Hi everybody

I have a 00 Civic 2Dr Ex and I have no Cat right now but rather a straight pipe.

The CEL in my car is on and when I took it to have it checked the guy told me it was a problem with the CAT (That's when I found out it didn't have any, I bought it like that).

Now, I am also having problems with my gas mileage. What is the problem? It is way too low!. On average 16 - 17.5 mpg . This got me thinking whetherthe O2 sensor is bad or not.

My questions are:

1- Does the fact that I don't have any CAT can cause the O2 sensor not to work?

2- Does the fact that I don't have a CAT can be causing the car to send a CAT code over the bad O2 sensor code ?? (I wonder this because the guy told me the car wasn't giving a bad O2 code)

3- I am thinking of buying a CAT and installing it but over here they are very expensive (I don't live in the US) and I'm thinking of buying one over the Internet but I'm afraid to buy something that won't turn off the CEL (since it won't be OEM). Could this happen or can I buy just about any CAT and it will take care of the CEL problem?

Take these ones for example:

http://cgi.ebay.com/ebaymotors/HONDA...ayphotohosting

http://cgi.ebay.com/ebaymotors/CATAL...31536506QQrdZ1

http://cgi.ebay.com/ebaymotors/96-97...25246747QQrdZ1


By the way, I am not really trying to gain any power with the CAT I just want it to work properly.


I also have an additional question and that is that I don't see any wires connected to the CAT other than the O2 sensor (judging by other car's photos)so how can the computer tell that there's a problem with it??? Is it the O2 sensor that gives the error code??


Any Thoughts??

Thanks in advance.

 

1. Not really sure if the high flow cat can ruin the sensor or not....

2. Yes, not having a cat will cause you to pull a CEL

3. Those examples you have will NOT cure the CEL, those are basically the same thing, all they are are test pipes. A good high-flow cat will cure your CEL, but sitll be "high flow". Magnaflow and Randoms Technology are two of the only ones i know. If you are going to get a cat, get an actual OEM one, or a Magnaflow/Randoms tech one.

And the other question you have, yes, the sesnor is the thing that tells your ECU that the cat is not working properly, thus giving you the CEL.

 

A CEL of any kind will throw the performance of your car way off.

A straight pipe will cause an O2 sensor to flip because the whole point of the O2 sensor is to make sure your catalytic converter is working properly. If you dont have a catalytic converter...well...common sense.

Those no-name 'high flow cats' off of ebay are just straight pipes. The cheapest high flow cat that I know of that actually works as a cat is made by Magnaflow. It can be had for about 50-75 bucks on ebay.

 

^ or you could get a Magnaflow for $90 from http://www.summitracing.com/and know for a fact that it's really a magnaflow (and to top it off, free shipping! lol I love Summit Racing)

And if you don't have the wires connected, you'll be throwing a CEL since the computer isn't receiving a signal. Also, since your engine is an OBD-II, a straight-pipe will definitely throw a CEL. Either put a cat on, or install an o2 simulator

 

Thanks for your replies, guys

So this one will do the trick??

http://cgi.ebay.com/ebaymotors/ws/eB...292&rd=1,1


Actually, what I was referring to is if the absence of thecat (any cat) could cause the sensor to malfunction, therefore making the car burn a lot more fuel than usual.