X-Pipe installed, now issues

thomas91169

I'd donkey punch my sister.
Aug 19, 2005
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Modesto, CA
Just installed a Mac O/R Xpipe w/o cats on my 02 GT. Installed the o2 sensor eliminators. drove about 10 miles and now the SES(or CEL) came on.

would a leak between the he and downtubes cause the cel to come on? i know all the bolts were as tight as possible but im just checking anyways.
 
You should be able to pick out an exhaust leak.

It will sound like a fluttering or ticking, hissing... along those lines. Id go to Autozone or Advance and get the codes checked for free.

The passenger side flange gasket (where the manifold meets the x pipe) has a real tendency to destroy that gasket. It usually gets loud when its shot.
 
Get a scanner hooked up and get a detailed description of the code. It might not even be anything to do with the exhaust. My first mid-pipe swap I accidently broke my driver side upstream O2...not sure how, but I did. So, get the code checked.
 
Come on guys, this question is old as the hills. When you put on the pipe with no cats, it throws the sensors off, and they are measuring a less clean exhaust now without the cats. What you need to do is get a set of MIL (malfunction indicator light) eliminators, which will turn the lights off. There is nothing wrong with the car, but the sensors dont know that, this happens anytime you put on and off road pipe
 
Come on guys, this question is old as the hills. When you put on the pipe with no cats, it throws the sensors off, and they are measuring a less clean exhaust now without the cats. What you need to do is get a set of MIL (malfunction indicator light) eliminators, which will turn the lights off. There is nothing wrong with the car, but the sensors dont know that, this happens anytime you put on and off road pipe

he already has the eliminators. Which type of eliminators do you have. The ones you just plug in? Which ever ones I would check to make sure they are on right. I don't think a leak would cause the light to come on. I have a leak in the same spot that you mentioned and I have no lights on.
 
25 bucks shipped!

oh and one had to be slightly modified. the connectors on one side are different from the other side, they have little alignment "nubbies" that each side has a different pattern, and i got two of the same (drivers side) so i just shaved them off of one for the pass side.

you dont even need to connect the downstream o2's with the MIL turned on in the tune correct? i just installed the tune and modified it and whatnot, no more cel!
 
I don't know much about how your guy's EEC work so this is more of a question than anything else....


By running the MIL eliminators, aren't you still passing data from the 02 sensors to the EEC? I understand that they're supposed to turn the light off but don't they also still allow measurement of the exhaust so that the EEC can make adjustments in the air/fuel mixture?

Part 2:

If you turn off the 02 sensors using the Diablo, then what will the EEC use to make adjustments to fuel tables?
 
the downstream o2's are the only ones affected. their job is basically to let the ecu know if the catalytics are doing their job or not. if you take out the cats, the ecu sees they are not working and pops up a code. the upstream (closest to the manifold) are the ones that take the readings and base the fuel maps on, those you do not **** with, but since they come before the cats, adding a cat-less midpipe is of no concern to them. you are only turning off the ecu's ability to register a code due to the downstream o2's saying theyre not getting a reading, basically disabling the downstream o2's.

the MIL's i have are plug type, and they connect between the o2's and the stock plug. im assuming they *do* pass some sort of signal, maybe they make the same signal a proper reading from a catalytic is supposed to look like :shrug: but they did not work for me (which is why i had to stick my diablo back into the game) so i dont know.

http://www.dallasmustang.com/page/products.php?product=9074
those are what i have.
 
Got it, thanks. Didn't mean to detract from the original thread but thought it might have been relavant. I didn't realize there were multiple sensors per exhaust bank. Makes sense now. hehe