I have a 2002 F250 7.3 that after starting and letting it run at idle the oil pressure gauge will drop to 0 and the check guages light will come on. usally happens after 2 to 5 minutes of running. Truck is full of oil and continues running.

 

If the truck is still running you have oil pressure. HEUI injectors need high pressure oil to work. No oil pressure, no run. Need to check gauge for proper operation.

 

that was my understanding , that it would shut down if it lost oil pressure. This is my first deisel

 

Yes that is the case with our HEUI engines. I don't know if there is a fail safe of some sort on the peizo electric version.

 

There is no Stock Monitoring System for the HPOP System.

The Oil Pressure Gauge on our vehicles monitors the Low Pressure or Engine Lubrication portion of the System.

It is possible to have a Low Pressure Pressure issue and still supply Oil to the HPOP.

I would begin by putting a Mechanical Gauge where the Sending Unit is an monitor. at a MINIMUM you require 12 psig at Idle to facilitate sufficient Lubrication.

If that "Passes the Test". Check the Sensor, Connector, Wiring, and suplimental Connections until you identify the problem.

 

where is the sending unit

 

why would the oil pressure be normal at start up and then drop all at once. reving the engine has no affect on the pressure reading. at start up the gauge immeditly goes to mid range on the gauge

 

The sensor that's atop the hpop resivoir...get yourself a #4orb(m) X 1/8npt(f) adaptor from a hydraulic shop. Then get a liquid filled 100psi gauge and a 9" grease gun hose. Acquire a 1/8npt coupling and now, you have yourself an oil and fuel pressure tester

 

would that check the low pressure issue mentioned above

 

Absolutely....

 

First thing that comes to mind is low voltage or a stall/stutter?

Do you notice a stumble, or a quick catch to keep running when this happens?

 

The Sending Unit is atop the HPOP Reservoir as stated. Part# 9378

Q: Why would the oil pressure be normal at start up and then drop all at once.

A: A defective Sensor, failing Oil Pump, Viscosity Change.

Q: Revving the engine has no affect on the pressure reading.

A: A defective Sensor, failing Oil Pump, Viscosity Change.


Q: At start up the gauge immediately goes to mid range on the gauge.

A: These are Analog Thermistor Units. They do not graduate in small increment. The generally sweep from, for example: Mid Range to HOT on Cooling - They're not graduated, they either are, or are not.

 

a final question. would it be safe to drive or am I going to burn the engine up??

 

I would certainly insure that I had verified readings before doing any serious driving.