I went out and looked at my Jeep; I see no way to gain access to change the Cascade Overflow Valve without removing the alternator and its mounting bracket.
A couple of thoughts:
1. I hope the parts/sensors you replaced are all Bosch or Mopar OEM parts. Cheap knockoffs can cause all kinds of problems.
2. What is your fuel feed pressure to the CP3? If your supply pump feed pressure is excessive, it can cause overpressure problems in the CP3 and in the fuel rail.
Hopefully some of this will be helpful in finding your problem!
Read this:Quote:
Supplying Fuel to the CP3 Injection Pump
Being a constant displacement pump means that it you can't hook just any supply pump up to it. Whereas some injection pumps can tolerate a large difference in flow rates to/through it with relatively little pressure change, the CP3 cannot. If you try to push too much fuel through the CP3 (supply pressure), the discharge pressure will skyrocket to very unsafe levels and the rail pressure will increase accordingly way beyond design pressure. There are no internal pressure relief valves in the CP3, only a direct feed to the internal supply pump. Conversely, if there isn't enough flow to it, the pressure will drop and the internal supply pump will create a vacuum (suction) in an attempt to try and supply itself enough volume of fuel to satisfy demands.
More information on the Cascade Overflow Valve:Quote:
CASCADE OVERFLOW VALVE
DESCRIPTION
The COV is located on the front cover of the high pressure pump.
The Cascade Overflow Valve has three functions:
- regulation of lubrication fuel to the internal moving parts of the high-pressure pump
- regulation of the fuel pressure being supplied to the Fuel Quantity Solenoid valve
- return excess fuel to the fuel tank
This regulated internal pressure is known as housing pressure, and is determined by engine displacement and power requirements - the 2.8L CRD requires 5bar (73psia)
For comparison, the 5.9L 6-cyl Cummins CRD requires 12.41bar (180psia)
OPERATION
The COV has a spring-loaded center spool-piece that has a drilled channel with three passages: one for initial low-pressure lubrication, one for lubrication at housing-pressure , and one for overflow. The valve is operated in three stages based on the level of pressure at the inlet.
Stage 1
When the fuel pressure entering the tip of the COV is between 0 and 3 bar (44psia), pressure is too low to overcome
regulator spring tension and fuel flows through the center channel, only . This passage always allows fuel flow through to the pump center-ring and lubricates the pump bushings and internal moving parts. This circuit also allows air to bleed during initial cranking and returns the air to the fuel tank.
The COV is in Stage 1 during cranking, only.
Stage 2
When the fuel entering the COV exceeds 3bar (44psia), but is less than 5bar (73psia), the spool-piece
moves against spring tension aligning a second passage for lubrication purposes.
Stage 2 can be reached during cranking and initial start up.
Stage 3
When fuel pressure exceeds 5bar (73psia), the spool-piece aligns with the overflow passage. This stage
relieves the pressure into an overflow circuit that sends the fuel back to the inlet side of the gearotor pump, thus limiting maximum fuel pressure to 5bar (73psia).
Lubrication fuel continues to flow through all channeled passages during this stage.
Excess fuel is sent back to the fuel tank through the fuel-return circuit
Stage 3 is reached at over-pressure
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