I just recently installed a header back exhuast on my 00 GSR. I replaced the cat with a "High-Flow resonator" (it's not a cat) from Toucan industries and now my check engine light is on. I know this is happening because the 2nd O2 sensor sees that there is no cat, but WHAT DO I DO to get rid of the annoying light.
I am also worried that the VTEC engagemant might be comprimised. I don't really notice a change in power where the old VTEC would switch over. Could the 2nd O2 sensor be keeping me from hitting VTEC?

 

Check your codes. It's likely a 41 (0xygen Sensor) or 67 (I think..) which is a low catalytic convertor efficiency issue (secondary Oxygen Sensor)

The fact that you have no cat on your car may compromise some low end torque from lack of backpressure. I learned this the hard way when I gutted out my cat. Consider looking into a high-flow cat from a reputable manufacturer.

 

I'm thinking about switching over to OBD-1 emissions controls with the skunk2 ecu & adapter harness but i'm not sure it would be worth it. If the check engine light and the pain in the *** 2nd O2 don't affect the power output of the car i'll leave it alone.

I just hate taking a girl out in the car and hearing "hey! why is your check engine light on?!?!" It's a bit imbarrasing!

 

No cat shouldn't effect your vtec. The 2nd o2 on the cat is only there to measure emissions. I have a testpipe and I get the check engine light also, I feel/hear vtec kick in a 4400rpm and noticed a little more power up top, shouldn't worry about it.

 

Heh - there isn't a day I don't leave the house without a CEL staring me in the face. I've gotten a code 74, Random Misfire since 2 weeks after I got the car 2 years ago. It doesn't hurt anything apparently, compression and leakdown tests are good, and performance doesn't seem compromised.

Just tell the girl it's a racecar - and that it HAS to have the CEL to keep running!

 

I heard that if you wrap it in tinfoil it'll go away. I'd have someone here verify that before you do it though.

 

The best/easiest thing to do would just be to convert to OBD1 and chip it. That's what I did, and i'm very pleased w/the results. If you get everything at a decent price, it's worth it. But if you dont wanna go that route, i've also heard that if you wrap the secondary 02 sensor up real good in tin foil, then in electrical tape really well, that it'll fool the ECM and the CEL will go away. I don't know if it really works either, its just what i've heard...

 

Alot of people have, as mentioned above, wrapped tin foil around it and tightened it well. Personally, I wouldnt mess with it. Let that CEL alone until you go OBD 1.

 

Easy fix... put the cat back on. You really don't gain much, if anything, with no cat. That is unless you are boosting or running very high hp, which I'm guessing you are not.

 

o2 Simulator possibly?