Example #7 - Current Controlled Driver
The known-good current controlled type waveform in Fig. Fig 1 is from a GM 2.0L TBI VIN [1]. With the lab scope set at 2 amps per division, notice that this system peaks at 4 amps and holds at 1 amp.
The next waveform is from the same type of engine, except that it shows a faulty injector. See Fig 2. Notice that the current went to almost 5 amps and stayed at 1 amp during the hold pattern. Excessive amounts of current flow from bad injectors are a common source of intermittent computer shutdown. Using a current waveform pattern is the most accurate method of pinpointing this problem.
