1999 Ford F-250 injector rail pressure

Sorry, but I'm not a diesel expert. However, I figured I would try to help. Is the fuel pump pressure within the manufacturer's specs? Are you getting any pressure at all? Filters?

I found this information about the fuel pressure. It appears there is a low pressure pump that supplies aprox 55psi of fuel pressure to the injectors. Read this article and let me know if it helps.

HEUI Hydraulically actuated, Electronically controlled, Unit Injector. So what exactly does that mean? It means that from 1995 through 2007 ALL Ford light and medium duty diesel trucks did not have an injection pump. None, nada, zip. This is in fact one of the HUGE factors in favor of using a Powerstroke for biofuels. It is impossible to cause a catastrophic failure by breaking the injection pump because it does not exist. Each Injector is in fact its own Injection Pump. Although the design changed a bit between the 7.3 and the 6.0, the basic concept is the same. Each unit injector basically has two sections- One for fuel, and one for high Pressure engine Oil. Unless there is a mechanical failure the two fluids should never contact each other. The fuel provided by a low pressure fuel pump( 55psi), and the Engine Oil is delivered by a High Pressure Oil Pump(HPOP). The HPOP uses low pressure crankcase engine oil and pressurizes it to between 500 and 3000psi based on the duty cycle of the IPR(injection pressure regulator) that is controlled by the PCM(Powertrain Control Module).

I found this info too.

"Regardless of year, anything south of 50 psi and you may not get complete injector filling."

I think we need to check the low pressure pump.

Sorry for so many posts. I am reading things and they are prompting questions. According to the info I read, special engine oil needs to be used to avoid aeration. Read this article about engine oil.

"The most common problem with Ford's 7.3 Direct Injection Turbo diesel is related to engine oil change interval and type of oil being used. It is critical for proper engine operation that the customer or technician servicing the vehicle check that the correct oil is being used. This engine uses a high pressure oil pump to operate the fuel injectors. Typical system pressures are 500 psi at idle, 1200 at 3300 rpm in neutral, and 3600 psi at full load acceleration. Oil for the PowerStroke requires an anti-foaming agent to prevent the oil from aerating, which would result in poor fuel injector spray patterns and reduced power. Depending on vehicle usage, the anti-foaming agents are depleted in 3000-5000 miles.

The only oil recommended for the PowerStroke by Ford is Motorcraft Super Duty 15W40, 10W30. Each of these has the proper additives in them for use in a diesel engine including the anti-foaming agents. The 15W40 is recommended for normal climates, the 10W30 for temperatures below 20 degrees fahranheit. For temperatures below -10 degees, 5W-30 is recommended. There are other oils, however, that do meet all the requirments for use in the PowerStroke. The specifications the owner needs to look for on the label are the API rating of CF-4/SH or CG-4/SH or higher. Some other oils with the correct"

I hope I am helping and not causing more problems.

I'm glad to help. Has any of the info I sent helped or made any sense related to your problem?