Another question. Does the ECU reset itself when you pull the straight pipe and put the CAT back on?

 

doubt it.... maybe it will after a while. u should juss disconnect your negative battery.

 

Yeah, makes sense. I just wondered if the sensor would pick up the change with the CAT back on and stop the CEL.

 

Yeah, actually the illegal-ness of it wasn't the big issue for me. I did like the sound and the extra power. Swapping it back and forth wasn't that big of a deal either.

But, you nailed it exactly with the "go cart" smell. That was the primary reason I sold it. The smell of chainsaws, motorbikes, and snowmobiles just wasn't for me.

Glad to hear you're enjoying it dtorre - especially the fire part!

 

Whoever said that is either confused, crazy, or lying. Or you misinterpreted something. The AEM/Mazdaspeed CAI will give no CEL.

Yes they are identical, the Mazdaspeed CAI is a copy of the AEM.

 

Running Midpipe for a while. No CEL. No Odor. I read a thread, some chick, passed with Midpipe. I have stock exhaust. Best Mod that I have bought. After ECU full reset will help clean up the smell. I think it has adjusted enough after reset to calibrate for emmisions. I have the breather on the Oil stem. So those emissions will not go through the tail pipe. I think I can pass. Just speculation.

 

heh. How do you think the ECU reset would magically clean up your exhaust? No cat means no cat.

 

Exactly.

Having no cat means your HC's will go through the roof. There are some areas that on newer cars they do no visual, no sniffer, only hook a scan tool up to the car and check for any codes. No codes = pass. So it is technically possible to pass without a cat in those areas if you have no CEL.

 

Just speculation. Reason: The ECU monitors the MAF and O2, to adjust mixture. If I am not getting a CEL, that would leave me to believe so. I anticipated a CEL from the get go. I have done this on many cars, they all throw a CEL. I speculate again: As long as the ECU can make sense of the I/0 from the MAF and o2, all is good. I can not find any other explination for it. Why is there no CEL or bad odors. Ther is a slight, I mean slight smell every once in a while.

My reasoning for the midpipe was for trouble shooting purposes. I got my answer, which was a bad CAT. I am in no hurry to put a good CAT back on. No way.

 

The car can do nothing to lower or "fix" your exhaust emissions if the cat is missing. It is burning fuel, no matter what your car thinks or does, by simply running, your can WILL emit more hydrocarbons and carbon monoxide than it would with a cat.

The ECU has is a list of checks to perform. If you hit all the checks (specific time at different rpm or speed ranges) and the sensor detects a malfunctioning cat, you'll get the CEL.

I used to get a CEL within 10-15 miles when I was catless. I'm currently running with a turbo and my car doesn't get a CEL, and it's been several hundred miles.

I can't explain the lack of a CEL, but I can guarantee you that the car's ECU is unable to fix the problem of a missing cat. In fact, if the ECU (as you claim) is aware of the missing cat and can correct it, it would also stand to reason that the car would light up the CEL for emissions hardware malfunctioning.

 

I've had 2 different aftermarket midpipes over the past 30-35k miles, never got a CEL with either (except when the cat fell apart on the first one).

 

The CAT has two stages. There is a empty gap between them. The O2 plugs into that gap. If the back section is damaged, there is no way for the O2 to know that. That is why my car had 80 HP. The dealer will not pull it unless a CEL. I wonder why they put it there instead of behind the second stage. The first stage is very small, in comparision. You can find some images on the forum. So guy found a way to gut just the rear section, which is crazy to imagine. So I guess my question is what does the O2 look for besides temp? Reason I am asking, is because of the small stage before it hits the O2. It goes through a fraction of the CAT before sending its readings.

 

quick question all u guys with the midpipe...what did u use to get the O2 sensor off? what size socket is it? I looked in the mazda workshop manual and it takes a special mazda tool that doesnt have a specific size...Im new to all this DIY...

 

I just used a wrench.. no idea what size it was. But it wasn't a special wrench either.

 

There are O2 sensor sockets available at just about any automotive parts store.

A person can also use a combination wrench to loosen the sensor from the pipe.


I was running a custom midpipe with the extender mod built in. No CEL after 700 miles.

Installed the Racing Beat 3" pipe and at 31 miles the CEL came on for it.

Will be getting the extender because that was the only difference between the two pipes.