overall i want better mpg! My cel is always on and when i ran a test it came back saying i have no cat (i already knew)
problem im trying to solve is my oxygen sensors. I had a guy jack up my car and we looked under it and there obviously arent any cats and theres nothing where the o2 sensors are suppose to be. My set up is a Greddy sp1 exhaust duel resonaed (sp) mid pipe. Thats all i know, i bought the car with the exhaust already installed. So from what ive explined your saying i should be able to connect o2 sensors to my mid pipe? Like there should be a place to cnnect them? Because when we looked the guy said theonly way id be able to do it is if we installed a cat. Idk if they just wanted money or what but i just want more that 180 miles per tank.

 

You need two sensors hooked up. The front one is the most important, IIRC. If you dont have the front one, you are not using LTFT or STFT and you are lucky that you are rich and not lean. But the front sensor is in the manifold. You have that one right?


You can very easily have an wbo2 bung welded on. But there should be at least one already, IIRC. Gotta be. The one post cat (what was post cat) is the narrowband. Not sure what the effect of disconnecting this one is. Might be nothing but a cel. Do you have the sensor in the manifold? That one is the wideband. That one is very important.

Sensors are expensive(ish).

 

Ok so i apparently need sensors..i cant remember if there were any under there o not..if not then i need 2..
Where do itake my car to get it fixed?
who can make holes for O2 sensors if non are already present and how do they know where to put it/them? Im located in southern california north of san diego so does anyone know of a place to have it fixed around here?

 

FIRST thing you gotta do is get the actual code that the computer is displaying.

You need a code reader, ($50 or so) or take it to a place that can read them.

The code will be a number, this we can diagnose.

There is a list in the tech section.

It could be any of a thousand codes, but it is very likely a P0420(cat efficiency) caused by having no cat.

That will cause a check engine light, but nothing else, no rich running, no poor mileage.

You may have a broken FRONT sensor, this is much more serious, and best fixed by the dealer, it is a bitch to change and expensive.

In neither case will spark plug anti-foulers do squat.

Until you find the code, any advice is just guesses, we CAN help, but you gots to do some of the legwork.......

 

that is the code, i had a friend hook up his reader and thats what came up.
he said its apparently from not having a cat.
if i take the car to mazda can they put my sensors on or back on and if so will they drill holes for the plugs in the mid pipe?

 

Stealth has a very good point. Whether you have a rear sensor or not may be a red herring.

To diagnose the issue, we need the specific code so as to know exactly what is going on, before doing anything else. What is the numeric code?

Are you still under warranty?

 

PO420 is the code as i stated in my last post, and the car only has 75k so isnt it still under the mazda 100k warranty? Its a 2004

 

I agree you yourself better look under there and see if there's a bung for a sensor which theere SHOULD b....

 

The reason I asked about the warrenty is that if you go to the dealer without emissions control, you might lose it (the warranty).

Try searching for P0420 here and look at the list of codes. Might get something from that.

I dont think that this indicates that the front sensor is bad. Only the rear (which apparently is not there)

I also do not think that this would explain running overly rich, or at least no more richer than normal. The RX8 is not a fuel sipping car.

All in all sounds like you need to buy an AP and tune it or buy a cat. I dont think anything is "broken." It isn't stock, but we understand that.