Dodge Grand Caravan P2308 - Case Study Part II
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Date: 2020-08-05
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Comments and reviews: 10
Robert
After the coil warms up, the primary winding in the coil is opening making the current ramp drop to zero and arcing internally to a different turn in the coil winding. Since the driver is still turned on, and some of the winding is bypassed by the arc the current continues to increase to a much higher value than normal.
You could prove it by moving the coil to another location but better still, just replace the coil and observe that the problem no longer occurs.
For grins, you could put a voltage probe on the secondary and you would probably see two spikes, one for the glitch and another when the driver turns the coil current off.
This is the time to listen to Scotty K and put in a new coil.
Bob L
reply
After the coil warms up, the primary winding in the coil is opening making the current ramp drop to zero and arcing internally to a different turn in the coil winding. Since the driver is still turned on, and some of the winding is bypassed by the arc the current continues to increase to a much higher value than normal.
You could prove it by moving the coil to another location but better still, just replace the coil and observe that the problem no longer occurs.
For grins, you could put a voltage probe on the secondary and you would probably see two spikes, one for the glitch and another when the driver turns the coil current off.
This is the time to listen to Scotty K and put in a new coil.
Bob L
reply
theoldwizard998
Watching again, not the how long the coil is ON for when it acts up compared to how long it, or any other coil, is ON for! When it messes up, it is starting to charge (dwell) the coil coil much longer. Why it starts charging early is an unknown.
It would be interesting to look at the crankshaft position sensor pulse in relation to those 2 waveforms. One thing that will cause early charge time is adaptive dwell, which is where the PCM thinks the engine is accelerating so in order to get a full charge on the coil it starts charging the coil earlier.
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Watching again, not the how long the coil is ON for when it acts up compared to how long it, or any other coil, is ON for! When it messes up, it is starting to charge (dwell) the coil coil much longer. Why it starts charging early is an unknown.
It would be interesting to look at the crankshaft position sensor pulse in relation to those 2 waveforms. One thing that will cause early charge time is adaptive dwell, which is where the PCM thinks the engine is accelerating so in order to get a full charge on the coil it starts charging the coil earlier.
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Ron
If it was me and I didn't know for sure I would order 6 new coils and 6 new plugs. For one thing I never saw you look at the condition of the plugs. That's something I do on every misfire case. And if the vehicle is even close to needing them I replace them all. With the coils I would put 6 new on and see if the misfire goes away and the waveform looks normal. If so that's what I would stick with. If not you can always send the coils back.
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If it was me and I didn't know for sure I would order 6 new coils and 6 new plugs. For one thing I never saw you look at the condition of the plugs. That's something I do on every misfire case. And if the vehicle is even close to needing them I replace them all. With the coils I would put 6 new on and see if the misfire goes away and the waveform looks normal. If so that's what I would stick with. If not you can always send the coils back.
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Richard
Since the current limit in the PCM is set to about 15 Amps and the anomaly goes to 17 it almost has to be something in the coil. If there is a hole in the coil with carbon tracks around it we can do wild speculation.
Here's some. if there is a fault between the primary and secondary on the auto transformer where the secondary arcs back over to the primary sending HV back to the PCM it will not be a happy camper.
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Since the current limit in the PCM is set to about 15 Amps and the anomaly goes to 17 it almost has to be something in the coil. If there is a hole in the coil with carbon tracks around it we can do wild speculation.
Here's some. if there is a fault between the primary and secondary on the auto transformer where the secondary arcs back over to the primary sending HV back to the PCM it will not be a happy camper.
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Robert
Looking for some ideas. 05 Chrysler Town and country with the 3. 3. Idles nice, but won't develop any power. Starts running rough around 3500rpms, won't upshift till you let off the accelerator. If you want to go into passing gear, it's like you shifted into neutral. Exhaust glows right after manifold on 2, 4, 6 bank. Compression is good, codes P0404, P0406, & P0700
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Looking for some ideas. 05 Chrysler Town and country with the 3. 3. Idles nice, but won't develop any power. Starts running rough around 3500rpms, won't upshift till you let off the accelerator. If you want to go into passing gear, it's like you shifted into neutral. Exhaust glows right after manifold on 2, 4, 6 bank. Compression is good, codes P0404, P0406, & P0700
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Josh
Don't these engines have an issue with the valve guides on the front cylinders? If so could that be causing the miss you feel. Also if the spike your seeing was something related to a learning process wouldn't it show up on other cylinders too? Maybe there are two issues. The ignition issue and a valve issue?
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Don't these engines have an issue with the valve guides on the front cylinders? If so could that be causing the miss you feel. Also if the spike your seeing was something related to a learning process wouldn't it show up on other cylinders too? Maybe there are two issues. The ignition issue and a valve issue?
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Smitty
Wow, what a pain in the bum programming that thing! I'd have been melting down big time thinking I just made a brick, lol.
I'm going to have to check and see if the Autel I got has that capability. I don't have the Elite.
Can't wait for part III! The suspense is killing me!
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Wow, what a pain in the bum programming that thing! I'd have been melting down big time thinking I just made a brick, lol.
I'm going to have to check and see if the Autel I got has that capability. I don't have the Elite.
Can't wait for part III! The suspense is killing me!
reply
Shaun
Eric, I can't help but think that the reason tech authority wouldn't allow you to enter that PIN was because you didn't rewrite the VIN into the donor PCM first. I'd bet that would have saved you the trouble of swapping the boxes around as much as you did.
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Eric, I can't help but think that the reason tech authority wouldn't allow you to enter that PIN was because you didn't rewrite the VIN into the donor PCM first. I'd bet that would have saved you the trouble of swapping the boxes around as much as you did.
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D. R.
My main man Eric, your tenacious desire to find and confirm different possibilities of a particular problem on any given car or truck is remarkable and commendable I give you the highest respect as a man and Auto Repair Specialist. you Rock Hard Bro!
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My main man Eric, your tenacious desire to find and confirm different possibilities of a particular problem on any given car or truck is remarkable and commendable I give you the highest respect as a man and Auto Repair Specialist. you Rock Hard Bro!
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Austin
I know its an old video but if you ever run into that issue again, look at the top right it tells you the vin its reading and at the time you were having the issues it was reading the vin out of the used pcm not the car.
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I know its an old video but if you ever run into that issue again, look at the top right it tells you the vin its reading and at the time you were having the issues it was reading the vin out of the used pcm not the car.
reply
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