How does the PCM control the fuel pump?
How does the PCM control the fuel pump?
After the ignition switch is returned to the “ON” position, power to the fuel pump is supplied through the fuel pump relay. The PCM monitors engine speed and opens the fuel pump relay ground circuit if the engine speed drops below 120 rpm.
How does the PCM know if the engine is running?
The PCM looks for an rpm signal from the engine to know if the engine is running or not. If it sees no rpm signal, it assumes the engine is off or has quit running and shuts off the fuel pump.
How does the fuel pump work on a Ford truck?
On late model Fords, there is a fuel pressure sensor but not on your truck. The PCM keeps the fuel pump relay energized for a second or two while the engine is cranking, then cuts it off the relay the engine does not start. If the engine starts, it keeps energizing the relay to run the pump.
How does the fuel pump relay work in a car?
When the ignition switch is turned ON, the Electronic Engine Control (EEC) power relay is energized, providing power to the fuel pump relay for 1 to 2 seconds through the Powertrain Control Module (PCM) and an Inertia Fuel Shutoff (IFS) switch.
After the ignition switch is returned to the “ON” position, power to the fuel pump is supplied through the fuel pump relay. The PCM monitors engine speed and opens the fuel pump relay ground circuit if the engine speed drops below 120 rpm.
The PCM looks for an rpm signal from the engine to know if the engine is running or not. If it sees no rpm signal, it assumes the engine is off or has quit running and shuts off the fuel pump.
When do you turn on the fuel pump?
When you turn the key… When you turn the key to On, the fuel pump may run from 2 seconds to 2 minutes before it turns off. We replaced the PCM module, ignition control module, fuel filter, PCM diode with no luck. It seems like the longer the truck sits, the worse the problem.
When the ignition switch is turned ON, the Electronic Engine Control (EEC) power relay is energized, providing power to the fuel pump relay for 1 to 2 seconds through the Powertrain Control Module (PCM) and an Inertia Fuel Shutoff (IFS) switch.
Why does the fuel pump relay not stay on?
The relay is weak and is not staying on when it is energized by the PCM. When the engine is running, the extra charging voltage may be enough to hold the relay on. The relay is located in the power distribution box under the hood. Here’s a description of the fuel pump relay circuit from the Ford SZservice literature.
Can a fuel pump run with no power?
The pump is simply a motor. If the power is turned on to the motor, the motor will run…no power, it won’t run. Unless the relay or PCM sends a signal to the pump and waits for a response before the relay/PCM would shut off the power, it does not seem logical that the issue would lie at the pump. I do not know if this is the case.
How to check for a faulty fuel pump?
THIS WILL POWER THE PUMP TO RUN AND CHECK FOR A FAULTY FUEL PUMP. 3. NEXT, CHECK FOR FUEL PUMP SIGNAL AT THE FUEL SYSTEM CONTROL MODULE. 4. FIND THE DARK GREEN/WHITE WIRE IN PIN13. WITH A TEST LIGHT CONNECTED TO THAT WIRE, TURN THE KEY TO THE RUN POSITION.
What to look for in fuel system control module?
AFTER COMPLETING THE STEPS ABOVE, IF YOU FIND NO POWER AT THE FUEL SYSTEM CONTROL MODULE, AT THE DARK GREEN/WHITE WIRE, MOVE TO THE POWERTRAIN CONTROL MODULE. AT THE POWERTRAIN CONTROL MODULE, CHECK PIN 50, IN THE BLACK CONNECTOR, FOR 12 VOLTS WITH THE KEY ON, FROM THE DARK GREEN/WHITE WIRE.
Where is the fuel pump control module located?
It is often found in the fuse box located in the engine bay and functions as the primary electronic switch that controls power to the fuel pump. The fuel pump relay is usually controlled by the ignition or Powertrain Control Module, and when switched on, will provide current to the fuel pump so that it may function.
It is often found in the fuse box located in the engine bay and functions as the primary electronic switch that controls power to the fuel pump. The fuel pump relay is usually controlled by the ignition or Powertrain Control Module , and when switched on, will provide current to the fuel pump so that it may function.
AFTER COMPLETING THE STEPS ABOVE, IF YOU FIND NO POWER AT THE FUEL SYSTEM CONTROL MODULE, AT THE DARK GREEN/WHITE WIRE, MOVE TO THE POWERTRAIN CONTROL MODULE. AT THE POWERTRAIN CONTROL MODULE, CHECK PIN 50, IN THE BLACK CONNECTOR, FOR 12 VOLTS WITH THE KEY ON, FROM THE DARK GREEN/WHITE WIRE.
THIS WILL POWER THE PUMP TO RUN AND CHECK FOR A FAULTY FUEL PUMP. 3. NEXT, CHECK FOR FUEL PUMP SIGNAL AT THE FUEL SYSTEM CONTROL MODULE. 4. FIND THE DARK GREEN/WHITE WIRE IN PIN13. WITH A TEST LIGHT CONNECTED TO THAT WIRE, TURN THE KEY TO THE RUN POSITION.
