7.3 PowerStroke IDM Failure Symptoms
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The 7.3 PowerStroke is often considered among the most reliable diesel engines of all time. It certainly helps that it was built before the era of endless emissions technology. However, no engine is perfect and there aren’t any exceptions here. Ford’s 7.3 PowerStroke is still prone to its share of problems and among them is IDM failure.
The IDM has failed on my F350 two times. In this article, I’m going to discuss the symptoms I noticed when the IDM failed as well as walk you through some diagnostic steps and fixes, in addition to some general information on the system itself.
What is 7.3 PowerStroke IDM?
IDM stands for the Injector Driver Module. The 7.3 PowerStroke uses Hydraulically actuated Electronically controlled Unit Injectors – commonly known as HEUI or HUEY. Instead of using a high-pressure fuel pump, fuel pressure is achieved via high pressure oil. This is done with a poppet valve inside the injector and allows the 7.3L diesel injectors to achieve injection pressure of 20,000+psi. These poppet valves are then electronically controlled by a solenoid mounted on each injector.
Now, since the pressures are so high the solenoids require a considerable amount of power. The 7.3 PowerStroke needs about 115 volts and 8 amps to operate the poppet valves. It’s more power then the PCM can provide on its own, which is where the IDM comes into play. In essence, the IDM supplies high voltage to the solenoids to turn the injectors on and off.
How Does the Injector Driver Module Work?
The IDM operates closely with the PCM to control the fuel system. It’s the job of the Powertrain Control Module to determine the injection timing. Therefore, the PCM sends a signal to the IDM to tell it when to trigger the fuel injection. It then sends an ID signal back to the PCM.
Since the 7.3L diesel is a V8 is has two separate banks which each include 4 injectors. The IDM has two power feeds – one for each bank. When it sends power to the bank it also grounds the specific injectors ground circuit to fire that specific injector.
Diving into the specific details of IDM gets complex, and our main focus here is on IDM failures & symptoms. As such, we’ll leave it short and sweet for the operation. The above image paints a good picture of the HEUI injection system.
7.3 PowerStroke IDM Failure Symptoms
- Hard starts
- Rough idle
- Misfires
- Poor fuel economy
- Poor performance
- Excessive smoke
When the Injector Driver Module fails it can cause a myriad of symptoms. Ultimately, the IDM controls the fuel injectors and when it fails the cylinders won’t receive the proper amount of fuel. The injectors may fail to deliver fuel altogether or fuel is injected at the wrong times or amounts. Improper fuel flow is bound to lead to numerous symptoms and drivability issues.
As such, 7.3 PowerStroke IDM failure symptoms include trouble starting, rough idle, and misfires. You’ll also likely notice poor fuel economy and poor overall performance from the 7.3L diesel. Excessive smoke is a less common symptom of Injector Driver Module issues.
Common fault codes with module failure include P0261, P0273, P0279, and P0611.
Driving With IDM Failure
Is it even possible to drive the truck with IDM failure? The above symptoms assume the engine will even crank over and run. However, depending on the exact IDM issue the engine may not even turn on. In other cases, it may turn on and seem drivable at first.
Point is – issues can be a safety hazard even if the truck seems to be running OK for the most part. You likely don’t want to get caught in dangerous situations if the engine suddenly stalls and shuts off.
Frequently Asked Questions
One of the most common causes of 7.3 PowerStroke IDM failures is water intrusion. The IDM case has an air vent which is what can allow water into the case and damage the IDM. Unfortunately, the vent is important to have so don’t plug or block the air vent.
Wiring issues between the IDM unit and fuel injectors is another commonly problematic area. The wiring is exposed to hot temperatures and connectors can become brittle and break down with age. This is especially common now days considering the Ford 7.3L diesel is 20+ years old.
Replacing the 7.3 PowerStroke Injector Driver Module is about $400-600 assuming it needs to be fully replaced or remanufactured. However, you may be able to fix the issue for much less expensive. It’s possible to open the IDM and simply replace whatever is causing the issues, but it depends on the extent of the failure and the exact cause. Check out the below video for more info:
The 7.3 PowerStroke IDM failure symptoms can also be symptoms of other failures. It’s certainly possible you’re running into other fuel system, air delivery, or ignition problems. Don’t just blindly replace or take apart the Injector Driver Module without further diagnostics. Fault codes can help point you in the right direction, and always check the basics before jumping into more expensive repairs like the module.
i have a 99 F350 had a miss at 45 , was told it was injectors. they replaced them . now the truck starts hard ,once running in park you can push on peddle and rpms will go up but once you put it in drive or reverse you can push peddle to the floor and rpms will not go off 800. can you tell me what to check ?
Sorry its a7.3
this is great butif no clatter i know it could be a idmrelay or wiring but will idm cause a no clatter also
engine runs great jus no clatter and i just got the idm back from rebuilding
I have same issue with my Ford f250. 7.3. it was my husband’s and drove it daily . Had to use a batteriy out of it and then put back in. Friend moved it and it was parked with front end lower than rear. It was a cold start. My husband said I should have started bc I know what to do but unfortunately didn’t . Friend came I got me to show me had no power rmp I don’t believe even went up. Well my husband passed with weeks and truck sat for 5m bc I couldn’t emotionally handle messing with truck yet. Got it started and yes low on fuel and oil. So that in itself could be the problem but hose had to be unhooked to get it to fire over. Same isse no power would dive basically in idle speed.i “drove ” down drive way and back. Parked it til I got fuel and oil. Got both and some idiot that wants to buy it loosened the oil filter so low oil again. Did get it started but ran rough back fires and cuts out then will not restart and still hasn’t. When parked nothing mechanically wrong with truck other than small oil leak but didn’t leak enough to show on ground but half dollar size spot. Idk what they are doing to make the no start start. And the no power I’m not sure it shouldn’t have had no power it was literally just driven to begin with other than the way friend of mine parked it with front lower than rear. It dose have the extra fuel tank in back. Help Mom of 3 and a grandchild 6w old and I have no runny vehicle nor do I have income right now. Is low oil the issue? Whee do i check for water seperater ? And what hose is it that wouy vaper lock it?