Hi im new to these forums I came here to get a question answered.
My check engine light on my 98 civic just came on and I cant figure out whats wrong. I recently installed a test pipe about a month ago, I dont know if this might of caused it, but why would the light come on now. Im not sure whats wrong plz help!

 

ur car is obd2, u have a second o2 sensor on ur stock cat, using the test pipe eliminated it, hence ur cel.

 

read.

https://www.honda-acura.net/forums/s...d.php?t=125370

http://www.c-speedracing.com/faq/03.php
http://www.c-speedracing.com/faq/06.php
http://www.c-speedracing.com/faq/05.php

 

I agree, did you put a bung in the new test pipe for your secondary O2? Read the aforementioned links to provide us with the CEL code so we know exactly what your computer thinks is wrong.

 

Even if there is a bung for the o2, youre still going to throw a cel for cat failure.
You'll most likely need an o2 simulator.

...and I hope you get caught running w/o a cat

 

I think im going to put the cat back on. The test pipe gave me minimal Hp gains and made my exhaust sound like crap. My exhaust lost all its bass, its sounds like a super raspy rice car now.

When I put the cat back on you think my engine will return to normal?

 

If that's what the cel is for, yes. Just replace it and pull the neg cable off the battery to reset the ecu.
If you still get a cel, then you need to recheck it and fix whatever is wrong.

 

oK my freind unplugged my battery and the check engine light went away. Are you sure theres 2 o2 sensores on my stock cat? theres only one hole, and my test pipe has an o2 sensor.

 

dude.... :uhhok:

For future instances that your CEL comes on, don't just reset it and think you've magically fixed the problem. You have been provided the proper procedure for ascertaining what exactly your ECU is saying is wrong via the CEL flash count. Find out what the problem is so it can be properly addressed. GAH!

AND, your car is a '98; therefore, it has 2 O2 sensors.

 

Thx everybody. I will check the CEL count next time the light comes on if it does.