My buddies and I decided to gut the cat connected to the exhaust manifold, about 20 miles later the Check Engine light came on. We thought we had the MAF sensor too close to the throttle body cause it was making a funny sound, so we changed it back and reset the computer. Once again about 20 miles later the light came on...The exhaust smells really strong of gas. Obviously the car is running rich. My question is, #1 has anyone else done this or had this problem? If so How did you fix it? Im really concerned because Im not supposed to be doing anything to the car until its paid for (parents orders). Therefore if I take it to they will say that I have voided the warranty by gutting the cat and probably will be dicks about telling me why the lights on...any help would be greatly appreciated

 

i dunno why thats happening but i was just about to do that yesterday but i couldnt get the bolts off, i guess its a good thing i didnt, let me know what u do about it

 

Gutting the cat is never a good way of doing things. Sure it's cheap and easy but you'll experience some hassles, especially if it's the first one since that's where a bulk of the O2 sensing equipment is. If you gutted it really carelessly you could have some of the catalytic material sitting in your exhaust and the car could be running rich since it's sensing the exhaust gasses barreling out of the car faster and thinking more air than is actually being drawn in is being combusted. Just a thought.

 

we disconnected it from the rest of the exhaust to make sure it was all out of the piping, we ran it disconnected from the back cat just to be positive. So, there isnt any material in the exhaust I did think about the o2 sensor confusing the computer, that is what my first idea was, but if thats the case, what can I do about it?

 

What can you do? Either have the code pulled and find out for sure what it is (search for the place on here where you can get that code pulled, forget the name), get an OEM cat (that won't look suspicious ) and connect that to see if it makes the light go away and/or pray that you're not running super rich. That first cat is a meanie and they really didn't want you playing with it to much. You could also check the gaskets around the cat and see maybe if you're leaking. That does it for my options.

 

pjal84 is correct.

All cali spec, OBD2 systems are very tough to trick.

When the 2nd O2 sensor reads too much exhaust gas flowing out of the cat, it will tell the 1st O2 sensor to compensate accordingly to its conservative, factory setting. It will dump more fuel; if that doesn't correct the problem, the CE light will appear along with ticking valves like late model escorts (fuel burning a bit above the valve stems) and smells like gasoline out of the exhaust.

If you put a O2 simulator, it will cure it on the 2nd O2 sensor. If you have a problem under warranty, the mechanic will read the faulty O2 reading and be wary to fix anything. 600 bucks job for a new cat w/o tax.

 

are there any long term problems if I just let it keep going with the light on?

 

it all depends, it might just go away. but you should at least get it scanned, you don't know where its coming from and you might cause more problems

 

Yes, the CE light from a gutted or faulty cat from the 2nd O2 reading will retard performance of the engine so bad . . . burn up piston head (or warp its head) and damage valves from extreme richness. It might get so hot to crack your cyl head or blow up your gasket.

Either way, a dealer mechanic will get a lot of money for taking the motor apart for replacement.

 

The chances are the cat caused it on the 2nd O2 sensor.

How did I know . . . I had this problem long ago w/ my topspeed mid-pipe. CE light within the 40 mile mark. Now, I have my O2 simulator on now . . . after fixing my switches, that mod will be on my car again.

 

two questions, what is a MIL eliminator, and would that work? and what is an o2 simulator?

 

I do believe they are basically the same thing.


An O2 simulator will be attached to the wiring on the 2nd O2 sensor, creating a constant volt reading. Never a CE light, but the dealer mechanic will pull the code as faulty O2 sensor (despite not showing a CE light).

 

any ideas as to where I could get one?

 

The parts can be bought from radio shack . . . www.miragetuner.com . . . it's on our site. Find how-to and elec stuff.

The only thing if the lancer shares the same voltage reading as the mirage.

 

should I do this to the first or second o2 sensor, since I gutted the first cat

one more thing, is there anyway to lean out the motor...since it is running so freakin rich?