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FASS for EcoDiesel


New Member
Mar 2, 2022
Truck Year
Good day,
A FASS kit was installed on 2016 RAM EcoDiesel and it never worked properly. FASS did replace the electric motor on the FASS pump. Now the CP4 injection pump is suspect for failure. There are no codes associated. The high pressure pump is not producing pressure, via a Snap On scan tool. Next is to replace the CP4 injection pump. Any assistance will be appreciated.
Thank you,


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TC Diesel

Well-Known Member
Jul 14, 2016
Truck Year
Was the Factory fuel filter removed? if it was it's another FASS Failure...The CP4 on VM 3.0 are NOT equip with GP Gear pump, any external Electric pump will NOT equal the Factory OEM in tank Pump You NEED 55PSI to properly feed the COV and internals on CP4s W/O GP....