I just wanted to share my experience because when I was looking for answers here I had some trouble finding them.

A few months ago I decided to replace my cat for a cat-delete, and most of you know that the ECU will throw CEL P0420 (Catalyst System Efficiency Below Threshold, Bank 1). You may say the solution is the O2 mechanical fix, but in my case installing 2 spark plug anti-foulers in a row plus the O2 sensor was not an option. The problem is that the O2 bung on the test-pipe is kinda pointing to the ground, and that would place the O2 sensor too close to the ground. There was a long TBE group buy thread that had people trying to find options for this problem. Basically we're trying to find a 90-degree fitting elbow to use instead of one of the anti-foulers, but it took forever because the part had to be custom made. We found this picture, but we're far from being able to reproduce the part.



The other option was installing the Perrin O2 simulator, but $60 for it was too much.

I decided to take a look on the Internet for O2 simulators and found many places selling what it's called MIL eliminators. On eBay you can get these for $9.95 shipped, so I decided to give them a try. I contacted one of the vendors on eBay and he sent me one that was supposed to work OK on Mitusibishi cars, it looks exactly like this:



The wiring color on the MIL eliminator matched perfectly the wiring color on the O2 sensor underneath the car, so installation was really easy. After erasing the P0420 code on the ECU I started the car and drove it for a while, everything went fine. Later on I had a CEL, I thought it was P0420 again but after checking it was P0139 (02 Sensor Circuit Slow Response, Bank 1 Sensor 2). Found some info about it here as well as on other forums, apparently the way our ECU works won't allow us to use a MIL eliminator, every ~32 miles our ECU runs a diagnostic test and will find something wrong with the O2 sensor, so I was out of luck. At least the MIL eliminator did its job, too bad it caused another code in exchange.

I was about to buy the Perrin O2 simulator but I decided to contact the MIL eliminator seller first. I wasn't trying to get my money back, I just wanted to let him know that his product didn't work as expected. He wasn't aware of the problem, but offered his help to get the solution. He sent me an O2 simulator that he was working on but hadn't tried on an Evo. The O2 simulator looks like this:



Since this was the first time installing this O2 simulator on the Evo it took me some time to get it working (we weren't sure about what wires we had to use on the Evo wiring, so I used a multimeter), but now I can say that installation won't take more than 5 minutes once you've removed the passenger seat.

I have used this O2 simulator for 2 weeks/500 miles without one single CEL, it works great. For $24.95 you can't go wrong.

For more info you can go to this site and contact the seller directly, very nice and helpful guy:

http://www.mileliminatorsonline.com/

 

Nice write up.

 

very nice

 

That is the one i have but in black from http://mysite.verizon.net/vze7erz1/index.html

 

Nice, I was lookin into an o2 fix because the stupid light is annoying. I hate goin to autozone every week and asking to use their obd2 scanner. I am definitely going to look into this option over a mech o2 fix.

 

So, when you use that thing you don't even connect your rear O2 sensor?

 

Nice write up. I tried the mechanical one, worked for a while, but then water kept collecting in the sensor/wire and would throw a CEL.

I got the Perrin O2 one from JSC speed for $52 bucks shipped. It arrived the very next day


I assume you could install that one in the center console as well.

 

I assume you do. You prolly just tee into some of the wires like with the perrin.

 

Can you put the antifoulers into where the 02 sensor is located originally? [after the cat]?

 

I have a setup just like the one pictured. It's not a custom made piece, it's a standard NPT 90. You can get them at a lot of auto parts stores or home depot. I believe it was 3/8" NPT, but I'm not 100% sure. All you do is screw the male end into a spark plug anti-fouler (not an exact fit, but if you get it tight it will hold). Then you retap the female side to the same thread size as the spark plug anti-foulers and O2 sensor. Then screw a drilled out anti-fouler into the newly tapped hole and screw the O2 sensor into the anti-fouler. It's a pretty easy job.

-Paul

 

You don't need to connect the rear O2 sensor because the O2 simulator is creating the signal needed by the ECU. This simulator is also useful when you need the O2 bung for a wideband, this would not be possible when using the anti-foulers.

 

You can use this O2 simulator in the center console or under the passenger seat. It's way easier to connect it under the seat, and you can check if the light is blinking anytime, in the center console would not be possible unless you take it apart again.

 

So what wires do you need to splice into? Any chance you took a pic of the install?

 

I know some people (including myself) tried to find something like what you described, but we all failed. We went to Home Depot, Autozone, Napa, Pep Boys, etc., but there was nothing that big, only small 90-degree fitting elbows. Now that I installed this O2 simulator I can say that spending $25 for it is cheaper than driving to the auto parts for the anti-foulers and fitting elbow, then driving again to some place that can make the elbow fit, plus the cost of the parts and labor. Your solution was the option I was trying to use, but at that time I didn't know there was this other option. Now I'm happy with it.

 

Wiring was easy after all. The O2 simulator has 3 wires: red (+12V), black (ground), and yellow (signal). Under the passenger seat there is a piece of carpet that covers the O2 plug. One side has the 4 wires coming from the O2 sensor, the other has the wires going to the ECU. Colors on each side are different, so I had to use a multimeter just to make sure that I was using the correct wires. I decided to splice into the O2 sensor wires because if I messed something up it would be on the O2 sensor side of the plug and that could be replaced easily. Wires go like this:

PLUG -- O2 SENSOR ------------------- to ECU
-------- 1 = black (heater +12V) <==> red
| 1 2 | 2 = black (heater ground) <==> blue
| 3 4 | 3 = white (ground) <==> black
-------- 4 = blue (O2 signal) <==> white

The red wire on the O2 sim must be connected to the black 1 (or red on the other side of the plug). The black wire on the O2 simulator must be connected either to the chassis or to white wire on the O2 sensor side (black wire on the other side of the plug). Finally you need to cut the blue wire on the O2 sensor (or white wire on the other side of the plug) and connect the yellow wire on the O2 sim to it. This yellow wire should be connected to the side that goes to the ECU, not to the side going to the O2 sensor.

Pretty easy installation. I'll remove my passenger seat and take pictures this weekend.