Midway through the '94 model year, Ford began equipping trucks with a revolutionary new diesel engine built by International. The market-changing V-8 displaced 444 ci (7.3L), was direct-injected, turbocharged, and featured a hydraulically actuated, electronically controlled unit injector (HEUI) fuel system. The engine was designated the T444E by International, meaning the engine was a turbocharged 444ci mill that was electronically controlled. Ford called it the Power Stroke. With the release of the 7.3L Power Stroke, International pioneered the idea of electronically controlled diesel engines in pickups, which would later become commonplace on GM and Cummins diesels.
In 1994, Power Strokes effectively revolutionized the diesel market in terms of power with 210 hp and 425 lb-ft of torque, as opposed to the previous IDI turbo numbers of 190/390. To further put the mid-'90s turbodiesel scene into perspective, the '94 Cummins put out 175 hp and 420 lb-ft and the GM 6.5L put out 180 hp and 360 lb-ft.
While considered a modern...
While considered a modern marvel in its day, the first-generation Power Stroke's simple overhead two-valve design carried over from its predecessor, the 7.3L IDI.
Engine Basics
The first-generation Power Stroke's combination of a simple, overhead two-valve design coupled with conservative power ratings resulted in a reliable, efficient diesel engine that could last 300,000 miles and beyond. The engine utilized a bore of 4.11 inches, a stroke of 4.18 inches, a cast-iron block, cast-iron cylinder heads (six bolts per cylinder) and forged steel connecting rods. The compression ratio on the Power Stroke was lower than its predecessor at 17.5:1. Dry engine weight was a stout 983 pounds.
Second-Generation Power Stroke
The second generation of 7.3L began with the '99 model year. This version of the Power Stroke was intercooled (termed charge air cooling or CAC), fittingly for trucks labled "Super Duty," and put out more horsepower and torque. First-year Super Dutys and '00 engines put out 235 hp and 500 lb-ft of torque. Although '99 and '00 models shared the same engine, '99s can be spotted by their "Power Stroke V-8" badge that is visible in front of the truck's front fender-wells. Power Stroke badges built in 2000 or later are displayed on the bottom of each truck's door panels.
Hydraulically Actuated Electronically Controlled Unit Injector
The new HEUI fuel systems on the Power Stroke required the use of two oil pumps. A low-pressure (lubricating) pump feeds oil into the high-pressure oil reservoir, where the high-pressure oil pump (HPOP) forces oil through oil lines to two high-pressure oil rails, one located in each cylinder head at an injection oil pressure of 500-3,000 psi. The pressure is controlled electronically by a regulator located inside the pump. Basically, all of this culminates in a unique system where the oil increases the fuel pressure at the injectors.
All first-generation Power Strokes came equipped with 15-degree high-pressure oil pumps located at the front of the engine, a mechanical fuel pump in the engine's valley, and 90cc shot fuel injectors.
Ford introduced both their...
Ford introduced both their Super Duty truck lineup and an improved version of the Power Stroke in 1999.
Induction
A traditional journal-bearing turbocharger was used on all first-generation Power Strokes. The turbo also utilized a wastegate. Second-generation engines came equipped with a smaller turbine housing for quicker spool-up times. Air was drawn into the engine via an oval air filter located on the driver side behind one of the batteries.
Fuel System And Induction Changes
Subtle changes in the turbocharger and injection system led to a smoother idling, cooler running engine that increased horsepower to 235 at 2,700 rpm and torque to 500 lb-ft at 1,600 rpm for the '99-00 model years. A calibration change increased output to 275 hp and 525 lb-ft on the '01 models equipped with a manual transmission, while Power Strokes mated to the 4R100 automatics had a 250hp, 505-lb-ft rating.