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James, Ford Technician
Category: Ford
Satisfied Customers: 3630
Experience:  Ford Senior Master Tech, Ford gas and diesel expert, ASE Certified
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I have a 2003 6.0 that cranks but won't start. The tach

Customer Question

Hi, I have a 2003 6.0 that cranks but won't start. The tach doesn't move when cranking, but there is no cmp sensor code and the scan tool says there is no cmp fault. The icp pressure is only 129 and the voltage is .35 volts. The ipr % is 85. I have read that the icp voltage has to be at least .8 to run, but isn't this a reading of the high pressure oil system?
Submitted: 1 year ago.
Category: Ford
Expert:  James replied 1 year ago.

If icp pressure is 129psi that is your issue. Icp needs to build up to 500psi in order for this vehicle to start and run. You could have a bad ipr valve or faulty icp sensor or icp sensor wiring.

Expert:  James replied 1 year ago.

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Customer: replied 1 year ago.
I know that's not enough pressure, but does the icp make the pressure increase or just taking a reading of the pressure? And does the ipr going to 85% while cranking indicate that it is working right? I was thinking the icp just tells what the high pressure oil pump is doing and my readings indicate a bad pump. Thanks for your help.
Expert:  James replied 1 year ago.

The icp reads the pressure the pump is building only. This is an input to the PCM. 85% IPR is to start the vehicle faster but doesn't mean the IPR valve is working correct. Diagnosis in a bad IPR valve can be tricky but they do go bad. The IPR valve is what controls the high pressure oil.

Customer: replied 1 year ago.
I have battery voltage and a good ground to the ipr, and 5 volts and good ground to the icp. I would like to keep this open until Monday. Thanks again.
Expert:  James replied 1 year ago.

If you have good power to the ipr then you can have a bad ipr valve. The way Ford tests it is with a scan tool and an air tests. The air test requires a special tool. If you remove the ipr and the screen is broken I would replace the ipr valve without question.