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This, coupled with the inherent resistance of the driver's transistor, impedes the current flow even more. So, what is a known good value for a Fig. 4 . Note that if just one injector has a resistance problem and partially shorts, the entire parallel bank that it belongs to will draw more current. The waveform pattern in Fig. Fig. 5 indicates this type of problem with too much current flow. This is on other bank of injectors of the same vehicle; the even side. Notice the Lab Scope is set on a one amp per division scale. As you can see, the current is at an unacceptable 2.5 amps. It is easy to find out which individual injector is at fault. All you need to do is inductively clamp onto each individual injector and compare Fig. 6 . Notice that it limits current flow to 750 milliamps. The waveform shown in Fig. Fig. 7 illustrates the problem injector we found. This waveform indicates an unacceptable current draw of just over one amp as compared to the 750 milliamp draw of the known-good injector. A subsequent check with a DVOM found 8.2 ohms, which is
Fig. 4: Injector Bank w/Normal Current Flow - Current Pattern
Fig. 5: Injector Bank w/Excessive Current Flow - Current Pattern
Fig. 6: Single Injector w/Normal Current Flow - Current Pattern
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