Injectors are among the most important components of a diesel-powered vehicle. Bad injectors can make a vehicle decrease in power, accelerate or cause it to misfire or smoke. Checking for bad injectors yourself will save you a trip to a mechanic and the mechanic's fee.
Let the vehicle's engine idle until it warms up. The engine needs to run during the project.
Check the operating temperature of each cylinder using a digital pyrometer. A cylinder's operating temperature reading that is lower than the rest indicates that cylinder is faulty or weak.
Listen for a clicking noise from the injector. Place a long-shank screwdriver directly onto the injector, and hold the screwdriver handle up to your ear. If you cannot hear a clicking noise, then the injector is probably faulty or clogged.
Measure the resistance across the injector's terminals with a digital voltage OHM meter. If the resistance is not within your vehicle's specification, then the injector needs to be replaced. The specification can be found in your vehicle's manual.