Exhaust CEL

[Nepharius]

Well I got the new exhaust from Daz installed in my car and after a few hours it has thrown up a CEL. Daz mentioned that for 5k his car put up a warning that said something about the cat not getting up to temp but eventually went away. I don't have a scanguage so I cant check to see if thats what my car is claiming nor can I just reset it(well without resetting battery).

The exhaust got rid of the first cat so I kind of figured it may be something to do with that. I've heard some people mention you can trick the system to make the CEL go away how do you go about doing that?

Also I havent really noticed any odd behaviour with the light on does it have an effect on the car at all? I think I read somewhere it causes it to run super rich. I want to try and fix this up before I get the car tuned some time in the future.

[tricache]

Removing the first cat will be your problem as the o2 sensors in the exhaust system work but matching readings, when they get a different reading (obviously the first and second sensor will get a different reading due to the first cat not being there anymore) they will set off a CEL.

I came across this problem with alot of the NA guys years ago, I will have to go through some of the old posts on OMC to see what they did to fix the problem.

[Penguin740]

I know with my exhaust installed by CES they had to move one of the O2 sensors, which required an auto electrician to extend the cable running to it.

I beleive this stops the CEL. Try PMing 2XS (check the forum names) as he built my exhaust while he was working at CES.

[kagerou]

what brand down pipe did you get?

the following will only apply if you got a a cp-e or cobb downpipe, or a corksport downpipe and didnt get the mid pipe section as well

if the new downpipe has an aftermarket cat in there, then the sensors wont be getting matching readings because the sensors will be relocated before and after the cat

it will probably be the error code where the second sensor reads the exhaust as being rich, so it throws the code about the catalytic converter not reaching temperature, or the catalytic converter failure

best way is to plug in a dash hawk to get the error code, and to monitor the voltage readings on the second o2 sensor, which should be between 0v and 1v

the sensor needs to warm up first, which takes about 5 minutes of driving, and will read 20mv - 25mv until it is at operating temperature

[Nepharius]

Hmm I've found this on the net, would this work or is it a really stupid idea?
How TO: CEL/MIL Eliminator! - Mazda Forums

As for the dumpipe its a custom job from Sydney. I'm pretty sure it didnt have a socket for the second O2 sensor after the cat not to mention the exhaust shop didnt mention having to get an auto electrician to modify my sensor as part of their marathon install.

[kagerou]

that will only work if you know you are getting the issue with the second o2 sensor reading too high, ie. over 1v

find someone with a scangauge or dash hawk, and see what error you have

i would try to avoid cutting up the o2 sensor wiring and would rather use the spark plug gapping trick instead

[KRNAGE]

Nepharius, I have a Dashhawk if you want to catch up and read the CEL code.
I may know the same Daz and if so, yeah I never saw any CEL's on his car.

Im running no cat on my downpipe and have no CEL - its been on for a couple of months now but it uses an extender on the o2 sensor

anyway let me know I know how frustrating it is to have a CEL and not know what its from

[Nepharius]

Yeah I'd be interested in checking out to make sure it's what I think it is before I go stuffing around with the 02 sensors. The daz I'm talking about is D-Mag on Ozmazda, he said after ~5000km and continuously clearing the error the ECU got used to it.
If I do have to do this spacing trick can it be done with the dump on the car? What exactly needs doing I want to be able to describe it to an exhaust place properly so they don't do something completely different.

[2XS]

You can also buy the spacer.



Fitted: looks like this

[KRNAGE]

yeap same Daz I know, have you checked your O2 sensor wire isnt touching the pipe and melted? I know that happened to Daz so he had wrapped up his sensor with high temp wrap

lets figure a time to meet up and we can connect my DH up