

From 1986 to 1994, the International 7.3L IDI (indirect injection) was a four-stroke V8 diesel engine series that was utilized in International Harvester school buses, commercial trucks, Ford F-Series trucks, and Ford Econoline/E-series vans.

In the early 1980s, Navistar (then International Harvester) teamed up with Ford to develop a low-cost, light-weight diesel engine as a replacement for V8 gasoline engines in Ford trucks and vans. The Navistar V8 diesel engine series, which predated the famed Power Stroke diesel engine series, helped Ford win the tough truck sales war against GM and Dodge diesel trucks.

This Navistar International 7.3 IDI diesel engine is part of our Diesel Engine Guide series to assist with the purchase of a used school bus.

Due to its popularity, nearly 2 million 7.3 Power Stoke engines were produced from International’s Indianapolis plant.

Ford coined the term “Powerstroke” to describe its diesel engine lineup. The 7.3-liter powerstroke is a Navistar T444E, manufactured by Navistar International (previously International Harvester). The 7.3 is used in school buses, transit buses, and other large commercial vehicles, in addition to Ford Super Duty trucks.

It has a 17.5:1 compression ratio.

The compression ratio is the difference between the volume of air in the cylinder when the piston is at the bottom of the stroke vs when it is at the top of the stroke. Higher compression ratios enable more power to be produced while lowering exhaust gas temperatures. The higher the compression, the hotter the air inside the cylinder is, requiring less fuel to ignite and produce combustion.

Because the 7.3 Powerstroke uses glow plugs rather than spark plugs, higher compression ratios are required to raise air temperatures sufficiently for ignition to occur. The 7.3’s compression ratio is comparable to that of the Duramax and Cummins engines of the period.

The 7.3 Liter Power Stroke has a dry weight of approximately 920 lb (420 kg).

This engine is the largest mass production diesel engine at 7.3 liters (not including commercial vehicles). It is also one of the largest production engines of its time, trailing only the Bugatti Veyron’s 8.0L 16-cylinder engine and the SRT Viper’s 8.4L V10 engine in terms of displacement.

Surprisingly, it weighs less than the Cummins 5.9L V6 12v of the time and its replacement, the 6.0 Powerstroke, at 920 pounds.

From the factory, the 7.3 Power Stroke engines produced up to 250 hp (190 kW) and 505 lb·ft (685 N·m) of torque in automatic-transmission trucks during the last years of production, and 275 hp (205 kW) and 525 lb·ft (712 N·m) of torque in manual-transmission trucks.

While these statistics may be poor by today’s diesel power standards, the powerstroke held its own against its competition. The 7.3 can easily add 100whp for less than $2,500 for customers desiring extra power.

In 1999, an air to air intercooler was added to cool the charged air from the turbo for increased air density.

Due to the inclusion of an intercooler and higher-flowing injectors, 7.3 powerstrokes from 1999 to 2003 had dramatically improved performance potential. Take a look at our list of the top 7.3 Powerstroke mods available.

The 7.3 Power Stoke utilizes a cast iron block and cast iron cylinder heads.

This monster is a hefty lump of iron at 7.3L. It’s partly due to the size of the engine block that your 7.3 takes a long time to start in cold weather. The glow plugs have to work extra hard to light up the 7.3 in cold weather since cast iron blocks have superior durability but poor heat transfer.

It utilizes a single turbocharger with a turbine housing size of 1.15 A/R.

From 1994.5 until 1997, the turbo used a fixed geometry Garrett TP38 with no wastegate. In 1999, the TP38 was improved to include a wastegate in addition to the intercooler. In 1999.5, the 7.3 turbo was modified once again to the Garrett GTP38 wastegated turbo.

The 7.3 Power Stroke is based on International’s T444E engine (the name “Power Stroke” is unique to Ford vehicles)

Ford’s diesel engines in its Super Duty vehicles are marketed under the name Powerstroke, or formally “Power Stroke.” The engines were made by International Harvester, which was renamed Navistar International after a restructuring in 1986. Navistar is currently owned by Volkswagen.

Following the dangerous 6.0 and 6.4 powerstroke engines, Ford severed their ties with Cummins and began producing the Power Stroke in-house, beginning with the 6.7.

Production of the 7.3 Liter Power Stroke engine ceased in 2003 in order to meet emission regulations.

Diesel engine variations had relatively limited life cycles during the 2000s. As emissions rules become increasingly stringent, diesel engines must continually innovate to become more environmentally friendly. Diesel emissions rules are the reason modern diesels have advanced systems like DPF, SCR, and DEF, among others.

The lack of emissions equipment is one of the reasons the 7.3’s are still so valued today. Diesel emissions systems have a reputation for being difficult and expensive to fix, prompting many owners to either remove the emissions systems or look for older diesel trucks.

Fuel for the 7.3 Power Stroke engine is provided by Direct injection, HEUI (hydraulic electronic unit injection) Injectors.

While the HEUI system is no longer in use in favor of more advanced injection systems, it was a technological marvel at the time. The HEUI technology allowed the 7.3’s injection system to pressurize diesel fuel at 7 times the pressure of the oil. Without going into technical details, there were various advantages to the HEUI system:

  • When compared to traditional camshaft control, electronic control provides more flexibility and control over injection events.
  • Injector pressure was increased to 21,000psi, compared to less than 5,000psi for Cummins and Duramax engines at the time.

When did the Ford 7.3 Get a turbo?

Although the first Powerstroke diesel engine didn’t appear until late 1994, the Powerstroke tale began in 1982 when Ford partnered with ITEC to produce diesel engines (International Truck and Engine Corporation). It was a 6.9-liter indirect injection (IDI) engine for the first one. Although it only had 170 horsepower and 315 pound-feet of torque, these were outstanding figures for the 1980s.

The 6.9-liter IDI engine was produced until 1987, when it was replaced by the 7.3-liter IDI engine. Between 1987 and 1993, this engine was produced with the same stroke as the preceding 6.9-liter but a larger bore. The cylinder heads were totally reworked, and the engine block was strengthened as well. There was no turbocharger on this engine. This 7.3L IDI engine was the forerunner of the 7.3-liter Powerstroke engine that we are all familiar with today.

The turbocharged 7.3L made its debut in 1993. Internal sections of the engine were also updated to resist the turbo boost pressure. This engine didn’t gain much of a power or torque boost despite the turbo. However, it didn’t matter in the end because Ford was ready to release the engine that would revolutionize the industry.

Introducing the First Powerstroke: The Legendary 7.3-liter

The first Powerstroke turbo-diesel was a direct-injection engine that was produced between 1994 and 2003. A wastegate turbocharger, HUEI fuel injectors, and an air-to-air intercooler were among the 7.3 Powerstroke items available at the time. This engine had the same displacement as the previous one, but it included an electronically controlled direct-injection system that allowed it to produce up to 21,000 psi.

The first model 7.3-liter Powerstroke was built to last, with a 4.11-inch bore, 4.18-inch stroke, cast-iron block and cylinder heads, and forged steel connecting rods. It routinely went to 300,000 miles and beyond. The air-to-air intercooler and HEUI fuel injectors were introduced in the second version of the 7.3-liter Powerstroke in 1999.

HEUI fuel injectors were a key component of the second-generation Powerstroke’s new parts. A low-pressure pump and a high-pressure pump were required for the new system. The low-pressure pump pumps oil into the high-pressure reservoir, which the high-pressure pump subsequently forces through oil lines into the high-pressure oil rails. The injection pressure varies between 500 and 3,000 psi, resulting in an increase in fuel pressure at the injectors due to the oil pumps.

This second series of 7.3-liter Powerstroke engines was produced until 2003 and is still regarded as one of the best diesel engines ever by many diesel enthusiasts. It frequently exceeded a quarter-million miles.

Meeting Emissions Requirements with The 6.0-liter Powerstroke

In 2003, ITEC, now Navistar, teamed up with Ford to produce the 6.0-liter Powerstroke engine. The decision to drop the venerable 7.3-liter was influenced by new government pollution standards. To compete with the GM Duramax and Cummins Turbo Diesel, the Powerstroke needed to provide higher power while emitting fewer pollutants.

The new 6.0L Powerstroke used a new variable geometry turbo and various new emissions control components to enhance power to 325 horsepower and 570 pound-feet of torque.

Unfortunately, some 6.0 Powerstroke equipment, such as the oil cooler, EGR cooler, high-pressure oil pump, and head gasket, were prone to failure. Despite the fact that several 6.0-liter Powerstroke engines are still in use today, the engine’s reputation for reliability caused Ford to discontinue it in 2007.

The Clean and Quiet 6.4-liter Powerstroke

In 2007, Navistar teamed up with Ford once more to produce the 6.4-liter Powerstroke. The HEUI technology was used in previous Powerstroke diesel parts, however this engine added a common rail system with piezoelectric injectors. The 6.4 received its boost from two consecutive turbochargers. This engine had a power output of 350 horsepower and a torque output of 650 pound-feet.

The 6.4 Powerstroke had other issues, while fulfilling the strict diesel emissions rules of the period. One of the most common criticisms was the engine’s low fuel efficiency for a diesel engine. It was, however, unquestionably quieter and more powerful than the previous engine.

It, like the 6.0, was only produced for a few years before the Navistar-Ford relationship ended in 2010.

The Powerful and Efficient 6.7-liter Powerstroke

Ford decided to build its own Powerstroke engine without the help of Navistar in 2011. This engine featured a new design that included a water-to-air intercooler and a DualBoost variable geometry turbo. The 6.7-liter Powerstroke benefited from cutting-edge diesel technology such as its Instant Start feature and a lightweight compacted graphite iron engine block, which made it 160 pounds lighter than the 6.4-liter Powerstroke. The 6.7 utilises a common-rail injection system, just as the previous engine.

Initially, this engine had 390 horsepower and 735 pound-feet of torque. Ford managed to push it to 400 horsepower with a new turbo just a year later. By 2015, Ford has increased the output of the new 6.7-liter engine to 440 horsepower and 860 pound-feet of torque. The max torque of the engine increased to 925 pound-feet in 2017, while the horsepower stayed same.


In comparison to the two engines that came before it, the 6.7-liter Powerstroke has shown to be quite reliable. The iconic 7.3-liter, on the other hand, is still revered by many diesel aficionados. If you don’t want to upgrade to Ford’s newest Powerstroke, there are plenty of 7.3 Powerstroke performance parts available to help you get the most out of this older engine.

ProSource has all the performance diesel parts you need for any Powerstroke engine, so you can get the most out of your truck.

How does IDI diesel work?

Indirect Injection is the abbreviation for Indirect Injection. For diesel engines, this technology is used to achieve faster engine speeds. It’s commonly found in light-duty diesel engines found in older passenger cars, sedans, and multi-utility vehicles. The injector with an indirect injection system does not spray the diesel directly onto the piston. Instead, the diesel is injected into an auxiliary chamber, often known as a ‘Pre-combustion chamber,’ inside the cylinder head.

In the pressurized air, the Pre-combustion chamber provides swirling action. This aids in the consistent mixing of diesel and air. The air in this system flows quickly while mixing the fuel and air. The air from the engine cylinder enters the pre-combustion chamber first during the compression stroke. As the temperature of the air rises as it is compressed, the air becomes hot. An injector is currently injecting fuel into the pre-combustion chamber. The fire starts in the pre-chamber and subsequently spreads throughout the cylinder.

What is a 7.3 Powerstroke?

The 7.3 L Power Stroke V8 is the Ford version of the Navistar T444E turbo-diesel V8 and is the first engine to receive the Power Stroke brand. The Power Stroke/T444E was introduced in 1994 as a replacement for the 7.3 L IDI V8, and it is an entirely new design with just its bore and stroke dimensions in common with its predecessor (resulting in a displacement of 444 cu in (7.3 L)). The Power Stroke was available in three-quarter-ton and bigger variants of the Ford F-Series and Econoline product ranges, just like the IDI diesel.

The 444 cu in. Power Stroke is an electronically controlled, direct injection engine with a bore and stroke of 4.11 in. x 4.18 in. (104.4 mm x 106.2 mm) with a displacement of 444 cu in (7.3 L). It has a compression ratio of 17.5:1 and a dry weight of 920 lb (417 kg). In automatic transmission trucks from the latter years of production, this engine produces up to 250 horsepower (186 kW) and 505 lbft (685 Nm) of torque, and 275 hp (205 kW) and 525 lbft (712 Nm) of torque in manual transmission trucks. The oil pan holds 15 US qt (14 L; 12 imp qt), plus an additional 3 US qt (2.8 L; 2.5 imp qt) in the top end (owing to the HPOP), for a total of 18 US qt (17 L; 15 imp qt) of oil in the engine.

The “single shot” HEUI (hydraulically actuated electronic unit injection) fuel injectors on the 1994.5 to 1996/97 DI Power Stroke were AA code injectors unless they were from California, in which case they were AB code injectors. It used a high-pressure oil pump (HPOP) to generate the required oil pressure for the fuel injectors to fire. The HPOP on this iteration of Power Stroke has a 15° swash plate angle. A two-stage cam-driven fuel pump is used in the 1995-1997 trucks, whereas an electric fuel pump is installed on the frame rail in the 1999-2003 trucks. Due to decreased fuel pressures with the deadhead design, the 1999-2003 trucks also have a deadhead fuel system with a “long lead” injector in cyl. 8. (AE code injector). Split-shot fuel injectors of 120 cc (7.3 cu in) were installed in California vehicles in 1996 and 1997; split-shot injectors were not installed in other trucks until 1999. Single-shot injectors only inject one charge of fuel per cycle, but split-shot injectors release a modest load before the main charge to provide for a more damped start to combustion. By providing a more complete burn, this “pre-injection” helps to lessen the sharp combustion “knock” as well as reducing NOx emissions.

The 94.5-97 engine has a single non-wastegated turbocharger with a turbine housing size of 1.15 A/R. An air-to-air intercooler was added in 1999 to cool the turbocharged air and enhance air density. The new cooler, denser air would boost the engine’s horsepower capability while simultaneously lowering exhaust gas temperatures (EGT). Halfway through the 1999 model year, the turbine housing was altered to a.84 A/R and a wastegate was added. Injectors were increased to 140 cc (8.5 cu in) in the 1999 engine, up from 120 cc (7.3 cu in) in the earlier generation. The HPOP capabilities was boosted with the larger injectors by using a 17° swash plate angle to satisfy the requirements of the new, higher flowing injectors.

The engine used forged connecting rods until early 2002 versions, when powdered metal rods were introduced.

Bore scopes can be used to confirm the changeover between the 01-02 year models and serial numbers. These new connecting rods were adequate in an unaltered engine, but they would become a potentially catastrophic failure point if the engine was tuned beyond 450 horsepower (336 kW). Early models did not employ any type of exhaust aftertreatment, such as a catalytic converter, because pollution regulations for diesel engines were not in place. However, by mid-2002, Ford had begun installing catalytic converters as part of the OEM exhaust as part of the Tier 1-3 criteria.

Can you turn up the fuel pump on a 7.3 Powerstroke?

There’s no need to turn up the fuel on a 7.3 injector pump if you like the longevity of the factory fuel settings on your 7.3L diesel engine. On the other hand, a significant section of the market enjoys improving performance. Increasing the fuel pressure adds 25 horsepower for no additional expense. What you may not realize about this engine is that it can be made to produce greater power without the need for additional equipment.