Is it normal that the check engine light is on? When I have changed the straight pipe even though I put back the oxygen sensor?

 

Explain "when I have changed the straight pipe". Do you mean you put a pipe in to bypass the cat?

 

I took out the cat converter and replace a pipe. On the pipe they drilled a hole to put in oxygen sensor. First two hours I drove around didnt have any problem, but later on, check engine light is on, so I dont know if that is normal?Will I hurt my engine?? or anything else??thanks for the reply

 

YO!!!

Maybe you REV your car too much Man!!!
LOL

 

Did they just "drill" a hole for the O2 sensor or did they put an adapter on to raise the sensor out of the exhaust flow and get it farther from the heat? If not, your sensor probably got cooked.

 

they put a adapter on it, but the check engine light is on when I drove couple hours later. Did I damage anything? I still have the original cat converter. Should I change back? But I like the straight pipe tho

 

You need not worry. The worst that will happen is you'll get sick of the light being on. The O2 sensor that mounts in the cat is the secondary O2 sensor. It basically monitors the cat. The light that sensor throws to the ecu doesn't put the car in to a "safe mode". If you had an OBD2 you would get a "deteriorated catalytic converter" error. The primary O2 sensor mounted in the header is the one responsible for adjustment of the air fuel ratio. You'll eventually get used to the light... I did!

 

But is there anyway to bypass the check engine light? Because later on, if my engine really have some problems, I wont know it right. Since the light is always on

 

I don't think you can bypass the CEL as it is only an indicator of something the ECU finds out is wrong. You need to "fool" the computer into thinking that the O2 sensor is giving correct signals. Where there's a will, there's a way. You'll need to find some electronic gizmo that will feed a constant "good" signal through the sensor wire. Beyond that, I don't know. But I seem to remember seeing that some guys with straight pipes don't get the CEL. Can't remember how they did it.

 

thanks