2 sparkplug system
2 sparkplug system
I changed the plugs in my 2005 hemi on Saturday and I started thinking About how the system works. Correct me if I'm wrong but I understand that the 2nd plug fires on the powerstroke. With that in mind, would one notice if the 2nd plug wasn't firing? Would it throw up a code?
Just wondering because I question how well I got some of the wires back on.
Thanks
Just wondering because I question how well I got some of the wires back on.
Thanks
So are both plugs responsible for producing power, I understood that the second plug only fired to burn any unburned fuel... basically for emission control. That is why I questioned whether you would notice it. If the second plug wasn't firing and the first plug DID it would still run without a miss... right??? Or does the second plug fire early enough on the power stroke that you would be able to feel it if it wasn't hitting?
The reason I ask is, after changing the first two plugs the little rubber boot in my spark plug socket vanished, not sure where it went, but it disappeared, I know which cylinder it would be on. I checked the plug that has only the wire (not the coil) and it is ok. I would have checked the coil but I didn't have any tools with me at the time and now its late and I don't feel like going out. I would think that if the little rubber "thingy" was still on one of the sparkplugs, that there would be no what that the plug wire would even come close to going back on.
My truck is running really smooth (noticeably better than before the plug change) but I also cleaned the throttle body while I was in there. It wasn't really dirty but not clean either.
Sorry 'bout the ramble.
The reason I ask is, after changing the first two plugs the little rubber boot in my spark plug socket vanished, not sure where it went, but it disappeared, I know which cylinder it would be on. I checked the plug that has only the wire (not the coil) and it is ok. I would have checked the coil but I didn't have any tools with me at the time and now its late and I don't feel like going out. I would think that if the little rubber "thingy" was still on one of the sparkplugs, that there would be no what that the plug wire would even come close to going back on.
My truck is running really smooth (noticeably better than before the plug change) but I also cleaned the throttle body while I was in there. It wasn't really dirty but not clean either.
Sorry 'bout the ramble.
Last edited by svkb; May 3, 2010 at 12:17 AM.
My gut feeling is they both fire too help with fuel burn, i was told that the higher octane fuel is also a slower burning fuel. which is why we have two plugs. That and the hemi cylinder is designed for that type of burn. It's why you would detonate with a 87 or less fuel. it simply burns too quick.That said I believe they fire at the same time.
Champion
Joined: Nov 2005
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From: North Eastern England
This is what I got from this link about Hemi engines.
“The extra plug fires during the power stroke to more fully burn the hydrocarbons. ... the second ignition allows additional power in the down stroke while lowering the need for restrictive catalyst plates in the converter. This increases breathing, adding to horsepower output as well.
“In the 1980s Japanese manufacturers reduced unburned hydrocarbons by placing spark plugs either in the exhaust pipe (which fired with every piston ignition) or in the exhaust manifold (which fired each time their corresponding cylinder fired). Chrysler morphed this idea to include dual fired plugs on each cylinder, which allows the firing to take place closer to top dead center, and then again when the piston is on the back side of the power stroke.
This [also reduces] NOx and O3 (ozone) emissions. Full combustion results in heat, water, and carbon dioxide. While a small amount of NOx emissions are produced, they are only significant during incomplete or partial combustion, due to the lack of available oxygen, high temperatures, and various chemical reactions. That's why catalytic converters have been standard on cars for the past 3 decades. The extra set of spark plugs on the HEMI and on previous engines are designed to reduce emissions before a catalyst is needed. They add some horsepower, but not very much. The only exception to this rule is on top-fuel dragsters that almost literally 'pour' gas down the venturis. A single plug can't burn that much gas, regardless of the ignition’s power output.”
Hmmmmm.....are we alowed to say "powerstroke" on a Dodge fprum ??? lol
Al.
“The extra plug fires during the power stroke to more fully burn the hydrocarbons. ... the second ignition allows additional power in the down stroke while lowering the need for restrictive catalyst plates in the converter. This increases breathing, adding to horsepower output as well.
“In the 1980s Japanese manufacturers reduced unburned hydrocarbons by placing spark plugs either in the exhaust pipe (which fired with every piston ignition) or in the exhaust manifold (which fired each time their corresponding cylinder fired). Chrysler morphed this idea to include dual fired plugs on each cylinder, which allows the firing to take place closer to top dead center, and then again when the piston is on the back side of the power stroke.
This [also reduces] NOx and O3 (ozone) emissions. Full combustion results in heat, water, and carbon dioxide. While a small amount of NOx emissions are produced, they are only significant during incomplete or partial combustion, due to the lack of available oxygen, high temperatures, and various chemical reactions. That's why catalytic converters have been standard on cars for the past 3 decades. The extra set of spark plugs on the HEMI and on previous engines are designed to reduce emissions before a catalyst is needed. They add some horsepower, but not very much. The only exception to this rule is on top-fuel dragsters that almost literally 'pour' gas down the venturis. A single plug can't burn that much gas, regardless of the ignition’s power output.”
Hmmmmm.....are we alowed to say "powerstroke" on a Dodge fprum ??? lol
Al.
Last edited by abarmby; May 3, 2010 at 03:53 AM.
This is what I got from this link about Hemi engines.
“The extra plug fires during the power stroke to more fully burn the hydrocarbons. ... the second ignition allows additional power in the down stroke while lowering the need for restrictive catalyst plates in the converter. This increases breathing, adding to horsepower output as well.
“In the 1980s Japanese manufacturers reduced unburned hydrocarbons by placing spark plugs either in the exhaust pipe (which fired with every piston ignition) or in the exhaust manifold (which fired each time their corresponding cylinder fired). Chrysler morphed this idea to include dual fired plugs on each cylinder, which allows the firing to take place closer to top dead center, and then again when the piston is on the back side of the power stroke.
This [also reduces] NOx and O3 (ozone) emissions. Full combustion results in heat, water, and carbon dioxide. While a small amount of NOx emissions are produced, they are only significant during incomplete or partial combustion, due to the lack of available oxygen, high temperatures, and various chemical reactions. That's why catalytic converters have been standard on cars for the past 3 decades. The extra set of spark plugs on the HEMI and on previous engines are designed to reduce emissions before a catalyst is needed. They add some horsepower, but not very much. The only exception to this rule is on top-fuel dragsters that almost literally 'pour' gas down the venturis. A single plug can't burn that much gas, regardless of the ignition’s power output.”
Hmmmmm.....are we alowed to say "powerstroke" on a Dodge fprum ??? lol
Al.
“The extra plug fires during the power stroke to more fully burn the hydrocarbons. ... the second ignition allows additional power in the down stroke while lowering the need for restrictive catalyst plates in the converter. This increases breathing, adding to horsepower output as well.
“In the 1980s Japanese manufacturers reduced unburned hydrocarbons by placing spark plugs either in the exhaust pipe (which fired with every piston ignition) or in the exhaust manifold (which fired each time their corresponding cylinder fired). Chrysler morphed this idea to include dual fired plugs on each cylinder, which allows the firing to take place closer to top dead center, and then again when the piston is on the back side of the power stroke.
This [also reduces] NOx and O3 (ozone) emissions. Full combustion results in heat, water, and carbon dioxide. While a small amount of NOx emissions are produced, they are only significant during incomplete or partial combustion, due to the lack of available oxygen, high temperatures, and various chemical reactions. That's why catalytic converters have been standard on cars for the past 3 decades. The extra set of spark plugs on the HEMI and on previous engines are designed to reduce emissions before a catalyst is needed. They add some horsepower, but not very much. The only exception to this rule is on top-fuel dragsters that almost literally 'pour' gas down the venturis. A single plug can't burn that much gas, regardless of the ignition’s power output.”
Hmmmmm.....are we alowed to say "powerstroke" on a Dodge fprum ??? lol
Al.
I read that same article. So do we think that the extra plug fires early enough that if it was not functional on one cylinder, it would feel like a slight miss perhaps??