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.