How To Test Diesel Injectors: An Technician’s Viewpoint

Diesel fuel injectors should be serviced at regular intervals, and the process begins with an inspection of the injectors. The process of inspecting diesel injectors is more involved than the process of checking gasoline ones. For this reason, diesel injectors should always be checked by a trained technician who knows how to test diesel injectors properly.

The Two Types of Diesel Fuel Injectors

The diesel fuel injectors installed by manufacturers are all engine-specific, but all of these injectors fall into either of two categories. The injectors on Ford 7.3L, Chevy/GMC 6.6L, Detroit Diesel, Cat and Dodge/Cummins engines are all either common rail injectors. Testing each of these types of injectors requires a different process.

How To Test Common Rail Diesel Injectors

Common rail diesel fuel injectors are newer injectors, and they’re finely tuned by computer. In order to test these injectors, a diesel service center needs a computerized test bench that operates the injector.

When you bring a vehicle with common rail diesel injectors to J&S Diesel, we individually connect each injector to our test bench. The bench simulates real-world driving conditions, and it puts the injector through a number of checks. The process includes a high-pressure nozzle test, control valve leak test, injector start behavioral test, full-load quantity test and idle speed adjustment tuning, among other checks.

Based on the results from this computerized test, our technicians can accurately assess the condition of your vehicle’s diesel injectors and pinpoint any issues with them. Being precise in the testing allows us to repair only what must be addressed and keep the total cost of your diesel injector service lower.

How To Test Manual Diesel Injectors

Manual diesel fuel injectors tend to be on older engines, and these injectors must be inspected by hand. Because this is a manual process that depends upon the knowledge of the technician who’s performing the inspection, it should be done by someone who’s highly trained and experienced.

During a manual fuel injector inspection, one of J&S Diesel’s technicians physically disassembles each injector so that it can be thoroughly checked. The injector is then put through a series of checkers, including tests for opening pressure, spray pattern, nozzle chatter and leaks.

After the checks are complete, any malfunctioning parts are replaced and the injector is reassembled. All seals and washers are replaced with new ones during reassembly.