Everything You Ever Wanted To Know about
EFI Fuel Pumps
(but were afraid to ask!)
Fuel Pump Troubleshooting
By Chris Myer
Answers questions such as:
What are weak fuel pump symptoms?
How Can I Tell If My Fuel Pump Died?
How to tell if a fuel pump works?
How to tell if your fuel pump is failing?
How to test a fuel pump?
How to test the fuel pump?
What are the symptoms of fuel pump failure?
How can you tell if a fuel pump is weak?
How can you tell when your vehicle needs a new fuel pump?
How can you tell your fuel pump is failing?
How do you know if you need a new fuel pump?
Let's face it--you don't want to buy a new fuel pump unless your old one has died. Likewise, we don't want to sell you a fuel pump if you don't need one. There is plenty of business for us in replacing fuel pumps that have truly failed so that we can thrive without taking your money unnecessarily. Therefore, we offer these tips on determining if your fuel pump is dead. Note! Since we only sell electric gasoline fuel pumps for fuel injected vehicles, this information is only intended to assist you in troubleshooting those sorts of vehicles.
The symptoms of a fuel pump failure include an inability for the vehicle to start or stumbling/stalling when the accelerator is depressed while the vehicle is under load. These symptoms can be witnessed in other types of problems not immediately related to fuel pump failure, so the following steps are suggested. First, in a very quiet environment, put the key in the ignition and turn it to "on" (don't start the engine.) When this is done it wil generally cause the fuel pump to operate, and fuel pumps are not typically silent. It may be necessary to do this with an assistant outside the car, but if you turn the key to the "on" position and back off several times, you should generally be able to hear the fuel pump running. This is not a litmus test for an operational fuel pump but, like many of the tests here, will give you a clue. Taken together, these clues will give you an pretty good picture of the fuel pump's condition.
Once you listen for the operation of the fuel pump, the only real way to confirm if the fuel pump is operational is to test the fuel pressure. This is done with a gauge that all good mechanics will have. In the engine compartment of the vehicle there is typically a schrader valve (like the air valve on a tire.) The fuel pressure gauge screws onto the schrader valve and lets you read the fuel pressure. How much fuel pressure? That depends on the vehicle. Use our Fuel Pump Finder to find the Original Equipment fuel pump for your vehicle. This will show the normal operating pressure. If you have adequate fuel pressure prior to start and at idle, then you could still have a weak fuel pump that is not providing fuel while the engine is under load. We won't discuss how to test fuel flow under operating load here because it is pretty advanced stuff and too dangerous for anyone other than a trained mechanic to attempt.
If you do not have adequate fuel pressure, it does NOT mean that your fuel pump has failed. A failed fuel pressure regulator can do the same thing. If the fuel pressure regulator is returning all of the fuel to the tank without restraint, it will not allow adequate fuel pressure to be developed to run the car. (See the section in this FAQ on "How is Fuel Pressure Regulated?" for more on this.) To test this is a fairly simple matter--simply use a pair of pliers to gently mash shut the rubber hose that runs out of the fuel pressure regulator and connects to the metal line back to the gas tank. Use extrodinary care that you do not damage the fuel line. Do not do this on a metallic or hard plastic fuel line. If the fuel pressure rises to normal (or above-normal) pressures when you do this, then the regulator has failed--not the fuel pump.
If you've read this far you're certainly curious how much it would cost to replace your fuel pump if that is necessary. Use our free fuel pump lookup app to find what is available for your car, truck, or SUV!
Fuel-Pumps.Net sells Walbro Electric Fuel Pumps for the following automotive applications: Acura, Alfa Romeo, American Motors, Audi, Bentley, Bertone, BMW, Buick, Cadillac, Chevrolet, Chrysler, Citroen, Daewoo, Dodge, Eagle, Ferrari, Fiat, Ford, Geo, GMC, Holden, Honda, Hyundai, Infiniti, Isuzu, Jaguar, Jeep, Kia, Lancia, Lexus, Lincoln, Mazda, Mercedes Benz, Mercury, Merkur, Mitsubishi, Nissan, Oldsmobile, Opel, Peugeot, Pininfarina, Plymouth, Pontiac, Porsche, Range Rover, Renault, Rolls Royce, Rover, Saab, Saturn, Seat, Subaru, Suzuki, Toyota, Triumph, Vauxhall, Volkswagen, and Volvo.