A Closer Look At A Coil On Plug Mis-Fire
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Date: 2020-08-05
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Comments and reviews: 10
Tony
Have had a 04 4. 7 Durango that seems to go through coil packs quite often, this will be more helpful in testing the coil packs, generally I've just used a bosch scan tool to tell me which cylinder is misfiring. At one point I just replaced all the coil packs at once to see if the vehicle would run better. It seems to run smooth most the time when driving however when driving over a hill on the highway it just doesn't have the power and starts losing speed going over the hill. If I push the pedal down to kick into a lower hearPassing gear the motor just starts to clatter really bad and then the check engine light starts flashing. I have a 98 ford v6 van, a 02 dodge van and a 2011 durango 4 banger that all have more balls than this pos 4. 7. any thoughts, it had some bad o2 sensors that I did replace a while back. There is an known issue with the gas tank vent being clogged as the gas tank will pull a vacuum if I leave the gas cap tight. Plugs where replaced 2 years ago. 220k miles. Help! Thanks, love your videos.
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Have had a 04 4. 7 Durango that seems to go through coil packs quite often, this will be more helpful in testing the coil packs, generally I've just used a bosch scan tool to tell me which cylinder is misfiring. At one point I just replaced all the coil packs at once to see if the vehicle would run better. It seems to run smooth most the time when driving however when driving over a hill on the highway it just doesn't have the power and starts losing speed going over the hill. If I push the pedal down to kick into a lower hearPassing gear the motor just starts to clatter really bad and then the check engine light starts flashing. I have a 98 ford v6 van, a 02 dodge van and a 2011 durango 4 banger that all have more balls than this pos 4. 7. any thoughts, it had some bad o2 sensors that I did replace a while back. There is an known issue with the gas tank vent being clogged as the gas tank will pull a vacuum if I leave the gas cap tight. Plugs where replaced 2 years ago. 220k miles. Help! Thanks, love your videos.
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Tony
I'm sorry, as one who holds an Electrical Engineering degree, I have a complaint.
The switch at the bottom is OPENED when you want spark. Current flows through the primary, as your waveform describes, and then the circuit is opened.
When current runs through the primary, a magnetic field is created in the coil. When that current is interrupted, the magnetic field has to go somewhere and it creates a high voltage in the secondary side. That voltage is high enough to jump the spark gap.
The equation for how coils work is as follows: V = Voltage, N=Number of turns in winding.
VpNs = VsNp
Because Vs/Vp = Ns/Np
It's the sudden stop in the flow of current that creates the voltage and ultimately current in the secondary as the B field (magnetic field for non-physics / EE types) drops.
This is why at high RPMs some coils cannot keep up as you cannot build up a sufficient B field to subsequently create the high voltage in the secondary.
reply
I'm sorry, as one who holds an Electrical Engineering degree, I have a complaint.
The switch at the bottom is OPENED when you want spark. Current flows through the primary, as your waveform describes, and then the circuit is opened.
When current runs through the primary, a magnetic field is created in the coil. When that current is interrupted, the magnetic field has to go somewhere and it creates a high voltage in the secondary side. That voltage is high enough to jump the spark gap.
The equation for how coils work is as follows: V = Voltage, N=Number of turns in winding.
VpNs = VsNp
Because Vs/Vp = Ns/Np
It's the sudden stop in the flow of current that creates the voltage and ultimately current in the secondary as the B field (magnetic field for non-physics / EE types) drops.
This is why at high RPMs some coils cannot keep up as you cannot build up a sufficient B field to subsequently create the high voltage in the secondary.
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Kevin
Wow, that was so cool and it is true that 2 heads are better than one, at least in this case. Ivan was able to fill in really well. I especially like learning about the return voltage, albeit so small returning through the ground. It reminded me of when I made pellicles at DuPont that were basically used as dust covers to etch circuits on chips. This process was done in a clean room with this solution called nitrocellulose that was only viable when the temp was between 68 & 72 degrees and the humidity between 38 and 42. The solution was dispensed on a plate of glass spinning at a certain rate which varied depending on the specific pellicle. That was in the early 90's and we were down to only being able to have sub micron particles which was the largest gap on the chip where the circuit would still function. That process may now be obsolete with the size of the chips getting smaller and smaller. Thanks for sharing.
reply
Wow, that was so cool and it is true that 2 heads are better than one, at least in this case. Ivan was able to fill in really well. I especially like learning about the return voltage, albeit so small returning through the ground. It reminded me of when I made pellicles at DuPont that were basically used as dust covers to etch circuits on chips. This process was done in a clean room with this solution called nitrocellulose that was only viable when the temp was between 68 & 72 degrees and the humidity between 38 and 42. The solution was dispensed on a plate of glass spinning at a certain rate which varied depending on the specific pellicle. That was in the early 90's and we were down to only being able to have sub micron particles which was the largest gap on the chip where the circuit would still function. That process may now be obsolete with the size of the chips getting smaller and smaller. Thanks for sharing.
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arcadeuk
On my F10 BMW M5, the coils like to fail alot. If I get a a missfire count of only 3 on any cylinder, it goes into limp-mode. When it goes into limp mode, it switches off the fuel injector to the 1 coil that is missfiring, but it also switches off all 4 cylinder on the opposite bank, for reasons I will never know? As you can imagine, driving a V8 running on only 3 of 8 cylinders in limp mode restricted to about 10% power is not at all a good experience. Anyone know why is switches off the whole opposite bank?
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On my F10 BMW M5, the coils like to fail alot. If I get a a missfire count of only 3 on any cylinder, it goes into limp-mode. When it goes into limp mode, it switches off the fuel injector to the 1 coil that is missfiring, but it also switches off all 4 cylinder on the opposite bank, for reasons I will never know? As you can imagine, driving a V8 running on only 3 of 8 cylinders in limp mode restricted to about 10% power is not at all a good experience. Anyone know why is switches off the whole opposite bank?
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spelunkerd
In a one week gap since your last video, I scrolled back to watch this classic one again. Brilliant review, even better after a few years. Many new COP systems don't give easy access to the secondary or to the switch side of the primary, so this is harder to analyze with modern designs. If you ever get a free moment, an update regarding how you investigate those systems (with the transistor inside the coil pack) would be helpful. Happy New Year, Eric!
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In a one week gap since your last video, I scrolled back to watch this classic one again. Brilliant review, even better after a few years. Many new COP systems don't give easy access to the secondary or to the switch side of the primary, so this is harder to analyze with modern designs. If you ever get a free moment, an update regarding how you investigate those systems (with the transistor inside the coil pack) would be helpful. Happy New Year, Eric!
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Douglas
Hope you make a vid on the 5. 3 trailblazer. I have one that I changed out DOD but need to disable DOD/AFM on Ecu. Maybe you have some tips? I have it temporarily disabled by unplugging vacuum sensor on brake booster but would like to get it disabled properly. And yes, they go like crazy.
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Hope you make a vid on the 5. 3 trailblazer. I have one that I changed out DOD but need to disable DOD/AFM on Ecu. Maybe you have some tips? I have it temporarily disabled by unplugging vacuum sensor on brake booster but would like to get it disabled properly. And yes, they go like crazy.
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lhoanii
I have really tried to like Ivan. Initially, he kept interrupting Eric which annoyed me. He seems a little more respectful in these later videos. There is something about Ivan that I simply don't like. Oh well, good video for c. o. p. ignition short.
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I have really tried to like Ivan. Initially, he kept interrupting Eric which annoyed me. He seems a little more respectful in these later videos. There is something about Ivan that I simply don't like. Oh well, good video for c. o. p. ignition short.
reply
trcarter80
Thanks for thoroughly exploring and explaining everything from start to finish. Most videos leave viewers with questions unanswered. Not the case hear at all. It was beneficial having two experts explain as well.
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Thanks for thoroughly exploring and explaining everything from start to finish. Most videos leave viewers with questions unanswered. Not the case hear at all. It was beneficial having two experts explain as well.
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brian
I think they're incorrect concerning the secondary circuit. It's absolutely not connected to the battery positive. It's connected to ground to complete the circuit. Can someone correct me if I'm wrong?
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I think they're incorrect concerning the secondary circuit. It's absolutely not connected to the battery positive. It's connected to ground to complete the circuit. Can someone correct me if I'm wrong?
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John
Eric, great video, lots of deep info ton follow. Thanks, if you can do it, I can watch. Special thanks to Ivan, watching you two talk through the condition was super. Thanks again.
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Eric, great video, lots of deep info ton follow. Thanks, if you can do it, I can watch. Special thanks to Ivan, watching you two talk through the condition was super. Thanks again.
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