Ok so I was getting a misfire code on cyl 7 on my 05 hemi, I was getting intermittent stalling but truck seemed to run normal, I changed plugs (champion coppers) and wires (taylor shorties) and replaced cyl 7 coil pack, now it's missing really bad no power and throws cyl 1 and 7 misfire codes, I unplugged the harness and I'm getting .2 volts to 1 & 7, and about 3.6 volts to 3,5,2,4,6 & 8, I looked at the wiring and I'm not seeing any cut or burnt wires, could it be the coil drivers in the ram, I'm not sure what to do next, I really don't want to go to the stealership
Misfire HELP
Ohemi
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Ok so I was getting a misfire code on cyl 7 on my 05 hemi, I was getting intermittent stalling but truck seemed to run normal, I changed plugs (champion coppers) and wires (taylor shorties) and replaced cyl 7 coil pack, now it's missing really bad no power and throws cyl 1 and 7 misfire codes, I unplugged the harness and I'm getting .2 volts to 1 & 7, and about 3.6 volts to 3,5,2,4,6 & 8, I looked at the wiring and I'm not seeing any cut or burnt wires, could it be the coil drivers in the ram, I'm not sure what to do next, I really don't want to go to the stealership
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The coils and injectors are powered from the ASD relay and actually seperate in the harness behind the ac pump. The source is 12vdc. The pcm then grounds the individual coils and injectors at specific times based on the crank and cam sensors. When the engine is running the crank sensor provides a "sense" to the pcm that the crank is turning and keeps the ASD relay closed providing 12vdc to coils, injectors and fuel pump. After about 3-5 seconds if the pcm doesn't recieve the rotating sense it opens the ASD relay removing the 12vdc. You can test this by turning on the ignition switch and listen for the fuel pump. It will run and then quit after the 3-5 seconds. So measuring the coil voltage with the ignition turned on won't give you a reading. With the engine running you can unplug the suspected coil and should have 12vdc at the plug. You can move the coils getting codes to other cylinder one at a time and see if the code follows the coil. If you just installed the shorties, try putting the original wires back on. Some trucks have issues using them. Good luck.
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Disconnect the electrical plug at the coil and measure at the electrical plug with the engine running or have someone turn on the key while you measure. If no 12vdc, then measure one that is working properly. If bad you will need to follow the wire back to the ASD relay. It's frustrating but pretty straight forward troubleshooting.
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Should be 12v. Measure the ASD relay.
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On the coils unplug the harness one at a time and check for 12v. Don't ground the 12v wire as you will blow a fuse. The ASD you can swap it it with another relay.. pull the relay out and check for 12v on on the contact pins. If you have a relay that the cover comes off it makes it easy.
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Take the red wire on your meter touch the connector plug wire. The black wire on your meter goes to ground. Each connection plug has two wires. One of the wires is the same color on all of the plugs. This is your 12vdc source wire. The wire that is unique to each plug is the wire that goes to the pcm.
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That or the negative post on the battery.
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Greg. :thumb::thumb:
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