The 7.3 ICP sends the current pressure reading to the Powertrain Control Module (PCM) which in turn signals the 7.3 Injection Pressure Regulator (IPR) to add or reduce pressure.
The three of them, along with the 7.3 HPOP, provide enough oil pressure to the oil rails so that when you press on the accelerator, your 7.3 injectors actuate, your engine gets diesel and the cylinders fire … ideally, as smoothly as possible.
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One quick way to diagnose a failed 7.3 ICP Sensor is to lift the plastic clip on the wiring connector and remove the pigtail from the sensor. If there’s oil on the sensor’s plug receptacle, its leads, or around the pigtail connector, you’ve got a failed ICP sensor.
Just what does the ICP sensor on a 7.3 Powerstroke do?
In a diesel engine as heavily-reliant on adequate and correct oil pressure as the 7.3 HEUI system is, the 7.3 PCM needs instant and accurate information on the amount of pressure in the 7.3 oil rails. This is so that the PCM can determine how much pressure, at any given second, to deliver to the injectors for maximum fuel firing efficiency.
Broken down, the 7.3 Injection Control Pressure sensor tells the PCM what the oil pressure is in the driver’s side oil rail. It uses a five volt signal and returns it to the PCM. This analog voltage signal to the PCM tells it how much pressure’s in the oil rails.
And in conjunction with the 7.3 IPR, HPOP, and PCM, the Injection Control Pressure Sensor on your 7.3 provides this pressure information feedback in a continuous loop.
Broken down and simplified, these are the four components on your 7.3 Powerstroke diesel that regulate oil pressure in order to accurately and efficiently actuate your injectors enabling them to fire and create combustion.
If, or should I say when, your 7.3 ICP fails, the PCM in your truck won’t know how much pressure’s in the oil rails and it won’t be able to regulate that pressure to efficiently actuate the injectors, resulting in poor engine performance.
What will actually happen is that it will get incorrect data from your 7.3 ICP and then deliver incorrect oil pressure, causing at best rough-running and at worst a no-start condition.
But let’s not get ahead of ourselves.
As mentioned above, the 7.3 ICP sensor measures pressure from the oil rail. Over time, all that oil pressure on your ICP pushes and exerts force on the sensor’s internal components and plastic electrical connector housing. A couple hundred thousand miles of that and it’s bound to fail. When it does, the oil will cause bad electrical readings as well as corrode the sensor’s ability to send those signals.
With your engine running, pull the connector, disconnect your 7.3 ICP pigtail. This causes the PCM to deliver a default ICP value of 725 PSI at idle. As apposed to the stock setting of 500-550 PSI at idle. There should be a noticeable difference in idle when you unplug your ICP.
If you don’t feel a difference, your 7.3 ICP is most likely already running on this default setting. This could mean that your ICP is bad.
Now, some people do this, but I wouldn’t recommend running your 7.3 without ICP readings. The sensor’s there for a reason. Replace it if it’s bad.