[rydttech]

1997 ford F-250 7.3 l diesel. Starts up then runs rough/lopes. Fault code P1211 now. IPR has been changed(oe parts). Seems ipr cannot control pressure.

[Joelk]

1997 f350 7.3 l starts and runs a bit ruff check engine light comes on!! Changed fuel filter runs bit better drive down the road seams to shut off at low revs! Then starts up fine! Already changed cam sharer sensor! Is there any other sensor that could be making it shut down?? Thanks

[TxGreaseMonkey]

Joelk:

. Check for codes with a code reader or scan tool.

. Make sure you change both the under hood and under frame fuel filters (Motorcraft only).

. Ensure engine oil and filter (Motorcraft only) have been recently changed and the oil level is up to the FULL line. This can 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.

. Replace the fuel pump, if the problem persists. Fuel pressure can drop on old, tired PSD fuel pumps, when they heat up and tolerances increase.