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Essay On Diagnosing Fuel Systems In Cars

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Guide to Diagnosing Fuel Systems in Cars

In this guide to diagnosing fuel systems we'll discover why this is such an important skill to master. If you own an automobile long enough chances are you'll experience an engine that cranks around, but won't start. When this situation occurs the root cause lies within two complex automotive systems.

You need to have a powerful spark to start an internal combustion engine. However, that spark becomes completely useless unless a fuel charge exists to ignite. When an engine turns over normally, but refuses to start it's time to dig into these two possibilities. Here we'll explore the fuel side of the equation.

Note that a vehicle specific auto repair manuals remain available for your convenience
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This makes it hard to hear the electric pump running. With that said, if you remove the fuel cap and stick your ear near the fuel filler tube you'll hear the pump run. Of course, you'll need a friend to cycle the key on and off while you listen for the buzz.

Taking a Fuel Pressure Reading

If we hear the fuel pump running, it still doesn't mean that gas reaches the engine. In fact, modern fuel injection requires 35 to 65 psi of pressure to operate properly. Most vehicle manufacturers help us out by providing a quick check Schrader valve where you can attach a pressure tester to obtain an accurate reading.

This tester becomes important for properly diagnosing fuel systems. Fortunately, you can find this [[important diagnostic tool]] in the $25 range. Here's how you accomplish an accurate fuel pressure reading. After we attach the test gauge to the fuel rail we then cycle the key on and off to run the pump. Remember that just because the pump runs doesn't mean that it's actually producing any pressure.

In fact, if we have a reading on a fuel injected automobile below 40 psi it's time to check the condition of the fuel filter. In a situation where the old filter has a lot of time and miles on it, it's a good idea to replace it and then retest the pressure at the rail. Remember to check your auto repair manual for the proper specifications of fuel pressure for your specific automobile. This becomes important on some [[Mercedes-Benz automobiles]] that
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