What causes low voltage to fuel pump?
The voltage drop occurs because of resistance in the circuit that supplies the pump. The resistance could be in the connectors, grounds or harness. A resistor or insulator prevents the flow of electricity in a circuit. Resistance can be caused by corrosion, fretting and even air.
Can an electric fuel pump get weak?
Because of how they operate (constantly running whenever the ignition is turned on) over time fuel pumps can eventually wear out and weaken. A weak fuel pump may still pump fuel, however the vehicle may experience difficulty starting as a result of the lack in pressure.
How many volts does a fuel pump need to work?
System voltage should read 11.8 – 12.6v DC or higher with no electrical loads on the system. If voltage reads less, starting and charging system should be investigated before performing fuel system electrical testing. 1. Connect digital voltmeter to fuel pump wiring at fuel pump connector.
Why is my electric fuel pump not working?
Someone else needs to turn the key because the fuel pump will hum for just two or three seconds if it’s working. If the pump makes no sound, the good news is the cause might be a blown fuse. Locate the fuel pump fuse and relay. If it’s blown, replace the fuse with another of the same amperage.
Can a fuel pump have a voltage drop?
Fuel pumps and voltage drops are never a good combination – at least the wrong kind of voltage drops. Good voltage drops occur with fuel pumps that are given multiple speeds with a module that is connected to a computer with a dedicated signal wire that tells the module to go to a lower or higher speed.
What should I do if my fuel pump is not working?
Fuel pump breakers usually have a button on top that pops up when it trips. Simply push this button back in until it clicks. Check the owner’s manual for the exact location. Fuel Pump Testing – If the fuse is good and the circuit breaker is not tripped; then the engine is not getting fuel pressure.
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.
Why does my car only have 12 volts at the pump?
Turns out it was the computer. You’re only going to see 12+ volts at the pump just like at the inertia switch for two seconds after the ignition’s turn to run and then it’ll drop back down and it won’t go back up again to 12+ until the motors turning 400+ RPMs . The two second 12Volt hit is just to prime the pump.