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Discussion Starter · #1 ·
Can having a hole or a leaky downpipe cause your check engine light to come on. I noticed mine got louder today and then the check engine light went on and stayed on. It might just be a little loose where it hooks up to the precat. Haven't looked at it yet. I'm gonna hook it up to the pocket logger and I'll post the code after I get to school.

Rob R.
 

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Turbo-Less
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Yeah, it probably could... theoretically it could suck in air before the o2 sensor, and mess with the 02 readings...

I was going to suggest to check the codes, you're a step ahead. :)

Let us know!
 

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it could if its an ODB 2 car that has the multiple o2 sensors....
 

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Discussion Starter · #5 ·
My car has 2 O2 sensors. OBD2 cars have 4? Anyway... heh... you guys are prolly gonna laugh at me but oh well. I hooked up the pocket logger and scanned for codes and 11 O2 Sensor came up. I thought this was really weird at 1st because I just replaced my O2 sensors back in July. So I thought about it for a while..... and then it dawned on me. I had a problem with getting the rear O2 outta there because it had been crossthreaded in there. Either from the factory or from the last person to change out the sensors. When I tried to put the new Sensor in after getting the old one out I screwed up the threads on it because the threads on the precat pipe were all messed up. I figured instead of wasting a perfectly good O2 sensor I'd go ahead and cross thread it in there and worry about it when they need to be changed again. Well that sensor fell out today and was giving me O2 readings of the outside air :p This also explains why my car suddenly got "louder". I can't believe I didn't think of that in the 1st place. I was all like "hmmmmmm... The check engine light is on again?? Wonder what it could be this time". Oh well. I'm not sure what to do about it now. Do pre cat elimator pipes have threads in them for the O2 sensors? Or should I just weld it in there or something?

---sorry for the long post :)

Rob R.
 

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Discussion Starter · #6 ·
Oh also I pulled the O2 outta there because I thought it would be better to have no O2 than to have one reading the air outside the car. I'm gonna fix it ASAP but for now I just got the front sensor in. Anyone know how this will affect my A/F ratios? Are 3 of my cylinders gonna be off now?
 

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Your car already knew the data from the o2 sensor was faulty and was ignoring it.

That was the point of the CE light being on :)
 
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