Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Open injector/misfire code on 2001 Dodge Durango 4.7
I have a VERY well maintained 2001 Dodge Durango 4.7 that’s throwing codes on # 2, 4, and 8. I’m attaching a photo of the codes and volt and ohm readings off each. Plugs and coil packs are new, injectors were cleaned. I’m thinking it’s the PCM (no code on 6, all evens share a harness). Is there something I’m missing? Could it be the TPS?
I don't think is related with TPS. It only works when acelerating/decelerating.
Were those voltages measured with voltmeter? I would check directly on injectors.
I don't think neither is related with injector resistance. As you can see, injectors 5 and 7 have more resistance (which is suppose less current flowing through the coil) and they are not misfiring.
What other data do you have? Fuel trims, vaccum pressure, air flow, oxygen sensor readings.
What is the performance of engine/car at wot, idle, middle range?
The volts are read of the harness at each injector, the ohms are read off the injectors themselves. The open injector/misfire at 2 and 4 are intermittent, at 8 it’s persistent, rough idle, clear misfire, and stall. The voltage on 2, 4, and 8 are the only ones outside normal range. Vacuum pressure and air flow are normal, I have not tested the O2 sensor. I wouldn’t get an O2 sensor code?
The O2 readings (and the others i mentioned) are for diagnostic purpose.
8 volts on some of the injectors has two posibilities.
The first is an injector power line issue (i would check with switch on, engine off) if 12 volts show up.
The second is that those injectors are being opened by pcm, more time than the others. Are you measuring peak to peak voltage (with scopemeter) or average voltage (with volmeter)?
Average, key on. What’s throwing me off is the normal at 6. I’m almost 100% + they share a common ground. Correct me if I’m wrong. A visual of the harness looks good.
I don't know these specific engine/circuit. But all i have seen, have a common power line and pcm is in charge of "ground" (close the circuit or open the injector).
If you have 8 volts with key on and ENGINE OFF, you have a power issue. As you said, no injectors shorted or 0 ohms (by the way, you can power those injectors with a power wire coming from battery + and extreme care not to feed control line which comes from pcm).
