How to Install a 7.3L Injector

Cut away diagram of a fairly basic fuel inject...

Cut away diagram of a fairly basic fuel injector for the fuel injection article (Photo credit: Wikipedia)

If you’re looking to replace or convert the engine in your current truck, be prepared to spend most of a day doing it. You have to take apart the top of the engine to get to the fuel injectors, so make sure you have the right tools for the job as well.

  1. You will need a socket wrench, shop towels, torque wrench, and a rotunda injector sleeve brush 104-00934-A. Oil drain pans are preferable, but as long as you have something to drain oil into, that’s good enough. Certain copper washers, nuts and bolts will also be needed, but you will have to check on the size as you go along.
  2. Open all the drain plugs and completely drain the oil. Put the drain plugs back in. The socket wrench will help you accomplish this task.
  3. Remove the valve cover and detach the electrical wiring.
  4. Remove the fuel/oil rail drain plugs.
  5. Remove the oil deflector. A retaining screw might be holding it in place, so you will have to take that out before you can completely take out the oil deflector.
  6. Take out the bolt holding the fuel injector in place.
  7. Remove the fuel injector from the fuel bore.
  8. Use the rotunda brush and shop towels to thoroughly clean the bore.
  9. Lubricate the new injectors with fresh oil and push into the bore until they’re properly seated in the O-rings.
  10. The injector replacer goes on next, followed by the retaining plate.
  11. Place the oil deflector on after that and tighten to 108 pounds with the torque wrench.
  12. Reconnect the wiring and appropriately tighten all drainage plugs to the suggested weight.
  13. The valve cover goes on last. Be sure to refill all the oil or your hard work will go up in smoke!

That’s it. Piece of cake, right?


ICM Explained

An Injector Control Module (ICM) is a device that provides the proper voltage to the fuel injectors in the 6.0 Ford Powerstoke Diesel. This voltage is crucial to the performance of the fuel injectors, and thus, the engine itself. The part may interchangeably be called a Fuel Injection Control Module (FICM).
It should be noted that the 7.3 Ford Powerstroke Diesel utilizes an injector drive module (IDM).

A minimum of 48 volts is required to operate the engine properly. Voltage of lower than 48 volts will result in a variety of operating problems. These problems can be challenging to find if you don’t recognize the potential problem as being the ICM and low voltage. Keep in mind the engine may still run at lower than 48 volts, but its drive-ability will be affected. Eventually, if voltage is reduced too low, the engine will fail to run.

Check the output voltage on the ICM by removing the bolts on the cover. Once the cover is off, use the screw under the cover as the positive. If the voltage does not read 48 volts (or very close to it) it should be replaced. Many replacement ICM’s offer slightly higher voltage than the 48v required for proper operation. These ICM’s may provide better fuel mileage along with an improved throttle response.

When checking the ICM it is also a good opportunity to check for corrosion in and around the ICM, its connections and at the wiring harness. To check the condition of the harness, tug on it slightly while the engine in operating. If you notice a change in the engine’s operation when you tug, it is likely there is a problem with the harness. The only fix for a bad harness is replacement.

High Pressure Oil Pumps in Powerstroke Engines

Diesel engine, Nippon Maru

Diesel engine, Nippon Maru (Photo credit: Joel Abroad)

In today’s internal combustion automobile engines, a multitude of moving parts translates into a dire need for an adequate lubricant. Engine oil fits the bill by lubricating parts such as bearings and by removing excess engine heat. In some engines, such as the Ford Powerstroke line of diesel truck engines, the oil pump fulfills other needs as well. However, if the oil pressure falls too low, then engine components may be seriously damaged. To ensure that the engine oil remains above a safe minimum pressure level, an oil pump circulates the oil within set limits.

In the Ford Powerstroke line of diesel engines, the high pressure oil pump doubles as the injection pump by sending high-pressure oil to the engine’s hydraulic electric unit injectors. The Ford 6.0 and 7.3 Powerstroke engines rely on an IPR valve and ICP sensor to measure and maintain adequate oil pressure, which varies according to the fuel injectors’ demands. This requirement, in turn, depends on the power needs derived from the driver’s demands. For instance, the fuel injectors require different oil pressures during idling, accelerating and holding a constant driving speed.

During normal operation, the Powerstroke oil pump sends the appropriate amount of oil to create the proper pressure in the engine–and especially the fuel injectors–according to factors such as engine temperature and resistance to flow from engine components. If the pressure becomes too high, then the engine must work unusually hard, leading to excess wear and tear; in addition, overly high oil pressure could even introduce air into the system. On the other hand, if the pressure becomes too low, perhaps due to engine wear or debris within the oil, then the result may be too much smoke and not enough power. In extreme cases, metal-on-metal contact without sufficient lubrication can physically destroy parts; just seconds of operating without oil can wreck an engine beyond repair.

Fuel Injection 101: How Fuel Injection Works in Diesel Engines

4-Stroke-Engine 1

4-Stroke-Engine 1 (Photo credit: Wikipedia)

Internal combustion engines, known as carburetors, used to run on blended fuel and air during the 80’s and 90’s. They have been replaced, though, by the fuel injection system that pumps fuel under high pressure so as to run into internal combustion engines.

Diesel engines initiate ignition, thus burn the fuel by utilizing the injected compression’s heat into the combustion chamber, while both gas and petrol engines use a spark plug so as to ignite the pre-mentioned mixture of fuel and air. The high compression ratio of diesel engines is held responsible for their exceeding thermal efficiency, when compared to either external or internal combustion.

Once air enters the diesel engine’s combustion chamber, it is compressed in high compression ratio the size of 15:1-22:1, releases pressure the size of 40 bars (while petrol engines produce up to 14bars) and heats the air to 1,022oF in a pre-chamber or a piston. At the highest level of the compression stroke, inside the combustion chamber, the compressed air gets injected by fuel. Then, the fuel is broken down to small drops that get evenly distributed, via a fuel injector. Those small drops get their surfaces vaporized by the compressed heat and start a series of vaporization and ignition until they are completely burnt in the combustion chamber.

The typical diesel sound that feels like a knock is due to the delay of the beginning of the vaporization process during ignition, which happens as vapors reach the temperatures of the ignition and result to pressure increase above the piston, which is then driven in a downward position to supply the ABS system with power.

When compression is made in high levels, combustion happens and there is no need to be separate ignition system. Similarly, the engine’s efficiency is increased due to upper levels of compression ratio.

Compression ratios are high because pre-ignition is prevented, as air and fuel are not compressed in diesel engines, since only air is compressed and fuel enters the cylinder just before TDC.

High levels of fuel pressure are reached due to mechanical pumps and then non-compressed air injectors, which are activated when pressure is applied on them, deliver the fuel to the combustion chamber. The rate that fuel is delivered is controlled by electronic or mechanical governors.

One can find either a 4-stroke or 2-stroke version of a diesel engine. However, modifying an EFI engine can be done by taking the duty-cycle and injectors’ pulse duration (controlled by the ECU) into close consideration.

EGR Coolers Optimize Powerstroke Performance

MTU Exhaust Gas Recirculation

MTU Exhaust Gas Recirculation (Photo credit: Tognum: MTU & MTU Onsite Energy)

The average Powerstroke engine features a number of innovative components that not only allow it to deliver exceptional performance, but also helps it to remain compliant with state and federal emissions requirements. An EGR cooler is just one of the many components that contribute to this engine’s excellent performance. To get an idea of how EGR coolers optimize Powerstroke performance, it’s important to know how the EGR system and EGR coolers work.

EGR valves are commonly used to help reduce engine emissions, especially nitrous oxide (NOx) gas emissions. These valves reintroduce a small amount of exhaust gases into the intake manifold. This action helps reduce peak combustion temperatures by diluting the air/fuel mixture by a small degree. Reducing peak combustion temperatures also has the effect of preventing the formation of NOx gases. EGR valves are a necessity on current diesel-powered vehicles, given the stringent emissions standards they are required to follow.

An EGR cooler further promotes the efficient operation of the EGR valve by reducing exhaust gas temperatures with the help of a heat exchanger. In the majority of cases, the engine’s own coolant is used to carry away heat passed on from the exhaust gases to the heat exchanger. The cooled exhaust gas is then recirculated into the intake manifold where it is introduced into the air/fuel mixture.

EGR coolers come in a variety of forms. However, the shell and tube design is one of the most common thanks to its relative simplicity and overall durability. In this design, hot exhaust gases pass through the middle of a series of long tubes running the length of the heat exchanger. Meanwhile, engine coolant flows around the outside of the tubes, carrying away heat from the exhaust gases. There are other designs available that take advantage of unique design and materials challenges.

For the Powerstroke, the EGR cooler optimizes the engine’s performance by lowering the operating temperature of the combustion chamber to manageable levels, preventing internal damage caused by detonation. It also helps lower NOx emissions, keeping the engine in compliance with emissions standards.

How important is pressure in Power Stroke?

English: Efficiencies of two stroke diesel eng...

English: Efficiencies of two stroke diesel engine. η m : mechanical efficiency η i : thermal efficiency η t : total efficiency b e : specific fuel consumption (Photo credit: Wikipedia)

High pressure oil pumps are important in terms of reliability and efficiency of a Power Stroke engine. Increasing the fuel consumption in a Power Stroke engine means more lubrication is necessary to keep it running smoothly.All engines require adequate amounts of oil to be pumped over and around its moving parts (pistons, rings, tensioners, etc.) to prevent the friction between them from creating too much heat. When engines over heat, gaskets and seals breakdown causing leaks which leads to other serious repair problems.

A Power Stroke engine is capable of producing massive amounts of power. To help the engine achieve the extra power, a high pressure oil pump is needed to keep the engine cool and all the internal parts moving freely. The additional lubrication helps moving parts slide smoothly against adjacent surfaces and allows the engine to increase its performance. The improved efficiency increases the miles per gallon as well as reduces stress on engine components.

Synthetic lubricants can be used instead of regular petroleum based oil in high pressure oil pumps and still retain maximum efficiency. In fact, synthetic lubricants do not breakdown or lose their viscosity as quickly as oil or petroleum products. Changing oil as often as stated within the truck manual suggests will increase the life of the oil pump as well as that of the engine. The rule of thumb is every 3 months or every 3,000 miles depending on the type and purpose of the vehicle.

With the added benefits of a high pressure oil pump, the Power Stroke engine is capable of pushing larger volumes of diesel through the chambers, increasing both speed and overall power. The importance of pressure in both the fuel system and the lubrication system is apparent if you plan to keep your engine running smoothly and efficiently for long periods of time.



English: Line art drawing of a diesel engine.

English: Line art drawing of a diesel engine. (Photo credit: Wikipedia)

The 6.0-liter Power Stroke diesel engine replaced the 7.3-liter Power Stroke in the middle of the 2003 model year. As with its predecessor, the engine relies on an injector control module.

Unlike gasoline engines, diesel engines rely on heat from compression to ignite the air fuel mixture. This high compression requires equally high injection pressures.

Older Ford diesels used a hydraulic injection system. Through that system, fuel pressurized, causing the injection pump to trigger the injector. The problem with the hydraulic injection system was that air entering the fuel lines would often disable the injectors, or hamper their operation significantly.

The 6.0-liter Power Stroke operates with fuel being supplied to the injectors through fuel rails inside the cylinder heads, as well as high pressure engine oil. A computer determines when a cylinder should fire, and then signals the Injector Driver Module, which sends a pulse-width modulated signal to the injector solenoid. The solenoid then opens a poppet valve, thereby allowing high pressure oil to flow into the intensifier piston. The piston is forced down, which pressurizes fuel inside the injector. When fuel pressure in the injector reaches roughly 2,700 psi, the injector pintle rises and fuel is injected into the cylinder.

The engine’s injector control module voltage output is 48 volts. You can check the output by removing the two access cover bolts and using the screw under the cover as a positive. If the voltage reads well below 48, it should be replaced. Even though the engine will run with voltage as low as 30 volts, it will not run properly.