Exhaust questions
#21
08-25-2007, 02:55 AM
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RE: Exhaust questions
As for the post-cat sensors not effecting fuel/air ratio, I will quote the 2001 Dakota manual:
Upstream Sensor - Engine Equipped With 2 Sensors:
The upstream sensor (1/1) provides an input voltage to the PCM. The input tells the PCM the oxygen content of the exhaust gas. The PCM uses this information to fine tune fuel delivery to maintain the correct oxygen content at the downstream oxygen sensor. The PCM will change the air/fuel ratio until the upstream sensor inputs a voltage that the PCM has determined will make the downstream sensor output (oxygen content) correct.
The upstream oxygen sensor also provides an input to determine catalytic convertor efficiency.
Downstream Sensor - Engine Equipped With 2 Sensors:
The downstream oxygen sensor (1/2) is also used to determine the correct air-fuel ratio. As the oxygen content changes at the downstream sensor, the PCM calculates how much air-fuel ratio change is required. The PCM then looks at the upstream oxygen sensor voltage and changes fuel delivery until the upstream sensor voltage changes enough to correct the downstream sensor voltage (oxygen content).
The downstream oxygen sensor also provides an input to determine catalytic convertor efficiency.
Upstream Sensors - Engine Equipped With 4 Sensors:
Two upstream sensors are used (1/1 and 2/1). The 1/1 sensor is the first sensor to receive exhaust gases from the #1 cylinder. They provide an input voltage to the PCM. The input tells the PCM the oxygen content of the exhaust gas. The PCM uses this information to fine tune fuel delivery to maintain the correct oxygen content at the downstream oxygen sensors. The PCM will change the air/fuel ratio until the upstream sensors input a voltage that the PCM has determined will make the downstream sensors output (oxygen content) correct.
The upstream oxygen sensors also provide an input to determine mini-catalyst efficiency. Main catalytic convertor efficiency is not calculated with this package.
Downstream Sensors - Engine Equipped With 4 Sensors:
Two downstream sensors are used (1/2 and 2/2). The downstream sensors are used to determine the correct air-fuel ratio. As the oxygen content changes at the downstream sensor, the PCM calculates how much air-fuel ratio change is required. The PCM then looks at the upstream oxygen sensor voltage, and changes fuel delivery until the upstream sensor voltage changes enough to correct the downstream sensor voltage (oxygen content).
The downstream oxygen sensors also provide an input to determine mini-catalyst efficiency. Main catalytic convertor efficiency is not calculated with this package.
Engines equipped with either a downstream sensor(s), or a post-catalytic sensor, will monitor catalytic convertor efficiency. If efficiency is below emission standards, the Malfunction Indicator Lamp (MIL) will be illuminated and a Diagnostic Trouble Code (DTC) will be set. Refer to Monitored Systems in Emission Control Systems for additional information.
Take this as you will.
#22
08-25-2007, 07:43 AM
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#23
08-25-2007, 11:12 AM
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RE: Exhaust questions
hmm so by this all the guys that zip tied their o2s to the frame are running rich?
but yes i do have other problems, but i figured step one was to eliminate the exhaust blockage, then two work from there. my exhaust work is done atm, no cat, no muffler, 2.5 pipe. ive got new plugs, wires, distributor cap, and rotar. I will get to the tune up when ever the weather clears. my truck already runs 100% better. in the future I will have to throw a new muffler on
, i dont quite like the sound at high rpms right now.
I thank everyone for their input, much appriciated.
but yes i do have other problems, but i figured step one was to eliminate the exhaust blockage, then two work from there. my exhaust work is done atm, no cat, no muffler, 2.5 pipe. ive got new plugs, wires, distributor cap, and rotar. I will get to the tune up when ever the weather clears. my truck already runs 100% better. in the future I will have to throw a new muffler on
, i dont quite like the sound at high rpms right now. I thank everyone for their input, much appriciated.
#24
08-25-2007, 12:50 PM
RE: Exhaust questions
ORIGINAL: dodgerules86
As for the post-cat sensors not effecting fuel/air ratio, I will quote the 2001 Dakota manual:
[/align][align=left]Take this as you will.[/align]
As for the post-cat sensors not effecting fuel/air ratio, I will quote the 2001 Dakota manual:
[align=left]Upstream Sensor - Engine Equipped With 2 Sensors: The upstream sensor (1/1) provides an input voltage to the PCM. The input tells the PCM the oxygen content of the exhaust gas. The PCM uses this information to fine tune fuel delivery to maintain the correct oxygen content at the downstream oxygen sensor. The PCM will change the air/fuel ratio until the upstream sensor inputs a voltage that the PCM has determined will make the downstream sensor output (oxygen content) correct.[/align][align=left]The upstream oxygen sensor also provides an input to determine catalytic convertor efficiency.[/align][align=left][/align][align=left]Downstream Sensor - Engine Equipped With 2 Sensors: The downstream oxygen sensor (1/2) is also used to determine the correct air-fuel ratio. As the oxygen content changes at the downstream sensor, the PCM calculates how much air-fuel ratio change is required. The PCM then looks at the upstream oxygen sensor voltage and changes fuel delivery until the upstream sensor voltage changes enough to correct the downstream sensor voltage (oxygen content).[/align][align=left]The downstream oxygen sensor also provides an input to determine catalytic convertor efficiency.[/align][align=left][/align][align=left]Upstream Sensors - Engine Equipped With 4 Sensors: Two upstream sensors are used (1/1 and 2/1). The 1/1 sensor is the first sensor to receive exhaust gases from the #1 cylinder. They provide an input voltage to the PCM. The input tells the PCM the oxygen content of the exhaust gas. The PCM uses this information to fine tune fuel delivery to maintain the correct oxygen content at the downstream oxygen sensors. The PCM will change the air/fuel ratio until the upstream sensors input a voltage that the PCM has determined will make the downstream sensors output (oxygen content) correct.[/align][align=left]The upstream oxygen sensors also provide an input to determine mini-catalyst efficiency. Main catalytic convertor efficiency is not calculated with this package.[/align][align=left][/align][align=left]Downstream Sensors - Engine Equipped With 4 Sensors: Two downstream sensors are used (1/2 and 2/2). The downstream sensors are used to determine the correct air-fuel ratio. As the oxygen content changes at the downstream sensor, the PCM calculates how much air-fuel ratio change is required. The PCM then looks at the upstream oxygen sensor voltage, and changes fuel delivery until the upstream sensor voltage changes enough to correct the downstream sensor voltage (oxygen content).[/align][align=left]The downstream oxygen sensors also provide an input to determine mini-catalyst efficiency. Main catalytic convertor efficiency is not calculated with this package.[/align][align=left]Engines equipped with either a downstream sensor(s), or a post-catalytic sensor, will monitor catalytic convertor efficiency. If efficiency is below emission standards, the Malfunction Indicator Lamp (MIL) will be illuminated and a Diagnostic Trouble Code (DTC) will be set. Refer to Monitored Systems in Emission Control Systems for additional information.
Ive seen it done, ive done it. Do what you want, all im saying is that its better to ziptie it instead of using sims, and running no cat wil give you better flow, or hell run a highflow if your worried about codes and o2s..
#25
08-25-2007, 04:26 PM
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RE: Exhaust questions
ORIGINAL: User2006
have you ever installed a a/f guage to any of the O2s? if you hook it up to the 1/2 the reading will be Backwords, if you hook it up to the 1/1 it will show you the correct a/f. If you read the manul quote it says it in there. the 1/1 figures out the correct air to fuel and send it to the pcm and the pcm will try to keep it at the correct level, who cars about what the levels are after the cat? If you want correct reading look at 1/1.. also since the pcm tries to compensate for both 02 oxgen levels zipting it to the fram would tell the pcm nothing but that your cat is working 100% correct. Isnt that what cats are for? you want the least amount of deadly fumes to come out your exhuast. Meaning deleteing the cat your exhuast will smell more rich only becuase the cat isnt cleaning it.
Ive seen it done, ive done it. Do what you want, all im saying is that its better to ziptie it instead of using sims, and running no cat wil give you better flow, or hell run a highflow if your worried about codes and o2s..
have you ever installed a a/f guage to any of the O2s? if you hook it up to the 1/2 the reading will be Backwords, if you hook it up to the 1/1 it will show you the correct a/f. If you read the manul quote it says it in there. the 1/1 figures out the correct air to fuel and send it to the pcm and the pcm will try to keep it at the correct level, who cars about what the levels are after the cat? If you want correct reading look at 1/1.. also since the pcm tries to compensate for both 02 oxgen levels zipting it to the fram would tell the pcm nothing but that your cat is working 100% correct. Isnt that what cats are for? you want the least amount of deadly fumes to come out your exhuast. Meaning deleteing the cat your exhuast will smell more rich only becuase the cat isnt cleaning it.
Ive seen it done, ive done it. Do what you want, all im saying is that its better to ziptie it instead of using sims, and running no cat wil give you better flow, or hell run a highflow if your worried about codes and o2s..
Downstream Sensor - Engine Equipped With 2 Sensors: The downstream oxygen sensor (1/2) is also used to determine the correct air-fuel ratio.
Downstream Sensors - Engine Equipped With 4 Sensors: Two downstream sensors are used (1/2 and 2/2). The downstream sensors are used to determine the correct air-fuel ratio.
The other function is new for 1996 model-year vehicles equipped with JTEC PCMs. While the upstream O2S input is used to maintain the 14.7:1 Air/Fuel (A/F), variations in engines, exhaust systems and catalytic converters may cause this ratio to be less than ideal for a particular catalyst and engine. To help maintain the catalyst operating at maximum efficiency, the PCM will fine tune the A/F ratio entering the catalyst, based upon the oxygen content leaving the catalyst. This is accomplished by modifying the upstream O2S voltage goal. In the past, this goal was a preprogrammed fixed value, based on where the catalyst was believed to operate most efficiently. With the new downstream O2S fuel control, the upstream O2 goal is moved up and down, within the window of operation of the O2 Sensor. If the oxygen content leaving the catalyst is too lean (excess oxygen), the PCM will move the upstream O2 goal up, which will increase fuel in the mixture, causing less oxygen to be left over. Conversely, if the oxygen content leaving the catalyst is too rich (not enough oxygen), the PCM will move the upstream O2 goal down, which will remove fuel from the mixture, causing more oxygen to be left over.
This function only occurs during cruise mode operation. Currently, this function is not being used on 5.9L heavy-duty engines with automatic transmissions. The 5.9L heavy-duty vehicles do not have downstream O2 Sensors
As for answering your questions, no I haven't installed an air/fuel gauge, and have no intent on doing so, so long as I have a V6 in my truck. And yes, the purpose of cats are to clean the exhaust to meet emissions standards.
Personally, I don't care. If I had went through more than 1 cat, I would just killthe catand go from there. If my mileage started to suffer or it threw codes, I'd "work it out."
But yes, if your worried, or "have to have a cat" due to ****'s running your state, I'd go for a high-flow. But whatever you do, don't get a $300+ from-the-dealership cat.
#26
08-26-2007, 12:25 AM
RE: Exhaust questions
ORIGINAL: dodgerules86
Haha... just hold on to your pants, User2006
That is taken from, "3.9L/5.2L/5.9L Magnum Fuel Injection," published by Chrysler.
As for answering your questions, no I haven't installed an air/fuel gauge, and have no intent on doing so, so long as I have a V6 in my truck. And yes, the purpose of cats are to clean the exhaust to meet emissions standards.
Personally, I don't care. If I had went through more than 1 cat, I would just killthe catand go from there. If my mileage started to suffer or it threw codes, I'd "work it out."
But yes, if your worried, or "have to have a cat" due to ****'s running your state, I'd go for a high-flow. But whatever you do, don't get a $300+ from-the-dealership cat.
ORIGINAL: User2006
have you ever installed a a/f guage to any of the O2s? if you hook it up to the 1/2 the reading will be Backwords, if you hook it up to the 1/1 it will show you the correct a/f. If you read the manul quote it says it in there. the 1/1 figures out the correct air to fuel and send it to the pcm and the pcm will try to keep it at the correct level, who cars about what the levels are after the cat? If you want correct reading look at 1/1.. also since the pcm tries to compensate for both 02 oxgen levels zipting it to the fram would tell the pcm nothing but that your cat is working 100% correct. Isnt that what cats are for? you want the least amount of deadly fumes to come out your exhuast. Meaning deleteing the cat your exhuast will smell more rich only becuase the cat isnt cleaning it.
Ive seen it done, ive done it. Do what you want, all im saying is that its better to ziptie it instead of using sims, and running no cat wil give you better flow, or hell run a highflow if your worried about codes and o2s..
have you ever installed a a/f guage to any of the O2s? if you hook it up to the 1/2 the reading will be Backwords, if you hook it up to the 1/1 it will show you the correct a/f. If you read the manul quote it says it in there. the 1/1 figures out the correct air to fuel and send it to the pcm and the pcm will try to keep it at the correct level, who cars about what the levels are after the cat? If you want correct reading look at 1/1.. also since the pcm tries to compensate for both 02 oxgen levels zipting it to the fram would tell the pcm nothing but that your cat is working 100% correct. Isnt that what cats are for? you want the least amount of deadly fumes to come out your exhuast. Meaning deleteing the cat your exhuast will smell more rich only becuase the cat isnt cleaning it.
Ive seen it done, ive done it. Do what you want, all im saying is that its better to ziptie it instead of using sims, and running no cat wil give you better flow, or hell run a highflow if your worried about codes and o2s..
Downstream Sensor - Engine Equipped With 2 Sensors: The downstream oxygen sensor (1/2) is also used to determine the correct air-fuel ratio.
Downstream Sensors - Engine Equipped With 4 Sensors: Two downstream sensors are used (1/2 and 2/2). The downstream sensors are used to determine the correct air-fuel ratio.
[align=left]The other function is new for 1996 model-year vehicles equipped with JTEC PCMs. While the upstream O2S input is used to maintain the 14.7:1 Air/Fuel (A/F), variations in engines, exhaust systems and catalytic converters may cause this ratio to be less than ideal for a particular catalyst and engine. To help maintain the catalyst operating at maximum efficiency, the PCM will fine tune the A/F ratio entering the catalyst, based upon the oxygen content leaving the catalyst. This is accomplished by modifying the upstream O2S voltage goal. In the past, this goal was a preprogrammed fixed value, based on where the catalyst was believed to operate most efficiently. With the new downstream O2S fuel control, the upstream O2 goal is moved up and down, within the window of operation of the O2 Sensor. If the oxygen content leaving the catalyst is too lean (excess oxygen), the PCM will move the upstream O2 goal up, which will increase fuel in the mixture, causing less oxygen to be left over. Conversely, if the oxygen content leaving the catalyst is too rich (not enough oxygen), the PCM will move the upstream O2 goal down, which will remove fuel from the mixture, causing more oxygen to be left over.[/align][align=left][/align][align=left]This function only occurs during cruise mode operation. Currently, this function is not being used on 5.9L heavy-duty engines with automatic transmissions. The 5.9L heavy-duty vehicles do not have downstream O2 Sensors[/align]
As for answering your questions, no I haven't installed an air/fuel gauge, and have no intent on doing so, so long as I have a V6 in my truck. And yes, the purpose of cats are to clean the exhaust to meet emissions standards.
Personally, I don't care. If I had went through more than 1 cat, I would just killthe catand go from there. If my mileage started to suffer or it threw codes, I'd "work it out."
But yes, if your worried, or "have to have a cat" due to ****'s running your state, I'd go for a high-flow. But whatever you do, don't get a $300+ from-the-dealership cat.
Its cool, i wasnt trying to be an *** to you like i did that single post idiot in the other posts. I see where you got the info, its legit... but people have made ways to get around the 02s and still function properly, only if your deleting the cat. Otherwise.. i woudnt worry about it at all... for the most part some people just leave the c/e light on and pay 80$ cash for a inspection... hell once a year isnt that bad...
#27
08-26-2007, 01:47 AM
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RE: Exhaust questions
ORIGINAL: User2006
Its cool, i wasnt trying to be an *** to you like i did that single post idiot in the other posts. I see where you got the info, its legit... but people have made ways to get around the 02s and still function properly, only if your deleting the cat. Otherwise.. i woudnt worry about it at all... for the most part some people just leave the c/e light on and pay 80$ cash for a inspection... hell once a year isnt that bad...
Its cool, i wasnt trying to be an *** to you like i did that single post idiot in the other posts. I see where you got the info, its legit... but people have made ways to get around the 02s and still function properly, only if your deleting the cat. Otherwise.. i woudnt worry about it at all... for the most part some people just leave the c/e light on and pay 80$ cash for a inspection... hell once a year isnt that bad...
Hell, the computers have a code to tell you the O2 sensors are bad, but seem to rarely throws the code when they are. Probably wouldn't notice the differance if you just removed both of em
.
#28
08-26-2007, 02:34 AM
RE: Exhaust questions
ORIGINAL: dodgerules86
I understand where you are coming from: real life does differ from "textbook" theories.
Hell, the computers have a code to tell you the O2 sensors are bad, but seem to rarely throws the code when they are. Probably wouldn't notice the differance if you just removed both of em.
ORIGINAL: User2006
Its cool, i wasnt trying to be an *** to you like i did that single post idiot in the other posts. I see where you got the info, its legit... but people have made ways to get around the 02s and still function properly, only if your deleting the cat. Otherwise.. i woudnt worry about it at all... for the most part some people just leave the c/e light on and pay 80$ cash for a inspection... hell once a year isnt that bad...
Its cool, i wasnt trying to be an *** to you like i did that single post idiot in the other posts. I see where you got the info, its legit... but people have made ways to get around the 02s and still function properly, only if your deleting the cat. Otherwise.. i woudnt worry about it at all... for the most part some people just leave the c/e light on and pay 80$ cash for a inspection... hell once a year isnt that bad...
Hell, the computers have a code to tell you the O2 sensors are bad, but seem to rarely throws the code when they are. Probably wouldn't notice the differance if you just removed both of em
.
If i plug in my o2s the truck will stall and throw codes and all hell brakes loose.
Im going over to a friends tomorrow to find out if the wires are bad or if its the pcm.. I have a new PCM on the way, and if its the wires its going to suck cuz saudering upside down is NO fun...
#29
06-07-2013, 08:19 AM
1. Not all states require a cat on your vechicle... OK is one of them... if your headlights and horn work.. your good to go. Most states do require one though, but it isn't hard to get passed.
2. Are you kidding me? The 1/1 pre cat sensor has NOTHING to do with the cat itself.. so it woudn't rely on the cat to work. It read air/fuel mixture in the exhuast, the 1/2 post cat tells the computer if the cat is working properly, and if the cat goes bad it SOMTIMES tosses codes for it, simms help for awhile till they go bad and then throw codes, you can aslo tie the sensor to the rail.... and get no codes. Open loop actually dumps more fuel on throttle. Why do you think the truck runs a hell of alot better when you first start it up in the morning.. you can run rich and STILL produce More or = power. Not a 30% reduce did you pull that number out of your ***??? lol.. Post proof or dynos, becuase as many cars that ive seen get new exhuast and delete cats, not only does it sound better, but runs better (less restriction) and most of the time throws codes but can still get passed for a few extra bucks or a good hadheld.. o and your truck wont stay in open loop for deleting the cat. Open loop helps heat the engine to correct opperation temp and then will go to closed loop..
3. Ya you will, makes friends, bring an extra 50$ or reset the damn PCM before you go.. OBD2 emmsions doesn't do the exhuast sniffer, they go strickly by what the PCM says.. if no codes are showing it will pass...
Got any dynos for that exhuast system you put on? Cuz unless your have MAJOR mods done to the motor itself and was running STOCK exhuast and then upgraded to a set of headers, and a good free flowing exhuast.. I HIGHLY doubt you made 55hp. The best headers out there maybe give a gain of 10-15hp and the piping your lucky to get an extra 5 out of that. Proof or to me your Full of ****. As for your comments in your post right now i can tell you dont know ****.
2. Are you kidding me? The 1/1 pre cat sensor has NOTHING to do with the cat itself.. so it woudn't rely on the cat to work. It read air/fuel mixture in the exhuast, the 1/2 post cat tells the computer if the cat is working properly, and if the cat goes bad it SOMTIMES tosses codes for it, simms help for awhile till they go bad and then throw codes, you can aslo tie the sensor to the rail.... and get no codes. Open loop actually dumps more fuel on throttle. Why do you think the truck runs a hell of alot better when you first start it up in the morning.. you can run rich and STILL produce More or = power. Not a 30% reduce did you pull that number out of your ***??? lol.. Post proof or dynos, becuase as many cars that ive seen get new exhuast and delete cats, not only does it sound better, but runs better (less restriction) and most of the time throws codes but can still get passed for a few extra bucks or a good hadheld.. o and your truck wont stay in open loop for deleting the cat. Open loop helps heat the engine to correct opperation temp and then will go to closed loop..
3. Ya you will, makes friends, bring an extra 50$ or reset the damn PCM before you go.. OBD2 emmsions doesn't do the exhuast sniffer, they go strickly by what the PCM says.. if no codes are showing it will pass...
Got any dynos for that exhuast system you put on? Cuz unless your have MAJOR mods done to the motor itself and was running STOCK exhuast and then upgraded to a set of headers, and a good free flowing exhuast.. I HIGHLY doubt you made 55hp. The best headers out there maybe give a gain of 10-15hp and the piping your lucky to get an extra 5 out of that. Proof or to me your Full of ****. As for your comments in your post right now i can tell you dont know ****.
The states have nothing to do with laws pertaining to cats. The federal law requires vehicles produced after 1974 to have a working catylytic convertor. If your state doesn't make you have them, they are breaking the law, along with you. Oh yeah Einstein, both 02 sensors do work together, to properly tune your vehicle, as the guy who answered you tried to explain to you. The more information the computer has the better it will work for performance, mileage and emissions
#30
06-07-2013, 08:44 AM
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The states have nothing to do with laws pertaining to cats. The federal law requires vehicles produced after 1974 to have a working catylytic convertor. If your state doesn't make you have them, they are breaking the law, along with you. Oh yeah Einstein, both 02 sensors do work together, to properly tune your vehicle, as the guy who answered you tried to explain to you. The more information the computer has the better it will work for performance, mileage and emissions
I'm going to clarify this for others, the vehicles are required by federal law to be "produced" with cats on them. So when the vehicle rolls out of the factory and is sold by a dealer it must have it. Operations and minimal maintenance requirements of vehicles are regulated at the state level.