I have 2005 ford F450 6.0 turbo disel that want start . I have change fuel pump , crac sensor , cam sensor and glow plugs it want start but if I spray starter fluid it will start but when I cut off it will not star back up please help...

. Remove and fully charge both batteries. Clean battery terminals and cable connections. Check cables for hidden corrosion and breaks.

. Check all under hood and under dash fuses with a test light or multimeter.

. Check for codes.

. Ensure engine oil is full and that the oil and filter have been recently changed. On Ford PSDs, I recommend only using Motorcraft oil and fuel filters. Alternative filters can adversely affect fuel pressure.

. 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.

. Check glow plug relay (GPR). Ensure the engine is cold, so that the PCM will tell the GPR to turn on. If the engine is hot, you won’t have as much time to check. Locate the GPR, which is often behind the fuel filter on top of the engine, slightly toward the passenger side of the valley on PSDs. There may be two relays there. If so, the rear relay is the GPR. It should have two fairly large wires (Yellow and Brown) connected to one of the large posts. With multi-meter set to DC volts, or 15V range if not auto-ranging, clip the positive (Red) lead to the output terminal (with yellow and brown wires connected), and the negative (Black) lead to ground. Turn the ignition switch to ON. If the GPR is good, it should click, and you should see 11 volts or so on the meter; then, depending on temperature, it will click off up to 2 minutes later. Do this a couple of times, to ensure it consistently makes the connection. If there is no voltage with this test, confirm by retesting as follows. Remove the two small wires from the smaller two of the four GPR terminals. With jumper wires, apply voltage from the battery across the two small terminals. If the voltmeter now reads voltage on the output terminal, the GPR is good and the problem is in the PCM circuit that tells the GPR to activate.

. Check fuel injectors. Take the valve cover off and look at each injector's exhaust, while the engine is running. Each time an injector fires, you should see oil exhausting from it. If you see oil coming out, then the injector is good. When replacing a bad injector, cut fuel, remove the glow plug, and crank the engine to get any fuel and oil out of the cylinder. If you don't, you could hydro-lock and bend a rod.

. Purge fuel filter or fuel separator of water. Do this at least monthly--daily, if necessary. Water can be a big problem with diesels, particularly in the winter. Replace fuel filter(s) every 15,000 miles. Replace under hood and under frame fuel filters.