You hop in your vehicle, turn the key, and you hear the motor turning but it doesn't quite start. What gives? Well, you know the starter is good because the motor is cranking so it's either fuel, spark, or compression. Now, with modern vehicles spark isn't much of an issue because coil on plug systems are much more reliable than the older distributor based ignition system. Compression should also be a non-issue unless you overheated the motor and blew a head gasket. This leaves us with fuel as a probable culprit. The fuel system has many components including the fuel pump, fuel injectors, fuel filter, fuel lines, and wiring. Instead of rushing into a fuel pump replacement, make sure every other part of the system is working properly. This will help you avoid a costly, time consuming, and unnecessary repair.

The best way to begin a system diagnosis is by doing a fuel pressure test
. If the pressure is good then we know the fuel pump is good and everything leading up to the fuel rail, thus helping us pinpoint the problem. By conducting a pressure test, what we are really doing is testing the pump. There are a number of ways to test the fuel pump depending on what kind of vehicle you have.

1. If you don't have a fuel pressure tester go ahead and purchase one from your local auto parts store.
2. Unscrew the cap covering the Shrader valve
3. Plug in the fuel pressure tester
4. Crank the vehicle
5. Look at the reading on the fuel pressure tester. You will typically want somewhere around 40psi. This is extremely general and you should, by all means, find the specification by looking in your factory service manual or searching for that information online.
6. If there is no fuel pressure, try swapping the fuel pump relay in the fuse box with a relay similar to it. Does the vehicle start now? Then that's all there was to it, a simple relay.
7. Is there some pressure but not much? Try replacing your fuel filter as it could be clogged. This could save you hundreds of dollars!
8. If the previous two suggestions don't work then it's time to get a fuel pump. Now if your vehicle doesn't have a Shrader valve you will have to hook your fuel pressure tester in line with the rail.

Follow the steps below to do this:

1. This is the most important step here. Relieve fuel system pressure! Open the fuse box and remove the pump relay. Try starting your car for about 5 seconds. Do this a couple times. What you have done here is effectively relieved the pressure out of the fuel system. You are doing this because you will be removing a line and if you didn't relieve the fuel pressure, well, let's just say it wouldn't be pretty.
2. Disconnect the fuel line at the "feed" part of the fuel rail. How do you know which is feed and which is return? Follow the fuel filter. The fuel filter side will always be the feed side. Go ahead and plug in your fuel pressure tester with the attachments that came with it and tighten everything down securely.
3. Plug in the fuel pump relay
4. Try starting the vehicle. Look at the pressure reading on the fuel pressure gauge

Is there no pressure? Try swapping the fuel pump relay with another one similar to it (i.e.: A/C relay)

Is the pressure low? This could be a clogged fuel filter. Go ahead and replace it because this could very well be the culprit, and if it is, you have saved yourself hundreds of dollars if you thought it was the fuel pump.
5. Still no success with the previous two recommendations? You are going to have to dish out some money and replace the fuel pump.

That's all there is to it. If you fixed your vehicle great; if you have found that it is in need of a pump, you will find that it is a bit more involved, but still manageable. Look out for one of our articles regarding fuel pump replacement and you'll have your vehicle fixed in no time.

Max Rossi writes for AutoBlock [] - Free online high-definition automotive videos, high-quality car photography, user community, forums and galleries.
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Article Source:
How can you tell if it is a fuel pump problem or bad plugs?


Remove Your Air Filter, If You See A Liquid Squirt or bubble up, Or smell gas, then its the plugs


What is the problem? Why are you limiting the problem to those 2 areas of concern?


If it is the electronic fuel pump that is the problem you will not hear the fuel pump humm as you turn the key in the ignition. Replace the fuel pump which is located inside the gas tank.


after you have replace the pump and it doesn't humm what else could be the problem

the fuel pump could still humm but it could be weak. there is a pressure valve on the fuel line behind the intake. put a pressure tester on it. if it is over 45 lbs. then your fuel pump is ok.
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Fuel Pump Repair Topics:
Fuel System Diagnosis
By Max Rossi
Let's begin by having you look at your fuel rail. The rail is the long metallic object that distributes fuel to the injectors. If the vehicle has a 4 cylinder then there will only be one rail, a 6 or 8 cylinders, 2 rails. Now look to see if the fuel rail has a Shrader valve. A Shrader valve is similar to a valve stem on a tire but its only purpose is for you to check fuel pressure. Most of the time you will find a cap covering the valve to inhibit dust and dirt from getting in. So if your vehicle has a Shrader valve, follow the steps below. If not, skip this section and read on.
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