Does the car have a hard time accelerating (especially on the highway)? Is your car showing signs of low fuel? The fuel line, filter, pump or injector is most likely blocked or partially blocked. If you can’t start your car at all, you might want to do a quick fuel pump test to see if that’s the culprit.
1.Conduct electrical testing
①Check fuel pump fuse.
Often it is not the fuel pump that fails, but the power supply. Consult the owner’s manual to find the location of the fuse box, and then find the fuse that corresponds to the fuel pump. Remove the fuse and check for signs of failure. Fuses may melt or blow. If the fuse appears to be OK, check other fuse parts associated with the fuel system for signs of wear and replace them if necessary.
·If you need to replace the fuse, make sure to use one with the proper current rating. Do not install a fuse with an excessively rated current.
·A blown fuse could mean that the circuit is drawing too much current, and you need to check individual circuits. When checking the relay, get someone to start the car for you, or take it to a repair shop.
②Check fuel pump voltage.
The current flowing through the circuit won’t necessarily go to the fuel pump, so you’ll have to check the voltage too. Look through your car’s manual to see which parts you need to inspect and the correct inspection procedure.
·Test the voltage source to see if current leaves the fuse to the fuel pump.
③Use a voltmeter to perform a voltage drop test.
Make sure the wires have enough voltage and the ground wire is properly grounded. If the electrical test results show that everything is OK, it is likely that the fuel pump is faulty and needs to be replaced. You can additionally perform an oil pressure test for a more comprehensive check.
·If the voltage difference exceeds 1 volt, the wire may be corroded, or there may be a problem with the positive or negative side of the circuit. Take it to a repair shop for more in-depth testing and further advice.
2.Carry out an oil pressure test
①Possibility of drain filter failure.
A clogged filter with sediment can also make it difficult for the car to accelerate (and you suspect the problem is the fuel pump). Check the short inlet hose and blow air into it to make sure there isn’t much resistance. Check the filter screen for debris and replace the filter if necessary.
②Buy a fuel pressure gauge.
Most auto parts stores sell fuel pressure gauges. It’s a good investment, and it works on most models. If you don’t want to buy it, you can also borrow it from a mechanic or auto store that allows customers to borrow tools. The oil pressure test only takes a few minutes to complete.
③Connect the pressure gauge to the fuel pump assembly.
Find where the fuel pump is located (usually near the carburetor or injector) and find where the fuel pump connects to the filter housing. There should be a small connector there to connect a pressure gauge.
·Each gauge may be used slightly differently, and the location of the fuel pump varies from car to car, so consult your car’s manual for more details.
④Get someone to start the engine for you while you check the pressure gauge.
Let the engine warm up a little and check the oil pressure when the car is running at idle and rated rpm (see fuel pump specs). If you don’t know the rated rpm, just start the engine and see what the oil pressure makes a difference. If the problem is serious and the needle on the pressure gauge doesn’t move, then you need to replace the fuel pump.
·The oil pressure must meet the specifications listed in the owner’s manual, and when the engine runs to a certain level, the oil pressure should also increase. If the oil pressure does not increase, or the difference between the inlet and outlet pressures exceeds 28 kPa (4 psi), then you need to replace the fuel pump.
