To confirm the pump is functioning and receiving voltage, you'll first have to perform a test of the fuel pump's electrical circuit. Start by checking the voltage at the fuel pump connector using a multimeter. A properly functioning fuel pump needs at least 12 volts to work correctly. Anything less than 11.5 volts (within automotive standards) could potentially mean that there is a problem with the electrical circuit, or wiring.
This means you want to verify the ground connection next. A weak ground can reduce productivity up to 30%, which means fuel is under-produced. According to automotive expert John Smith, “First verify the ground connection; a bad ground can seem like fuel pump failure.” If you suspect the ground, then connect one multimeter lead to the negative terminal of your battery and the other to the fuel pump ground wire. A reading of almost zero means a solid ground; however, any higher read can point out a potential issue.
Fuel Pump Relay, the function is near 80% at its best. The relay regulates the power to the fuel pump, so if this fails then is no power supplied to the pump. You can do a quick check by exchanging the relay with another of the same type and rating in the fuse box if it is similar; However, if the fuel pump turns on, you have a bad relay.
Also check if you find signs of damage on the wiring harness. The fuel pump can lose efficiency if the circuit is not continuous because frayed or corroded wires have interrupted current. According to a recent study, about 15% of fuel pump failures are due to wiring problems rather than pump failure.
It is also important to check for noise from the fuel pump working when you are troubleshooting. All fuel pumps are supposed to make a hum when activated… generally within 2–3 seconds after turning the ignition on. If the sound is missing, that could mean an electronic issue.
To diagnose the issue fully: And last but not least check with a pressure gauge to measure fuel pressure. Fuel pumps for most vehicles should maintain a pressure of 35 to 45 psi. Low pressure can also indicate the presence of electrical circuit issues that are impeding pump performance.
So as a summary, you must test all the parts to verify A Fuel Pump Electrical Circuit (supplying power): voltage, ground, relay control and wiring integrity. Fuel Pumps, when working properly, are what enable us to operate our vehicles and allow us to receive the fuel (and thus the power) we demand from our engines; therefore these tests are really important for vehicle preservation.