What causes high fuel rail pressure at idle?
1) Open or poor connections at the MPROP (FPR) connector-pigtail or main engine harness connector will cause loss of pressure control, maximum rail pressure at idle. 2) A stuck MPROP (FPR) can cause excessive rail pressure. 3) Bad suction valves in the high pressure pump can cause rail pressure to be excessive.
What was high fuel rail pressure in 2002?
2002 LB7 High fuel rail pressure at idle. HELP Replaced CP3 Injector pump,came with new pressure regulator. And replaced all injectors. I was dealing with diesel dilution in the oil. Found a cracked injector and solved that problem.
What causes low fuel pressure in an engine?
1 Clogged Fuel Filter The fuel filter cleans the fuel entering the engine. 2 Bad Fuel Pump A bad fuel pump is probably the most common cause of low fuel pressure. 3 Bad Fuel Pressure Regulator The fuel pressure regulator controls the fuel pressure in the fuel rail.
What happens if the fuel pressure regulator fails?
The fuel pressure regulator controls the fuel pressure in the fuel rail. If there is something wrong with the fuel pressure regulator, it can create too low or too high fuel pressure in the rail. It is not very common that this part fails, but it can happen.
What should fuel rail pressure be at idle speed?
The pressure regulator has a sense line that is attached to the intake manifold, to measure manifold pressure. As the manifold pressure decreases and increases so too does the fuel pressure. With the motor running at idle speed the fuel rail pressure is supposed to be approximately 36.3 psi.
Where is the fuel pressure test port on a Ford 4.6L?
These instruction pertain to Ford 4.6L 2-valve, 4.6L 3-valve, 5.4L 3-valve and 6.2L 2-valve engine. It shows where the fuel pressure test port is and how to test. On a 4.6L 3-valve, unscrew the Evaporative Emission purge valve bracket and move the bracket to the side. That will allow access to the fuel test port
What should the intake manifold pressure be at idle?
The intake manifold pressure will be nominally 15 psi which results is a pressure differential of 40 psi (55 psia minus 15 psia = 40 psia). The motor is started and run at an idle in which case let’s say the intake manifold pressure drops to 6 psi.