Huge Exhaust Problems...please Help
Huge Exhaust Problems...please Help ok, my check engine light has been on for some time now...took it to autozone, said bad o2 sensor....got a new one and when we went to put it on ,,the only place i saw was on the drvr side near the manifold...went ahead replaced the drvr side....well its still showing the code for a bad o2 sensor up front, one before the cat...so i ordered another one and was gonna replace the pass side when it came in......
Ok, now the fun part....today i went to get my cutout welded on and noticed that there are no cats on the exhaust....i also noticed that the only o2 sensor that was hooked up was the one on the drvr side before the cat (the one i replaced) someone has put in new pipe starting at the manifold and there is not even holes where the other o2 sensors go..........So , i have one o2 sensor hooked up, the drvr side front...........what do i need to do...whats the easiest fix...the car is idiling fine and i cant really tell that anything is wrong...
Ok, now the fun part....today i went to get my cutout welded on and noticed that there are no cats on the exhaust....i also noticed that the only o2 sensor that was hooked up was the one on the drvr side before the cat (the one i replaced) someone has put in new pipe starting at the manifold and there is not even holes where the other o2 sensors go..........So , i have one o2 sensor hooked up, the drvr side front...........what do i need to do...whats the easiest fix...the car is idiling fine and i cant really tell that anything is wrong...
If you dont have the front passenger side o2 hooked up you need to get that fixed, hows the car running btw? Easiest way to do that while giving some hp gains would be headers.
..` can i just get a bung put in on the pass side and then hook up the o2 sensor.....what about the o2 sensors behind the cat,,,what needs to be done about them...the hookups are there but there are no o2 sensors or bungs in the pipe for them..........why would someone do this..
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Joined: Dec 2001
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From: Jacksonville, FL
Make a short sig for your car so people will be able to help easier. 
If the cats were deleted, previous owner probably just had the codes turned of for the rear 02 codes. If the light just came on for a precat sensor the code will tell you which side it is - you probably have a bad passenger side precat sensor? - get the code(s) read again and post'em.
If the cats were deleted, previous owner probably just had the codes turned of for the rear 02 codes. If the light just came on for a precat sensor the code will tell you which side it is - you probably have a bad passenger side precat sensor? - get the code(s) read again and post'em. o2 There is not even a hole for the o2 sensor to go in on the passenger side....the hook up for the o2 sensor is there but there is no o2 sensor and not even a place to put it in on the pipe..................there is a hole for the drvr side, and there is a new o2 sensor on that side,,,,,,,,,then once down the pipe there is not a cat, and the o2 sensors behind the cat are not hooked up....not even a hole in the pipe for those either
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.. also, i got the code from auto zone....they could not tell me which side, just the o2 sensor before the cat is all they could tell me,,,,,,,,,which im sure its the pass side since there is not even a place to put one and i can see that the hook up has no o2 sensor attached to it
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.. Is the pass side o2 sensor bung on the manifold or on the actual pipe after the manifold...........................also,,,if i got lt headers what all would i have to do.........will the front o2 sensors hook into them..........and what about the back o2 sensors,,,,what do i do with them
. do u run cats with the lt's.............also,,,does the o2 sensor before the cat go into the manifold.......or does it plug into the pipe after the manifold
Last edited by bow125106; Dec 14, 2006 at 08:27 AM.
You can easily run cats with LTs. You want Magnaflow 3" dia ceramic (or metal if you can afford them) cats and then connect to the rest of your exhuast, since most LT's have a collector dia of 3".
You know adding LT's to your setup will provide a place for both 02 sensors, but that's kind of bypassing the original problem of why there isn't a place for them in the first place. However it's never a bad idea to go with LT's...but if you just want to fix your current exhaust, take it to a good exhaust shop and they can make a place for your other 02 sensor (drill and tap a hole for it...), the same as the other side. What are your mods? If you have a factory exhaust you probably don't want to go through the hassle of getting cats for it, until you go LT's, unless you need them for emissions, but I would go with LT's at the same time.
Usually the 02 bung for LT's is in the collector, for factory setups I believe it's NOT in the manifold itself but in the pipe after the manifold however someone else correct me if that's not correct.
You know adding LT's to your setup will provide a place for both 02 sensors, but that's kind of bypassing the original problem of why there isn't a place for them in the first place. However it's never a bad idea to go with LT's...but if you just want to fix your current exhaust, take it to a good exhaust shop and they can make a place for your other 02 sensor (drill and tap a hole for it...), the same as the other side. What are your mods? If you have a factory exhaust you probably don't want to go through the hassle of getting cats for it, until you go LT's, unless you need them for emissions, but I would go with LT's at the same time.
Usually the 02 bung for LT's is in the collector, for factory setups I believe it's NOT in the manifold itself but in the pipe after the manifold however someone else correct me if that's not correct.
.. the car is stock and i dont have the money at the moment for any upgrades.....do u think i can just put a bung on the pass side, hook up the o2 sensor and be good..........will the rear o2 sensors not being there, and the cats not being there, hurt anything.......the only code it showed was the front o2 sensor
Usually when the car has a bad 02 sensor, it runs really lean or really rich...that usually is bad for the cats but since you don't have cats it should be alright. If it's running pig rich your mileage is going to go down, so either way I would get it fixed as soon as possible to be safe.
It still might throw a code for rear 02 sensor after you get the front one installed, and it may run rich again with no cats installed, so you'll need a tune ($400-500) to correct it. Not necessary probably because theoretically that's why you have 02 sensors so it can correct for the right air/fuel ratio, but it's not exact.
Best bet for the least amount of money is have your exhaust guy put in the front 02 sensor, then see how it is. Check it out at that point and make a determination from there.
It still might throw a code for rear 02 sensor after you get the front one installed, and it may run rich again with no cats installed, so you'll need a tune ($400-500) to correct it. Not necessary probably because theoretically that's why you have 02 sensors so it can correct for the right air/fuel ratio, but it's not exact.
Best bet for the least amount of money is have your exhaust guy put in the front 02 sensor, then see how it is. Check it out at that point and make a determination from there.