My low oil pressure signal appears on the dash the gausge drops to 0 at idle but goes back up when I rev the engine. I turn the engine off for a minute and restart the low oil pressure signal is gone and every thing looks OK for about 8 days and it will appear again turn engine off and it goes away

My low oil pressure signal appears on the dash the gausge drops to 0 at idle but goes back up when I rev the engine. I turn the engine off for a minute and restart the low oil pressure signal is gone and every thing looks OK for about 8 days and it will appear again turn engine off and it goes away

. Verify oil pressure on Ford PSDs with a known good mechanical gauge. Oil pressure may be too low. The cutoff will shut the engine down when the oil pressure is too low. PSDs use the Hydraulic Electronic Unit Injection (HEUI) System, so it completely relies on the oil level and condition of the oil to fire the injectors. Running the oil level low or too long can cause unusual problems.

As the name implies, the HEUI injection system uses hydraulic energy to actuate unit injectors. A PSD has two oil pumps--a low pressure lubrication pump, located near or in the front engine cover below the water pump, and a high pressure hydraulic pump, located at the front of the engine V, underneath the fuel filter assembly. If the problem persists, focus on the High Pressure Oil Pump. If the Injector Control Pressure (ICP) is lower than expected (engine cranking), it is usually caused by low injection oil pressure or regulator (IPR) valve. High pressure oil is used to pressurize and inject fuel into the cylinders--each injector is essentially its own injection pump. The IPR is a by-pass valve that controls the high oil pressure, depending on demand. The ICP Sensor monitors the oil pressure in the LH head. Check for oil in the upper reservoir--it should be within one inch of the top (add as necessary). Verify that the correct oil is being used and that it has not thinned out. For no-start concerns, check ICP Sensor readings with a scan tool or pressure gauge.

. Ensure oil and filter have been recently changed and it's filled to the top of the FULL Line.

. Use full-synthetic heavy duty diesel oil (HDDO). Installing a by-pass oil filter makes using top-quality synthetics very cost-effective, when integrated with a used oil analysis (UOA) program. All engines run better on synthetics, particularly turbo diesels. Besides significantly improved engine life, turbo life, performance, and gas mileage, synthetics promote easier starting, by allowing increased cranking speed. This last factor is particularly important in cold weather. Synthetics are also easier on batteries and starter motors. Excellent choices are:

Mobil Delvac 1 5W-40

Mobil 1 Turbo Diesel Truck 5W-40

Delo 400 LE Synthetic SAE 5W-40

Amsoil 5W-40: AMSOIL Premium API CJ-4 Synthetic 5W-40 Diesel Oil (DEO)