NB Cat Delete CEL fix question
#1
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NB Cat Delete CEL fix question
I know most of you guys are pretty significantly modded, but hopefully someone has addressed this... My daily is a stock 99 miata w/ racing beat exhaust. The exhaust does not have a cat, but it has a secondary o2 sensor tapped in it. The sensor is extended from the exhaust a bit, apparently in an attempt to make it not throw a code. Unfortunately it still throws a code every couple hundred miles or so. If I just pull the sensor and tie it up somewhere under the car, then plug the whole in the exhaust, will I still throw a code? Any other options I could consider other than the "black tape over the CEL" method? Thanks.
#3
A simulator is illegal, so whatever I write in this post is purely hypothetical. This fix may or may not be working great in my car.
Car had a CEL for "emissions too close to threshold" or something like that after a few months with a high-flow metalcore cat.
Under the driver's seat, very close to the trans tunnel, is a plastic-wrapped series of four wires. This is where the wires exit the car and go underneath to the rear O2 sensor.
Cut open the plastic wrap. The four wires (on an '04 at least) are: 1., black with white stripe (power), 2., white (signal in), 3., red (mostly wrapped in a second layer of white insulation - signal out), 4., black with red stripe (sensor ground).
Cut the red and black/red wires. Install a 1 megaohm resistor (1/4-watt or 1/2 watt) in the red wire. Then install a 1 microfarad capacitor jumping the red and black/red wires, forward of the resistor. Cover the wires with electrical tape or (better yet) heat-shrink tubing. I used electrical tape but I'm told it could melt over time.
Done.
This sends an acceptable voltage to the ECU, so it thinks all is well. (These aren't the droids we're looking for .... move along .....)
Car had a CEL for "emissions too close to threshold" or something like that after a few months with a high-flow metalcore cat.
Under the driver's seat, very close to the trans tunnel, is a plastic-wrapped series of four wires. This is where the wires exit the car and go underneath to the rear O2 sensor.
Cut open the plastic wrap. The four wires (on an '04 at least) are: 1., black with white stripe (power), 2., white (signal in), 3., red (mostly wrapped in a second layer of white insulation - signal out), 4., black with red stripe (sensor ground).
Cut the red and black/red wires. Install a 1 megaohm resistor (1/4-watt or 1/2 watt) in the red wire. Then install a 1 microfarad capacitor jumping the red and black/red wires, forward of the resistor. Cover the wires with electrical tape or (better yet) heat-shrink tubing. I used electrical tape but I'm told it could melt over time.
Done.
This sends an acceptable voltage to the ECU, so it thinks all is well. (These aren't the droids we're looking for .... move along .....)
#4
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the 2nd o2 sensor in every vw, honda, subaru, or yugo I've ever worked on was just a check sensor to make sure the cat works...so you can hang it outside the exhaust pipe and it won't throw codes.
#5
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Ahh, thanks for the info. I'll have to look into the simulator, that stupid light drives me crazy. I always have to reset the ecu right after it comes on. I have figured out that if you pull the battery off for right around 20 seconds it resets the ecu, but leaves the radio presets and trip odometer.
edit: Thanks for the writeup evank! That's a lifesaver.
edit: Thanks for the writeup evank! That's a lifesaver.
#6
A simulator is illegal, so whatever I write in this post is purely hypothetical. This fix may or may not be working great in my car.
Car had a CEL for "emissions too close to threshold" or something like that after a few months with a high-flow metalcore cat.
Under the driver's seat, very close to the trans tunnel, is a plastic-wrapped series of four wires. This is where the wires exit the car and go underneath to the rear O2 sensor.
Cut open the plastic wrap. The four wires (on an '04 at least) are: 1., black with white stripe (power), 2., white (signal in), 3., red (mostly wrapped in a second layer of white insulation - signal out), 4., black with red stripe (sensor ground).
Cut the red and black/red wires. Install a 1 megaohm resistor (1/4-watt or 1/2 watt) in the red wire. Then install a 1 microfarad capacitor jumping the red and black/red wires, forward of the resistor. Cover the wires with electrical tape or (better yet) heat-shrink tubing. I used electrical tape but I'm told it could melt over time.
Done.
This sends an acceptable voltage to the ECU, so it thinks all is well. (These aren't the droids we're looking for .... move along .....)
Car had a CEL for "emissions too close to threshold" or something like that after a few months with a high-flow metalcore cat.
Under the driver's seat, very close to the trans tunnel, is a plastic-wrapped series of four wires. This is where the wires exit the car and go underneath to the rear O2 sensor.
Cut open the plastic wrap. The four wires (on an '04 at least) are: 1., black with white stripe (power), 2., white (signal in), 3., red (mostly wrapped in a second layer of white insulation - signal out), 4., black with red stripe (sensor ground).
Cut the red and black/red wires. Install a 1 megaohm resistor (1/4-watt or 1/2 watt) in the red wire. Then install a 1 microfarad capacitor jumping the red and black/red wires, forward of the resistor. Cover the wires with electrical tape or (better yet) heat-shrink tubing. I used electrical tape but I'm told it could melt over time.
Done.
This sends an acceptable voltage to the ECU, so it thinks all is well. (These aren't the droids we're looking for .... move along .....)
#14
1) do the resistor mod
2) ignore the cel
3) put in a good cat
#17
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You guys saying it would still throw a code were right. I made it 10 miles and it came on again. I've run the anti-foulers on my old s2000 and never had a problem. The exhaust I have is already extended enough that I don't have room for the anti-fouler and that's not enough. I'm going to try to the resister mod when I get some time.
#20
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That there's yer problem.
Git you one a them fancy simulators fer forty bucks and be done wid it.
Universal o2 simulator single output [unv-o2sim1] - $40.00 : O2 Simulator, E-commerce
Problem solved. And solved correctly.
Git you one a them fancy simulators fer forty bucks and be done wid it.
Universal o2 simulator single output [unv-o2sim1] - $40.00 : O2 Simulator, E-commerce
Problem solved. And solved correctly.