What amperage does a fuel pump use?
On most vehicles, a new fuel pump draws about three to five amperes of current. This amperage or current draw can be measured at the fuel pump fuse located in the vehicle’s fuse box.
How to calculate the amperage of a fuel pump?
When viewing fuel pump current waveforms on your DSO, start with a time base of either 1 or 2mS per division, and a voltage scale of 100mV per division. The waveform can be analyzed in greater detail at 1mS per division, while the rotational speed of the fuel pump can be more easily calculated at 2mS per division.
How does voltage and current affect fuel pump?
Fuel pressure and volume are influenced by voltage, current and the demand controlled by the regulator. If a fuel pump is not receiving the correct voltage, it cannot spin fast enough. Voltage drop testing can isolate problems that can still remain even if the pump is replaced.
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.
What kind of tests can you do on a fuel pump?
Some of the best diagnostic tests for fuel pumps are voltage drops and current testing. Fuel pressure and volume are influenced by voltage, current and the demand controlled by the regulator. If a fuel pump is not receiving the correct voltage, it cannot spin fast enough.
Where is the voltage on the fuel pump?
It is located at the back of the vehicle next to or in the fuel tank. It pumps fuel from the tank to the engine. The pump voltage test is important for checking the effectiveness of the fuel pump.
How do you test a fuel pump amperage?
Clamp the probe to one of the pump wires, if it’s accessible. Or clamp it around the pump’s power wire at the fuse box, at a relay or inertia switch or at an underhood test connector. While voltage may be different at various points in a circuit, current in a series circuit is the same at all points.
When does the fuel pump current draw increase?
As a rule of thumb on port fuel-equipped vehicles, fuel pump current draw increases by 1 amp for every 10 pounds of fuel pressure. An amperage level above or below the specification indicates a malfunction is present, if pressure is low and amperage is above specification.
How is an inductive AMP probe used in a fuel pump?
Inductive amp probes come in all shapes and sizes, and they can handle the full range of currents-both AC and DC. A low-amp inductive probe can be used to measure the relatively low current flow (usually below 10 amps) in a fuel pump circuit. The inductive probe converts the signal into one that can be understood by the voltage-reading DSO.