Pressure Drop Test

The pressure drop method requires the use of a fuel pressure gauge and an injector pulse timer available from specialty tool vendors. Generally speaking, this test can be performed without removing the injector from the engine. By energizing the injector for a fixed pulse width and observing the pressure drop on the fuel system, the relative fuel flow can be compared for each injector. If all injectors exhibit a consistent pressure drop, it follows that all injectors are flowing the same volume of fuel. There are three shortcomings with this type of test which limit its usefulness, they are:

• Actual injector flow volume can not be determined, only relative flow

• Spray pattern cannot be observed during this test

• There are no specifications for the pressure drop test.

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

Don't pay hundreds of dollars to find out what is wrong with your car. This book is dedicated to helping the do it yourself home and independent technician understand and use OBD-II technology to diagnose and repair their own vehicles.

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