How To Tell If Your Fuel Pump Needs Replacing
Fuel Pump Assembly 1986 Bronco II CC Image courtesy of Marion Doss on Flickr
Your fuel pump is obviously important for your car, and it would seem as if your vehicle couldn’t move without one. That’s not always true, though. Some vehicles can limp along with a malfunctioning fuel pump for a few blocks or even miles.
But driving with a poorly performing fuel pump is not good for your vehicle, so it’s important to look out for some signs of trouble before you end up stranded or stalled out in traffic.
If the name isn’t descriptive enough for you, the fuel pump pumps fuel from your vehicle’s tank to the engine. It follows that if the fuel pump malfunctions, your engine will receive less fuel than it needs. There are some common symptoms for such a situation.
The first and most obvious symptom is that your car may not start at all, or it might start poorly. This poor start will take the form of a sputtering, stuttering, stammering sort of start, as if your car’s engine is only getting a trickle of fuel instead of the amount it needs. Your car may also stall during operation because the fuel pump is bad.
Vehicles can sputter and stall for a variety of reasons, so here’s a follow-up test. Pull your vehicle in the garage or other silent environment. When it’s not running, put the key in the ignition and turn it to the “ON” or “accessory” position. (Don’t try to start the engine.) If you have fuel injection and an electric fuel pump, the pump should start up, making a clicking or buzzing sound.
After performing the above test, if you can’t hear the fuel pump turn on, try this test. Using a fuel pressure gauge, test to make sure there’s enough fuel reaching the engine. You can take your vehicle to a technician for this test, or purchase a fuel pressure gauge at an auto parts store and do it yourself. Near the engine there should be a fuel pressure valve where you can attach the gauge. Find the recommended fuel pressure in ChiltonDIY. Compare your measurement of the fuel pressure with what it should be. If there is less pressure than there should be, that’s a sign that your fuel pump may be faltering.
Of course, there could be a few other problems causing incorrect fuel pressure: an obstruction in the fuel line or a bad fuel pressure regulator. If your fuel pressure is too high, suspect the fuel pressure regulator. For more information on diagnosing a fuel pump problem, check out Chilton’s online database of vehicles for detailed instructions, images, and specific tips from our certified expert technicians on determining whether you need to replace your fuel pump, fuel pressure regulator, clean out the fuel lines, or something else. Learn more about how to keep your car in tip top shape!
My engine in my truck, when sitting for three to eight hour, will not start when turn the ignition on,but will start on the second try and their after, only when it sit’s a long time.
Hi Hamp.
It sounds like a bad fuel pump regulator. Is it a Chrysler product? Install a fuel pressure gauge on the vehicle’s fuel system, and then check the running pressure. Turn of the vehicle off. With the fuel gauge installed check to see if the fuel pressure slowly drops off. If it does you may be dealing with a faulty fuel pressure regulator.
If you have a leaking injector causing the problem, you will have a fuel smell, blue smoke and a possible misfire when trying to start the vehicle.