How to

How to check diesel injector spray pattern

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Many cars have fuel injectors installed in the engine at an angle, while others are placed vertically. To ensure that the diesel fuel injector spray pattern is normal, you may need to test the injector. 

Find out how to do just that with some help from the experts at Delphi. Watch the video and get a refresher on: 

  • How to test the fuel injector spray pattern 
  • Why you’ll need a dedicated common rail injector tester in the workshop 
  • A common misdiagnosis of a diesel injector which isn’t necessarily faulty.
Diesel Fuel Systems How to Technicians

What should fuel injector spray look like? 

When it’s in the testing machine with settings adjusted for our ease of visibility, a working fuel injector spray should be pumping out a clear-coloured, fine spray – a light misting potentially. 

Does injector spray pattern matter? 

The spray pattern inside a fuel injector is important. The spray needs to be directed into the combustion chamber at the correct angle and atomisation shape. Any issues with this could cause engine misfire. 

What causes distorted spray pattern in injector? 

A dirty or clogged diesel injector is a common cause of the spray pattern becoming distorted. The wrong mix of air and fuel could also be affecting the path of the spray.


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