O2 codes

[wytbishop]

Ok...so this is the issue. The previous owner of the Purple Beast removed the catalytic converter when he replaced the exhaust a few years back. So naturally I've been throwing a code all this time and my mileage sucks. Have any of you found a creative way to make the car work without a cat and without throwing a code?

I suppose I should just replace the cat and reset the ECU, but it's such a pain. Any input would be appreciated.

[shameem]

3 options -
1)Put a new cat and reset computer
2)Use MIL eliminator - http://www.msprotege.com/forum/showpost ... tcount=478" onclick="window.open(this.href);return false;
3)Use spark plug non fouler - http://www.msprotege.com/forum/showthre ... =123634664" onclick="window.open(this.href);return false;

[wytbishop]

That is very interesting. Thanks for that.

[fowljesse]

I hollowed out my cat years ago, because it was clogged (Never got around to replacing it) and never got a code, and passed emmissions (with a little help from Acetone).

[Daninski]

Why would a cat cause you to throw a code? There's no sensor other than on the exhaust manifold. What is the code number your throwing?

[shameem]

obd2 cars use two (or more) sensor readings to determine cat efficiency - one before cat and one after cat - the after cat one is monitored by the ECU to estimate the "health" of the cat. If the cat is hollowed out then the ECU would throw a cat efficiency below threshold code or something like that......

[wytbishop]

Yeah...I was thinking about what Dan said too...My OBD1 car doesn't have a sensor on either side of the cat. I don't think these fixes would work for me. Maybe I do just have a bad sensor.

[Daninski]

I just replace both of mine and no code now for me. shameen, I know some cars have one after the cat but the 96-97 MX3s don't. Both sensors are before the cat. First one being a sensor and the second being a sensor monitor that you can actually eliminate with no issues.

[wytbishop]

What did you buy to replace them Dan? Were they plug n' play or did you have to do some wiring?

[Daninski]

I bought Denso OEM direct fit from Rockauto for both my 96 MX3 and my 94 MX6. Someone yesterday said oxygensensors.com was good to deal with. If the Denso's are too pricey the guys on MX6.com said Walker O2 sensors work really well with Mazda too.

[shameem]

My bad - i assumed he was talking about obd2 since he talked about a cat code....

Its funny because last week i talked to someone with a 95 RS up in kalamazoo and she has "partial" obd2 and throwing a cat efficiency code (P0420 - funny number i know)- in her case the cat is rusted out and leaking......

[wytbishop]

I'm gonna replace the sensors and clear the codes and see if the fuel efficiency improves.

Thanks for your help guys.