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Fuel Pressure Test

Medha Godbole
A fuel pressure test is done to make sure that the fuel injection system is working properly and delivering the appropriate amount of fuel to engine. Read on to learn about the procedure of the same.
The fuel system of a car, just like a digestive system of a body, is extremely crucial for its proper functioning. A lot of how a car runs depends on the fuel pressure and the whole system. It then, becomes mandatory to check the injection system periodically.

The Procedure

For this process, you need a pressure gauge and tester. You will also need adapters for your vehicle. Poorly running cars can be a result of inadequate fuel pressure. A pump replacement will have to be considered in case the pump has completely broken down.

Step 1

Once you have gathered the tester and the other supplies required, you have to find the pressure port. For that you may have to check the manual. It is also possible that you may have to T-into the fuel line.

Step 2

Turn the car ignition on and jot down the reading. After that start the car and record the readings after running it.

Step 3

There is a possibility that the problem in the car can occur while you are driving it. In that case, you may have to take a road test for keeping a record when the car is in motion.

Step 4

Tape the gauge to the windshield and have someone check the pressure, while you drive. Compare the readings with the ones corresponding to your car in the manual.

Step 5

If the pressure is matching the specifications of the car, then there is no need to worry. If it is not, then you will either have to change the filter or need to take a look at it again.
In addition to these, check for the symptoms of a bad regulator. What you need to do is unscrew the gauge from where the fuel will come out and then hook the tester in it.
What next? What do the readings indicate? What impact does it have on parts like spark plugs? Well, here are the answers !

Fuel Pressure Scenarios

More Pressure than Required

Just as low pressure is not a good indication, excess pressure too, is not good. What will happen in such a case is, that extra pressure will force more fuel than needed through the injectors.
This will lead the engine to run rich and that in turn, will cause harm to the spark plugs, cause black smoke and surging, or a sluggish idle. The regulator will have to be checked for problems in this case.

Low Fuel Pressure

If, after the test, low pressure is found, it may be the answer to your car not performing up to the mark. Poor engine output, a choppy idle, and misfires can be a result of this condition. It can also mean that the filter is clogged. Hence, before you go for the pump replacement, be sure. Sometimes, replacing the filter will do the trick.
Finally, before you conduct the test, make sure that the pump is running. Listen closely for a distinct sound emitted by the fuel pump. Make sure that there are no bent, twisted, or pinched fuel lines. Also, see if you can do the pump relay test.
If the pump does not work, replacement could be on the cards. In case, this procedure seems to complicated, you can always go to a mechanic and get the test done.