so i got my 3rd camaro, first 2 were late seventys models. this one is a 1994 v6 camaro. i traded a motor cycle for it. car body and interior is awsome. its a 5 speed as well. ok so here is the problem. the guy i bought it from told me the person he bought it from removed the cat. there is a strait pipe there. i was also told that there was a flow master but the last owner had a regular muffler put back on to quiet it up some. well the car runs rough almost as if it had an after market race cam it... like that cam lobe sound, guy tells me that it runs rich because the o2 sensors were removed by previous owner. i got under the car today, sure enough there is no o2 sensor not even a wire hanging were the o2 sensors should be. the car runs and I can drive it up and down my neighborhood, just it runs rough. it is just a little bit smokey too. i do belive it is runing rich possibly because of the o2 sensors? im not too sure i havent been able to hook it up to a code reader yet. im looking for some tech advice. anyone ever delt with an issue like this. and could some one help me to narrow down my wiring i need to find the wires so i could run some new wires and put some o2 sensors back in. i have something that looks like o2 sensors in my exaust manifolds? i am not sure if i should have one before as well as one after the cat. any info would help lots.

 

If you have a working o2 sensor in the manifold, then you shouldnt be running rich becuase of o2's or lack of cat. The second o2 is just there to tell you if your cat is working or not. Id imagine thats whats throwing your code. I dont have a cat on mine, and my car never did any of the things thats you said yours is except throw a code to tell me I dont have a working cat, But you can trick the computer easily.

 

The 94 only uses upstream sensosr ( one on each exhaust manifold); downstream sensors on Camaros started in 96. The lack of upstream O2 sensors will make the engine run in open loop, which means rich mixture and rough running, and poor fuel economy. If the exhaust was altered and there is no place for the sensors, you will need to have bungs welded in and the exhaust drilled to accept the missing sensors.

 

Thanks for the clarification on that. But assuming that what he believes are o2's in his manifolds, are o2's. Then I dont think that this is the problem unless those o2's are bad.

 

Thanks guys I appreciate the info so far. I figured I had down stream o2 sensors. I do have what appear to be o2 sensors in my exhaust manifolds. My car does seem to run rich I belive. It runs kinda crappy. Sounds almost like I have a cam. I'm not sure if the current o2 sensors in the manifolds are bad. How did you trick the computer. Any other info would be helpful. Not sure if anything else might be doing this.

 

o2 simulators i tried to see if anyone has ever made a sim but i cant find to much (there kinda expensive like 70-100

edit: 20 bucks autozone
http://www.autozone.com/autozone/par...mString=search

 

[ It runs kinda crappy. Sounds almost like I have a cam.

check for vacum leaks. that was my problem, it run rich and blows black smoke right? but o2 sensors are only $22 at advanced auto so you might as well replace those to. i noticed a huge difference after i did it.

 

Are you throwing any engine codes? The o2 sensors could be bad as well.

 

I did the non-fouler trick.

http://forums.evolutionm.net/evo-how...ouler-how.html

It moves the o2 out of the stream of exhaust and makes it believe your cat is working. Ive had it on since October and I still havent thrown a code for my cat since.

 

Okay I'm going to do a good lookover today. It idle at 1k rpms. I would assume if it were a acumen leak it would be higher right? It does blow a little smoke has a pretty strong exhaust smell to it. Stronger than a normal running engines exhaust would smell. I haven't been able to get the codes yet. I need to get some one over here with a scanner. Hopefully I can get that accomplished today. Something I also noticed is I seem to be having a little exhaust smoke coming from the engine bay around the manifolds as well. Mabey my manifold gaskets rotted through I'm not sure. Im gonna try to look it all over today. Any more ideas and what is this open loop? Something I did notice is when I mash the gas pedel some and my rpms raise they don't come right back down they kinda slowly come down, this is in neutral of course.