EM276 Injector Tester can diagnose injector problems, you can use it on each injector individually to test stuck, leaking or burnt-out,which used 12V vehicle battery as power supply,it has 4 pulse modes and in the continuous working mode (mode 4) and can help you identify the injector good or not when you switch off the engine. All-Sun EM276 Profeional Injector Tester Fuel Injector 4 Pluse Modes Tester Powerful Fuel System Scan ToolAll-Sun EM276 Injector Tester Operation Instructions:Turn off the vehicle;s engineConnect Black / Red Clip to the Negative / Positive terminal of batteryConnect pulse output terminal to the fuel injectorPre the MODE SET key to select the desired pulse modePre the PULSE key, EM276 tester will output pulse to the injector, and then the pulse signal indicator will light as indicationExplanation for 4 Modes:Mode 1: the tester outputs 1 pulse, whose pulse width is about 250msMode 2: the tester outputs 50 pulse, every pulse;s pulse width is about 7msMode 3: the tester outputs 100 pulse, every pulse;s pulse width is about 3.5msMode 4: the tester outputs pulse continuously at the rate of 50 pulses per about 1450ms, every pulse;s pulse width is about 7msAll-Sun EM276 Specification:Power Supply:12V vehicle batteryOperation Environment:0 - 40, relative humidity Package Includes:1pc x Carriable Bag1pc x Instruction Manual1pc x Not Include Batteries