Maybe some advice would be wise before I do this...
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Champion
Joined: Aug 2010
Posts: 2,697
Likes: 3
From: Cape Carteret NC
Maybe some advice would be wise before I do this...
Howdy...
I have a '02 cali emissions 5.9L... it 'had' three cats OE.. one on each back just south of the collector, and one great big ol' fat thing.. It now has four.. the same two just behind the collectors(one each), and two magnaflow high flow's.. I run them into a magnaflow tru-x muffler, and now have dual X exhaust..
I have an exhaust leak that has finally pushed me over the edge.. I have a set of remflex gaskets, and stage-8 header bolts staged to install.. I also have header wrap, and sealer- along with some high temperature paint (to touch up, but enough for a whole new coat)..
I live on the coast of NC, which is laterally, as far as you can get from Cali and still be in the US and dry.. There are no emissions tests here.. But, there is a visual test..
Is it worth it to punch out those pre-cats? They are OE, and have 165k miles on them.. I fixed the plenum gasket at around 145, and suspect they are at least a little tired.. This would be the perfect opportunity to do so, because I hope to not have to mess with exhaust for a good while after this... Has anyone here had a rig with the pre-cats and removed them?
I have a '02 cali emissions 5.9L... it 'had' three cats OE.. one on each back just south of the collector, and one great big ol' fat thing.. It now has four.. the same two just behind the collectors(one each), and two magnaflow high flow's.. I run them into a magnaflow tru-x muffler, and now have dual X exhaust..
I have an exhaust leak that has finally pushed me over the edge.. I have a set of remflex gaskets, and stage-8 header bolts staged to install.. I also have header wrap, and sealer- along with some high temperature paint (to touch up, but enough for a whole new coat)..
I live on the coast of NC, which is laterally, as far as you can get from Cali and still be in the US and dry.. There are no emissions tests here.. But, there is a visual test..
Is it worth it to punch out those pre-cats? They are OE, and have 165k miles on them.. I fixed the plenum gasket at around 145, and suspect they are at least a little tired.. This would be the perfect opportunity to do so, because I hope to not have to mess with exhaust for a good while after this... Has anyone here had a rig with the pre-cats and removed them?
Banned Goober Smoocher
Joined: Jun 2010
Posts: 8,916
Likes: 1
EXACTLY!
That is what I am talking about.
That is what I am talking about.
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Champion
Joined: Aug 2010
Posts: 2,697
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From: Cape Carteret NC
the codes are manageable, I'm willing to bet.. I've played with o2 sensors for a while now, and think I can manipulate them to believe whatever I want them to believe..
the sensor isn't so smart.. it simply sniffs air inside the tube, as well as outside.. the bulging part has a protected strand of a special type of conductive material that registers difference in present o2 in voltage.. it sends that voltage to mr. PCM.. Mr. PCM determines if those volts are in a suitable parameter..
the upwind sensor is crucial, but it won't really be messed with during the field dressing..
the downwind sensor is absolutely in play for fuel trim, BUT, it isn't as important as the upwind.. from what I've researched, the PCM takes the voltage difference from the upwind and uses it to trim fuel.. then the downwind voltages are pushed through a formula to fine tune the trim with what is going on upwind..
VERY loose example not using ANYTHING close to real data:
upwind: .3 volts between inside and outside..
Mr. PCM: we're lean, add fuel..
downwind: .02 between inside and outside..
Mr. PCM: I know that upwind sees .3vdc, and downwind sees .02vdc, and I know that a properly functioning catalyst should shave somewhere around 40% off of it, so the cat is doing it's job~ however, bumping the fuel .1% will increase the upwind reading, and keep the downwind within parameters as well.. I'm giving it a shot and seeing what happens.. because I can.. I'm Mr. Mysterious Master of the floggin' truck..
con't...
anyway, you can manipulate the downwind sensor from inside the stream or from outside.. the inside is pretty easy (non-fouler), the outside is a little tougher (reducing the flow by partially blocking the ports).. I'll figure it out if a code pops up.. those things themselves aren't too smart.. Mr. PCM is.. but he can only make decisions based on the information presented, dig it?
I think I'm going to do it.. I've only heard one voice of dissension over the several forums I've asked this in..
the sensor isn't so smart.. it simply sniffs air inside the tube, as well as outside.. the bulging part has a protected strand of a special type of conductive material that registers difference in present o2 in voltage.. it sends that voltage to mr. PCM.. Mr. PCM determines if those volts are in a suitable parameter..
the upwind sensor is crucial, but it won't really be messed with during the field dressing..
the downwind sensor is absolutely in play for fuel trim, BUT, it isn't as important as the upwind.. from what I've researched, the PCM takes the voltage difference from the upwind and uses it to trim fuel.. then the downwind voltages are pushed through a formula to fine tune the trim with what is going on upwind..
VERY loose example not using ANYTHING close to real data:
upwind: .3 volts between inside and outside..
Mr. PCM: we're lean, add fuel..
downwind: .02 between inside and outside..
Mr. PCM: I know that upwind sees .3vdc, and downwind sees .02vdc, and I know that a properly functioning catalyst should shave somewhere around 40% off of it, so the cat is doing it's job~ however, bumping the fuel .1% will increase the upwind reading, and keep the downwind within parameters as well.. I'm giving it a shot and seeing what happens.. because I can.. I'm Mr. Mysterious Master of the floggin' truck..
con't...
anyway, you can manipulate the downwind sensor from inside the stream or from outside.. the inside is pretty easy (non-fouler), the outside is a little tougher (reducing the flow by partially blocking the ports).. I'll figure it out if a code pops up.. those things themselves aren't too smart.. Mr. PCM is.. but he can only make decisions based on the information presented, dig it?
I think I'm going to do it.. I've only heard one voice of dissension over the several forums I've asked this in..
Record Breaker
Joined: Nov 2010
Posts: 1,400
Likes: 0
From: Charleston, SC
the codes are manageable, I'm willing to bet.. I've played with o2 sensors for a while now, and think I can manipulate them to believe whatever I want them to believe..
the sensor isn't so smart.. it simply sniffs air inside the tube, as well as outside.. the bulging part has a protected strand of a special type of conductive material that registers difference in present o2 in voltage.. it sends that voltage to mr. PCM.. Mr. PCM determines if those volts are in a suitable parameter..
the upwind sensor is crucial, but it won't really be messed with during the field dressing..
the downwind sensor is absolutely in play for fuel trim, BUT, it isn't as important as the upwind.. from what I've researched, the PCM takes the voltage difference from the upwind and uses it to trim fuel.. then the downwind voltages are pushed through a formula to fine tune the trim with what is going on upwind..
VERY loose example not using ANYTHING close to real data:
upwind: .3 volts between inside and outside..
Mr. PCM: we're lean, add fuel..
downwind: .02 between inside and outside..
Mr. PCM: I know that upwind sees .3vdc, and downwind sees .02vdc, and I know that a properly functioning catalyst should shave somewhere around 40% off of it, so the cat is doing it's job~ however, bumping the fuel .1% will increase the upwind reading, and keep the downwind within parameters as well.. I'm giving it a shot and seeing what happens.. because I can.. I'm Mr. Mysterious Master of the floggin' truck..
con't...
anyway, you can manipulate the downwind sensor from inside the stream or from outside.. the inside is pretty easy (non-fouler), the outside is a little tougher (reducing the flow by partially blocking the ports).. I'll figure it out if a code pops up.. those things themselves aren't too smart.. Mr. PCM is.. but he can only make decisions based on the information presented, dig it?
I think I'm going to do it.. I've only heard one voice of dissension over the several forums I've asked this in..
the sensor isn't so smart.. it simply sniffs air inside the tube, as well as outside.. the bulging part has a protected strand of a special type of conductive material that registers difference in present o2 in voltage.. it sends that voltage to mr. PCM.. Mr. PCM determines if those volts are in a suitable parameter..
the upwind sensor is crucial, but it won't really be messed with during the field dressing..
the downwind sensor is absolutely in play for fuel trim, BUT, it isn't as important as the upwind.. from what I've researched, the PCM takes the voltage difference from the upwind and uses it to trim fuel.. then the downwind voltages are pushed through a formula to fine tune the trim with what is going on upwind..
VERY loose example not using ANYTHING close to real data:
upwind: .3 volts between inside and outside..
Mr. PCM: we're lean, add fuel..
downwind: .02 between inside and outside..
Mr. PCM: I know that upwind sees .3vdc, and downwind sees .02vdc, and I know that a properly functioning catalyst should shave somewhere around 40% off of it, so the cat is doing it's job~ however, bumping the fuel .1% will increase the upwind reading, and keep the downwind within parameters as well.. I'm giving it a shot and seeing what happens.. because I can.. I'm Mr. Mysterious Master of the floggin' truck..
con't...
anyway, you can manipulate the downwind sensor from inside the stream or from outside.. the inside is pretty easy (non-fouler), the outside is a little tougher (reducing the flow by partially blocking the ports).. I'll figure it out if a code pops up.. those things themselves aren't too smart.. Mr. PCM is.. but he can only make decisions based on the information presented, dig it?
I think I'm going to do it.. I've only heard one voice of dissension over the several forums I've asked this in..
I like that, sounds like my rigs PCM
Legend
Joined: Jul 2011
Posts: 8,259
Likes: 4
From: Austin, TX
the codes are manageable, I'm willing to bet.. I've played with o2 sensors for a while now, and think I can manipulate them to believe whatever I want them to believe..
the sensor isn't so smart.. it simply sniffs air inside the tube, as well as outside.. the bulging part has a protected strand of a special type of conductive material that registers difference in present o2 in voltage.. it sends that voltage to mr. PCM.. Mr. PCM determines if those volts are in a suitable parameter..
the upwind sensor is crucial, but it won't really be messed with during the field dressing..
the downwind sensor is absolutely in play for fuel trim, BUT, it isn't as important as the upwind.. from what I've researched, the PCM takes the voltage difference from the upwind and uses it to trim fuel.. then the downwind voltages are pushed through a formula to fine tune the trim with what is going on upwind..
VERY loose example not using ANYTHING close to real data:
upwind: .3 volts between inside and outside..
Mr. PCM: we're lean, add fuel..
downwind: .02 between inside and outside..
Mr. PCM: I know that upwind sees .3vdc, and downwind sees .02vdc, and I know that a properly functioning catalyst should shave somewhere around 40% off of it, so the cat is doing it's job~ however, bumping the fuel .1% will increase the upwind reading, and keep the downwind within parameters as well.. I'm giving it a shot and seeing what happens.. because I can.. I'm Mr. Mysterious Master of the floggin' truck..
con't...
anyway, you can manipulate the downwind sensor from inside the stream or from outside.. the inside is pretty easy (non-fouler), the outside is a little tougher (reducing the flow by partially blocking the ports).. I'll figure it out if a code pops up.. those things themselves aren't too smart.. Mr. PCM is.. but he can only make decisions based on the information presented, dig it?
I think I'm going to do it.. I've only heard one voice of dissension over the several forums I've asked this in..
the sensor isn't so smart.. it simply sniffs air inside the tube, as well as outside.. the bulging part has a protected strand of a special type of conductive material that registers difference in present o2 in voltage.. it sends that voltage to mr. PCM.. Mr. PCM determines if those volts are in a suitable parameter..
the upwind sensor is crucial, but it won't really be messed with during the field dressing..
the downwind sensor is absolutely in play for fuel trim, BUT, it isn't as important as the upwind.. from what I've researched, the PCM takes the voltage difference from the upwind and uses it to trim fuel.. then the downwind voltages are pushed through a formula to fine tune the trim with what is going on upwind..
VERY loose example not using ANYTHING close to real data:
upwind: .3 volts between inside and outside..
Mr. PCM: we're lean, add fuel..
downwind: .02 between inside and outside..
Mr. PCM: I know that upwind sees .3vdc, and downwind sees .02vdc, and I know that a properly functioning catalyst should shave somewhere around 40% off of it, so the cat is doing it's job~ however, bumping the fuel .1% will increase the upwind reading, and keep the downwind within parameters as well.. I'm giving it a shot and seeing what happens.. because I can.. I'm Mr. Mysterious Master of the floggin' truck..
con't...
anyway, you can manipulate the downwind sensor from inside the stream or from outside.. the inside is pretty easy (non-fouler), the outside is a little tougher (reducing the flow by partially blocking the ports).. I'll figure it out if a code pops up.. those things themselves aren't too smart.. Mr. PCM is.. but he can only make decisions based on the information presented, dig it?
I think I'm going to do it.. I've only heard one voice of dissension over the several forums I've asked this in..
Go for it! I am sure you can figger a way to outsmart Mr. PCM. Although I don't have a cali rig or emission testing here, I will be interested in the results.