What is an Injector Control Module?

Certain series of Ford diesel trucks use a Power Stroke engine. For example, Econoline vans, F-Series pick-ups and the Excursion. An important component of the Power Stroke engine is the injector control module, also known as a fuel injector control module (FICM.) The FICM needs to be programmed with the vehicle’s specific data to work properly.

The purpose of the injector control module in a Power Stroke engine is to convert voltage. In a 6.0 liter diesel engine the FICM will convert 12 volts to 48 volts and in a 7.3 liter diesel engine it will convert 12 volts to 115 volts. Without the FICM, a vehicle won’t start. The injector control module works in conjunction with the vehicle’s power train control module signifying when to fire each of the fuel injectors. It is also responsible for managing how much fuel is sent to the engine.

Injector control modules are used only in diesel engines and are generally located on top of the valve cover. Due to the high heat and vibrations it experiences on account of its location on the valve cover, it is very common for the FICM to go bad. When the FICM fails, the vehicle may stall or not start at all.

What is an Injector Driver Module?

The collaborative efforts of Caterpillar and International introduced electronic fuel injection to the 7.3 Power Stroke. This engine relies on extremely high oil pressure to build fuel pressure within the fuel injector.

The 7.3 is a direct-injection fuel injection where the fuel is injected directly into the extreme pressures of the cylinder, thus the reason for the high fuel pressure to overcome these pressures.

The 7.3 Power Stroke uses a PCM (powertrain control module) in conjunction with the IDM (injector driver module) to operate the engine. The primary function of the IDM is to boost the DC (direct current) signal sufficiently to operate the fuel injector under such loads. The standard 12 volts would be insufficient in opening the pintle in the injector under these pressures, so the IDM increases the voltage to 115 volts.

The high voltage allows for much faster and accurate opening of the injector. Engine mods are available to further increase this voltage increasing the power and torque by 20 percent or better.

If the voltage drops through resistance in the harness or connector the vehicle will run, but poorly with a severe lack of power. In a failure of the IDM the engine will not start at all.

At this voltage the reaction time is significantly multiplied. The PCM, through various sensors detecting engine speed and load, controls the on and off time of the injectors. A grounding circuit does this for each injector within the computer. Essentially the computer supplies the ground that operates the injectors which has a constant supply of voltage with the key on.

The 6.0 Power stroke system is somewhat different in that it uses a PCM and a FICM (fuel injection control module) both of which are flash programmed. Under this system each injector is operated with the use of an open and a closed driver solenoid.

The PCM is the primary controller in the decision making as to the timing and length of injector pulse, while the FICM is in control of the injector drivers. Both the PCM and the FICM are intrinsically linked through the use of a “CAN.” When replacing either of the units it is necessary to flash them unless purchased from a location claiming to have already done so.

The IDM is located under the fenderwell on the passenger side of the truck. Should any driveability issues arise, access the IDM and check both the harness and the connector. They are prone to failure due to their location. Start the engine and wiggle the wires to the IDM while paying particular attention to engine speed. If the harness or connector is faulty, the engine will respond to the movement of the harness.

As a last word, to prevent problems down the road with a diesel engine, especially a Power Stroke-keep in mind that the injectors operate off oil pressure. The oil pump rests on the top rear of the engine behind the manifold and under the turbo.

It is prone to leaking which reduces the oil pressure and hence lowers the injector performance. A failed oil pump-which is common place-will cause a no start.

Always change the oil at the correct time (mileage) and with the proper grade only. Generally every 2000 miles is appropriate. Diesels will not go as far between oil changes due to engine blow by due to high compression leakage past the rings and valve guide and contaminating the oil. Once contaminated a whole bucket of worms is opened.

What is an Injector Control Module’s Function?

The injector control module, also known as the injector driver module, is a “stepping stone” between the powertrain control module and the fuel injectors. It is used to prevent a large amount of voltage going through the powertrain control module. The injectors take a lot of voltage — more than a 12-volt battery can put out. The IDM amplifies voltage so that the injectors have enough to fire quickly.

The powertrain control module sends a signal to the injector control module. In turn, the injector control module or injector driver module fires the injectors. This module uses voltage to fire the injectors. If the injector driver module fails, the engine may run poorly, but in most cases, won’t even start. In addition, if a fuel injector fails, it fails to buzz. The rest of the injectors will also fail to buzz to protect the injector driver module.

Injector driver modules may be modified for higher voltage output, faster injection pulsation and longer injector on-time. Because the powertrain control module does not see what the injector driver module is doing, it doesn’t set a code. A stock injector driver module turns the injectors to fully on in 560 millionths of a second. A modified injector driver module could turn the injectors fully on in 440 millionths of a second, depending on the modification.

If the injector driver module is bad and has been properly diagnosed, you can purchase one here and replace it yourself. Replacement steps depend on the year, make and model of your Ford Powerstroke.

Importance of Injector Control Module in Powerstroke Engines

Jeep 2.5 Liter, four-cylinder engine, chromed....

Jeep 2.5 Liter, four-cylinder engine, chromed. This picture of the display engine shows part of the fuel injection system (with MPFI). The fuel rail is connected to the injectors that are mounted just above the intake manifold. This engine was developed by American Motors Corporation (AMC) and continued to be manufactured by Chrysler. All were built in Kenosha, Wisconsin. (Photo credit: Wikipedia)

The unique injection system of a powerstroke engine requires that the diesel fuel injectors obtain the proper voltage supply from a driver. This is where the injector control moduleor injector driver module comes into play.

The IDM or ICM is responsible for sending the electrical current to the solenoids, which means that its basic purpose is to simply convert voltage. Together with the powertrain control module, the two components operate the fuel injection system by managing how much fuel is sent to the engine and letting the fuel injectors know when to fire.
It is of vital importance that the voltage sent to the solenoids from the ICM or IDM is correct or drivability problems ensue. A variety of things, such as corrosion, can cause problems with the driver and even result in costly repairs that are not necessary. However, a ICM or IDM that has failed or is faulty can cause the vehicle to not start at all or just stall.
Checking the voltage output lets a mechanic easily know if there is a problem with the driver.

IDM Explained

Jeep 2.5 Liter, four-cylinder engine, chromed....

Jeep 2.5 Liter, four-cylinder engine, chromed. This picture of the display engine shows part of the fuel injection system (with MPFI). The fuel rail is connected to the injectors that are mounted just above the intake manifold. This engine was developed by American Motors Corporation (AMC) and continued to be manufactured by Chrysler. All were built in Kenosha, Wisconsin. (Photo credit: Wikipedia)

A driver supplies the proper voltage to the solenoids on the fuel injectors of a Ford Powerstroke Engine. The 7.3 Ford Powerstroke Diesel uses an Injector Drive Module (IDM). The voltage provided by the IDM is critical to the performance of the fuel injectors, and therefore, the engine itself.

You should be aware that the 6.0 Ford Powerstroke diesel utilizes an Injector Control Module (ICM).

Prior to 1999, these engines used a 110 volt driver. The 1999 and newer engines utilize a 120 volt injector drive module. 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).

You can reach the IDM through the driver’s side fender. You will need to remove the fender liner to get to the IDM. Due to its location in the wheel well corrosion is oftentimes a problem. You should check the connections for any corrosion at this time.

Problems resulting from a defective IDM producing low voltage can be challenging to pin down. The engine may still run, but not run well with low voltage. When the voltage reaches a minimum, the engine will stop.

You may 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. When checking the IDM it is also a good opportunity to check for corrosion in and around the IDM, its connections and at the wiring harness. To check the condition of the harness, pull on it slightly while the engine is running. 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 to replace it.

Electronic Control Module – ECM Explained

Jeep 2.5 Liter, four-cylinder engine, chromed....

Jeep 2.5 Liter, four-cylinder engine, chromed. This picture of the display engine shows part of the fuel injection system (with MPFI). The fuel rail is connected to the injectors that are mounted just above the intake manifold. This engine was developed by American Motors Corporation (AMC) and continued to be manufactured by Chrysler. All were built in Kenosha, Wisconsin. (Photo credit: Wikipedia)

The electronic control module, or ECM, is the “brain” of a vehicle. The vehicle uses sensors to tell the ECM what is going on in the engine. It also uses some sensors to tell the engine what to do. These sensors get their instructions from the ECM.

What Does the ECM Control?The ECM controls only things related to fuel injection. A fuel injected vehicle generally runs on 14:1 — 14 parts air to one part fuel. The mixture must be perfect or the vehicle will not run properly. If the mixture is too far off, the vehicle may not run at all.

The ignition system is related to fuel injection and is controlled by the ECM. The ignition must send the spark at the proper time. A four-stroke engine has four strokes. The first stroke is the intake stroke. On the intake stroke, the pistons go down in the bore, which his then filled with the air and fuel mixture. When the pistons come back up, it is compressing the air and fuel mixture to make it ready to fire. This is the second stroke, or the compression stroke.

The third stroke is the combustion stoke. At this point, the pistons are coming back up. The ignition system fires the spark plugs, which light the compressed air and fuel mixture in the cylinders. This forces the pistons down in the bore. The camshaft opens the exhaust valves and lets the resulting gas or exhaust out. This is called the exhaust stroke.

Sensors: In order for the engine to work properly, everything must be “just so.” Sensors sense the barometric pressure outside the engine. Temperature sensors measure how hot the engine is running. There are several more sensors that sense various variables. All of this information is forwarded tot he ECM. The ECM translates the information, then tells the fuel injectors how long to stay open. The longer a fuel injector remains open, the more fuel that goes into the engine. If the air is thin, meaning less oxygen in the air, the engine needs less fuel to make up the 14:1 ratio. If the air is thicker, such as at lower sea levels, the vehicle needs more fuel to make up the 14:1 ratio.

Other sensors, such as the oxygen sensor, sense how much oxygen is in the exhaust. Much of the unburned exhaust is routed through the EGR and back into the cylinders to cool the cylinders. The ECM also senses this and uses information from the EGR to determine the proper air to fuel mixture.

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.

FORD 6.0L DIESEL INJECTOR CONTROL MODULE

 

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.

7.3L DIESEL INJECTOR CONTROL MODULE

Fuel Injection

Fuel Injection (Photo credit: J Mark Dodds [a shadow of my future self])

Introduced in 1994, the 7.3-liter Power Stroke engine uses an injector drive 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 7.3-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.

To replace the driver, access it through the driver side fender by removing the inner fender lining. Take care to ensure connections are free of corrosion before installation.

Check The Voltage Of Your Fuel Injection Control Module If Your Vehicle Doesn’t Start

An example of jacketed fuel injection pipes in...

An example of jacketed fuel injection pipes installed on a diesel engine. (Photo credit: Wikipedia)

You are running late for work. You go outside, place the key in the engine, and nothing happens. No matter how many times you turn the key to start, the engine won’t turn over when it is cold. You don’t know what the problem could be.

Well, one problem may involve the Fuel Injection Control Module (FICM). The FICM has a voltage of 48 volts as it fires the injectors. If the voltage falls too low, the injectors will not fire. You can perform a FICM check to see how much voltage it has.

Checking the FICM

It’s best to check the FICM when the engine is cold and you have someone who can help. You should move the coolant reservoir to give you room. You don’t have to fully disconnect the hoses. Just remove the two bolts holding the reservoir to the cowl and push it to the side.

Remove the two screws on the lid of the FICM and take it off. When you look inside, you will either see 4 screw heads or 7 screw heads depending on the year your truck was manufactured. With a multi-meter, set it to DC volts and place it on the far right screw if there are only 4 screw heads. When testing 7 screw heads, place the multi-meter on the screw on the far left in the top row of four screws. Never allow the multi-meter’s probe touch the case.

Have your assistant turn the engine key without starting the vehicle up. With the key ON, test the voltage. If the voltage is 46 or more, the FICM is fine. If it ever drops below 36, then something is seriously wrong with your FICM.

Tell your assistant to cycle the key as you continue to check the voltage during the key-on buzz test, it should not drop below 46 volts. Turn over the engine and check to see if the FICM maintains its voltage. If it does, your FICM is fine and you can troubleshoot other areas to determine the engine problem.