legacycentral bbs

What do those of you with no cat's do for your O2 sensor to prevent the CEL?

I'll be running a catless DP, and don't want the CEL to be on. I'll still have a cat in the midpipe, but I'm having the midpipe flanged so I can swap between a cattless pipe for track days and the cat for daily driving.

Generally, a resistor of the right impedance will cancel-out the signal thrown by the sensor not being present.

Can't say what that'll all do to engine performance when the ECU doesn't see the right information, though.

Lol, damn. Probably can't be to good for performance.

Well, at the very least, the ECU will be a bit confused. In your case, since you're naturally aspirated, it probably won't hurt. . . might even help, actually. If you were running FI, I would be a little more concerned. But the CEL fix is usually a resistor or welding a custom bung on the straight pipe to put the O2 sensor in.

I am FI, lol. See my problem?

Maybe I'll get the cat permanantly installed and just get an 02 sensor bung welded up.

uh...

It's not a concern on our cars because we only have one sensor. The OBD-II systems in 95+ models have a main O2 sensor plus another one that compares the pre and post cat readings to make sure that the convertor is working properly. On our cars there is no such mechanism, so you need not worry.

If you're considering removing the O2 sensor completely, please have your head examined, as it'd be very unwise to do so.

Dave

Thanks Dave. I wasn't sure how many 02 sensors we had. I was hoping there wasn't a pre and post cat. sensor to adjust things.

Deleting my downpipe cat. isn't going to throw a code, will it?

My friend with the 91 turbo has a catless straight pipe with the O2 sensor installed and he still has a CEL

I dont see how changing the cats has any effect on the Check engine light. You sure its an oxygen sensor error?

I wasn't sure. I was driving my friends catless WRX the other day and had the CEL light on because of the no-cats. I wasn't sure if removing the cat on the downpipe would cause a problem or not.

Oh, thats the cat ineficiency code. The WRX has a wideband 02 in front of the second cat and a narrow (like ours) behind it. It can tell when the cat has failed. Removing the cat gives the error. The fix for this costs a couple dollars, why is he driving around like that?

Don't know why he's driving like that. Probably just hasn't gotten around to getting it fixed yet. Didn't seem to harm performance at all.