Power Stroke FAQ

Frequently Asked Questions about the Power Stroke Diesel

Who Makes the Power Stroke?

The "Power Stroke" trademark first surfaced with the introduction of the 7.3L Power Stroke, an adaptation of International's model T444E, during the 1994 model year. International Navistar would go on to develop and manufacturer the 6.0L and 6.4L Power Stroke diesels before Ford and International parted ways. The 6.7L Power Stroke was developed and is produced strictly by Ford Motor Company.

What engine did Ford use before the Power Stroke?

Ford's first diesel engine was the International 6.9L IDI, released for the 1983 model year. This engine design would later be revised and released as the 7.3L IDI for the 1988 model year. The 7.3L IDI is not to be confused with the 7.3L DIT Power Stroke.

What is the Difference between the 7.3 IDI and DIT?

The 7.3L IDI and 7.3L DIT are two completely different engines, though both were developed and manufactured by International. The 7.3L IDI is an indirect-injection, mechanically operated engine that was primarily built naturally aspirated. The 7.3L DIT is another name for the 7.3L Power Stroke. DIT stands for direct injection, turbocharged. The later DIT engine uses a HEUI injection system and is electronically controlled. While the engines are dimensionally similar, they operate under two very different technologies.

Does Ford own Cummins?

Absolutely not - Ford does not and has never owned Cummins, nor a majority stake in the company. They did invest in the company in the early 90's, acquiring just under 11% of the company's common stock, which was sold back to Cummins in 1997. Ford has previously offered Cummins engines in their medium duty truck line, which could be where the rumor started.

Why happen between Ford and International Navistar?

Without getting into the nitty gritty details, multiple lawsuits were exchanged with regards to who would pay for the outstanding list of warranty claims from the 6.0L Power Stroke. International Navistar went on to provide the 6.4L Power Stroke, but Ford decided that it was more strategic for them to develop their own engine. In addition to engineering an engine specific to their own needs, Ford has been able to streamline the warranty process. Both the product and customer service seem have been greatly improved since the introduction of their in-house 6.7L Power Stroke.

What is a VGT?

VGT stands for variable geometry turbocharger. A VGT is a single turbocharger that displays the characteristics of both a small and large turbo by altering the A/F of the turbine. This is done by a series of mechanical vanes which open and close to increase or decrease the concentration of energy acting on the turbine wheel.

What is a DOC?

A DOC, or diesel oxidation catalyst, is an emissions control device that converts carbon monoxide and hydrocarbons into water vapor and carbon dioxide through an oxidation reaction. The DOC is typically mounted at the outlet of the turbocharger downpipe and, in complex aftertreatment systems, typically processes exhaust gases upstream of additional equipment. A DOC is the diesel equivalent of a catalytic converter.

What is EGR?

Exhaust gas recirculation (EGR) is the process by which spent exhaust gases are cooled and recirculated through the intake of the engine. The EGR process helps to lower the emission of nitrous oxides (NOx), compounds that both contribute to the development of lower atmospheric smog and induce respiratory problems. Ever seen a smog induced "blackout" in China? NOx emissions are partially to blame.

What is a DPF?

A diesel particulate filter or DPF is a device used to filter particulate matter from the exhaust stream of a diesel engine. Modern DPFs are highly efficient and capture anywhere between 85% and 100% of soot produced by the combustion of diesel fuel. Since the development of soot is difficult, maybe even impossible to prevent, aftertreatment is necessary to reduce the emissions of these harmful particles. As the DPF reaches max capacity, it enters a cleaning process known as regeneration, regen, or reburn. During the regen process, exhaust gas temperatures are increased and particles accumulated in the filter are burned off.

What is SCR?

Selective catalytic reduction (SCR) is an emissions control process by which NOx emissions are considerably reduced. An SCR system relies on the injection of a urea based exhaust fluid (DEF), which mixes with exhaust gases before entering a catalyst. In the catalyst, a reduction reaction occurs converting nitrous oxides into water vapor and nitrogen gas.

What is DEF?

DEF is a solution of urea (~32%) and distilled water, in addition to additives that promote a longer shelf life. The purpose of DEF is to facilitate the reduction of NOx emissions in the SCR system. DEF is highly corrosive, so great care should be taken in storage and filling of the DEF tank. The use of DEF is mandatory on the 6.7L Power Stroke - failure to maintain the fluid level will result in penalties that include speed limiting and de-rating of engine power.

Can I shut my truck off during regeneration/regen?

This is a difficult question to answer and often sparks controversy. Can you shut your truck off during regen? Sure, you can indeed shut your truck off during regen. Should you should your truck off during regen? Occasionally shutting the engine down during a regeneration cycle is not likely to cause immediate problems. However, it is preferred that owners of DPF equipped trucks not make a habit of interfering with active regeneration cycles. If a regen is occurring at an inconvenient time, it is good practice to allow the engine to idle a few minutes first. In theory, the engine will read a high backpressure condition and re-initiate the regen at later time. One of the problems with shutting down during a regen is that the turbocharger is extremely hot and ideally needs time to cool before the engine is shut down. After the engine is shut down, oil no longer circulates through the turbocharger and risks cooking in the bearing channels.