Ford's answers to the NHTSA 6.7 Investigation
There was a request for a link to Ford's answer's to the NHTSA investigation posted on a previous thread, since closed. Here is the link: Ford's NHTSA Answers to the 6.7 investigation This PDF i...
Forum Discussion
Hi all,
Here's a part of the Fuel System explanation from the Coffee Table book:
FUEL SYSTEM
At key on, the fuel pump within the Diesel Fuel Conditioning Module (DFCM) is turned on and the low pressure fuel
system is pressurized. If the engine is not started, the pump runs for up to 30 seconds. The PCM obtains information from
the Ambient Air Temperature (AAT), Engine Coolant Temperature (ETC) , Engine Oil Temperature (EOT) , and Fuel Rail
Temperature (FRT) sensors for fuel delivery calculations. The Volume Control Valve (VCV) and Pressure Control Valve
(PCV) are open.
During engine cranking the PCM identifies Top Dead Center (TDC) within approximately 120 degrees of crankshaft
rotation and PCV is closing, allowing fuel pressure in the rail to achieve the calibrated value. This allows the engine to
start very quickly.
Once the Fuel Rail Pressure (FRP) sensor detects the required fuel pressure, the PCM begins fuel injection operation to
meet the desired idle RPM based upon the temperature sensors and engine load. During this initial start up mode, the
high pressure fuel system is run in PCV mode for a calibrated amount of time. The VCV is set to a specified point while
PCV is duty cycled to meet the desired fuel rail pressure.
The high pressure fuel system operates in PCV mode until a calibrated fuel temperature and time is achieved.
In VCV mode the fuel volume entering the high pressure fuel pump is adjusted by the VCV to meet the required fuel rail
pressure while still being trimmed by the PCV. VCV mode is a more efficient operating mode because only the amount of
fuel required for combustion is being compressed by the pump and sent to the fuel rails.
During acceleration, the VCV and PCV are commanded to meet the driver’s demand (accelerator pedal input/engine
load). The PCM’s commands to the VCV and PCV are based upon: FRT, ECT, EOT, ATT, engine load, and regeneration
state.
On deceleration, the VCV is closed and the PCV is opening to max position to reduce fuel pressure. When RPM is
approaching the desired idle speed, the VCV begins to open to prepare for injector usage.
During regeneration, the left side injectors perform post injection. The right side injectors do not provide fuel for
regeneration because right side cylinders supply exhaust gas to the EGR valve and EGR cooler.
Under certain conditions, like battery disconnect and fuel system reset, the fuel system operates in Adaptive PCV (APCV)
mode on the first start. In the APVC mode, the PCM is learning the duty cycle needed for the PCV to achieve the desired
fuel pressure.
I have always wondered if the Volume Control Valve has been a piece of the puzzle. Also don't forget that these engines can be spinning 3500- 4000 rpm in Engine Brake mode with the VCV closed on a good downhill while towing.
To answer a few on going questions,
The HPFP is gear timed to injection events for pressure stability.
There is an area in the left fuel rail which acts as a damper for pulses. Left rail feeds the right rail.
The inlet fuel pressure is regulated to 100 psi from the DFCM pump.
From day one I felt the corrosion shown in some pictures of the fuel system parts was caused by the acids in Bio firing off the mild steel of the fasteners etc. I wonder if some of the deposits in the rails shown by Ford are actually the lacquer discussed in some of the papers and not corrosion.
I would love to see pictures of Ricatic's pump carnage, I imagine he has something which is keeping him from posting them.
As far as counting the odds, imagine what the odds are on a husband and wife both being diagnosed with MS 12 years apart. A virtual Father of Modern Neurology at the Mayo in Rochester guessed in the billions, but it is my reality. Pardon me if I hesitate to gamble.
I really have had my truck be trouble free and like it alot, but a 10-15k hit means no meds for a while at 1208.00 a month, not pretty. The fact that the failures are so rare is even more frustrating as to why Ford won't belly up to the bar.
This is the Achilles heel for these trucks.
Mark
Here's a part of the Fuel System explanation from the Coffee Table book:
FUEL SYSTEM
At key on, the fuel pump within the Diesel Fuel Conditioning Module (DFCM) is turned on and the low pressure fuel
system is pressurized. If the engine is not started, the pump runs for up to 30 seconds. The PCM obtains information from
the Ambient Air Temperature (AAT), Engine Coolant Temperature (ETC) , Engine Oil Temperature (EOT) , and Fuel Rail
Temperature (FRT) sensors for fuel delivery calculations. The Volume Control Valve (VCV) and Pressure Control Valve
(PCV) are open.
During engine cranking the PCM identifies Top Dead Center (TDC) within approximately 120 degrees of crankshaft
rotation and PCV is closing, allowing fuel pressure in the rail to achieve the calibrated value. This allows the engine to
start very quickly.
Once the Fuel Rail Pressure (FRP) sensor detects the required fuel pressure, the PCM begins fuel injection operation to
meet the desired idle RPM based upon the temperature sensors and engine load. During this initial start up mode, the
high pressure fuel system is run in PCV mode for a calibrated amount of time. The VCV is set to a specified point while
PCV is duty cycled to meet the desired fuel rail pressure.
The high pressure fuel system operates in PCV mode until a calibrated fuel temperature and time is achieved.
In VCV mode the fuel volume entering the high pressure fuel pump is adjusted by the VCV to meet the required fuel rail
pressure while still being trimmed by the PCV. VCV mode is a more efficient operating mode because only the amount of
fuel required for combustion is being compressed by the pump and sent to the fuel rails.
During acceleration, the VCV and PCV are commanded to meet the driver’s demand (accelerator pedal input/engine
load). The PCM’s commands to the VCV and PCV are based upon: FRT, ECT, EOT, ATT, engine load, and regeneration
state.
On deceleration, the VCV is closed and the PCV is opening to max position to reduce fuel pressure. When RPM is
approaching the desired idle speed, the VCV begins to open to prepare for injector usage.
During regeneration, the left side injectors perform post injection. The right side injectors do not provide fuel for
regeneration because right side cylinders supply exhaust gas to the EGR valve and EGR cooler.
Under certain conditions, like battery disconnect and fuel system reset, the fuel system operates in Adaptive PCV (APCV)
mode on the first start. In the APVC mode, the PCM is learning the duty cycle needed for the PCV to achieve the desired
fuel pressure.
I have always wondered if the Volume Control Valve has been a piece of the puzzle. Also don't forget that these engines can be spinning 3500- 4000 rpm in Engine Brake mode with the VCV closed on a good downhill while towing.
To answer a few on going questions,
The HPFP is gear timed to injection events for pressure stability.
There is an area in the left fuel rail which acts as a damper for pulses. Left rail feeds the right rail.
The inlet fuel pressure is regulated to 100 psi from the DFCM pump.
From day one I felt the corrosion shown in some pictures of the fuel system parts was caused by the acids in Bio firing off the mild steel of the fasteners etc. I wonder if some of the deposits in the rails shown by Ford are actually the lacquer discussed in some of the papers and not corrosion.
I would love to see pictures of Ricatic's pump carnage, I imagine he has something which is keeping him from posting them.
As far as counting the odds, imagine what the odds are on a husband and wife both being diagnosed with MS 12 years apart. A virtual Father of Modern Neurology at the Mayo in Rochester guessed in the billions, but it is my reality. Pardon me if I hesitate to gamble.
I really have had my truck be trouble free and like it alot, but a 10-15k hit means no meds for a while at 1208.00 a month, not pretty. The fact that the failures are so rare is even more frustrating as to why Ford won't belly up to the bar.
This is the Achilles heel for these trucks.
Mark
