Where does a low voltage fuel pump come from?
Low voltage to the pump can only be from a low voltage at the source or a resistance in the circuit (“dropping” voltage). The only possible places for a resistance are connections (which could be anywhere including a corroded fusebox terminal), relay contacts corroded (but you’ve already changed that) or internal to the inertial switch.
What does 0.1 mean on a fuel pump meter?
If the meter indicates a reading of more than 0.1 then this indicates a loss of voltage power. The reason for the loss could be damaged harness connectors or poor wiring. Connect the digital multimeter to the positive terminals of the pump and the battery.
Why is my Ford fuel pump not working?
So, to make the long story short, the fuel pump, the fuel pump relay and the fuel pump Inertia Switch are NOT the cause of your Ford’s no start problem. CASE 2: The 12 V. test light DID NOT come On and the fuel pressure WAS NOT at specification.
How to test fuel pump in Ford 4.9L?
For a step-by-step explanation on how to test the fuel pump, check out this tutorial: How To Test The Fuel Pump (Ford 4.9L, 5.0L, 5.8L). NOTE: You can run down to your local AutoZone or O’Reilly Auto Parts and rent one or, you can buy one online. You can check out the following link: Actron CP7838 Professional Fuel Pressure Tester
Low voltage to the pump can only be from a low voltage at the source or a resistance in the circuit (“dropping” voltage). The only possible places for a resistance are connections (which could be anywhere including a corroded fusebox terminal), relay contacts corroded (but you’ve already changed that) or internal to the inertial switch.
Can a voltage drop test be done on a fuel pump?
TESTING VOLTAGE DROPS. A voltage drop test is the only effective way to find excessive resistance in high-amperage fuel pump circuits. With the right leads and back-probes, it’s possible to do the test (if you have access to the top of the tank) without any disassembly.
Where is the inertial fuel shutoff switch located?
The inertial fuel shutoff switch is between the relay and the fuel pump. The pink/black wire from the inertial switch to the fuel pump should have 12 volts. You can measure the voltage, on the pink/black wire, at the fuel pump.
What should the voltage be at the fuel pump relay?
You should have 12 volts at the dark green/yellow wire at the fuel pump relay. The inertial fuel shutoff switch is between the relay and the fuel pump. The pink/black wire from the inertial switch to the fuel pump should have 12 volts. You can measure the voltage, on the pink/black wire, at the fuel pump.
You should have 12 volts at the dark green/yellow wire at the fuel pump relay. The inertial fuel shutoff switch is between the relay and the fuel pump. The pink/black wire from the inertial switch to the fuel pump should have 12 volts. You can measure the voltage, on the pink/black wire, at the fuel pump.
Why are heavy duty connectors used in a fuel pump circuit?
Voltage in the circuit is reduced “downstream” of the high resistance, so this reduces the voltage that reaches the pump motor. That’s why heavy-duty connectors are used in a fuel pump circuit. There are two fuel pressure specifications for every vehicle: system pressure and hold pressure.
The inertial fuel shutoff switch is between the relay and the fuel pump. The pink/black wire from the inertial switch to the fuel pump should have 12 volts. You can measure the voltage, on the pink/black wire, at the fuel pump.