O2 elimination

**Lithium** · 03-31-2011, 05:02 PM

I was wondering what everyone has done with oxygen sensor configuration with no cat. I want to keep my O2's working properly but want to eliminate my cat as well. Suggestions would be much appreciated, thanks guys.

**dpartinvr4** · 03-31-2011, 05:11 PM

fed spec cars it doesn't matter, I have no cats, and there were are only the "post turbo"
O2's on it.

**dbest671** · 03-31-2011, 05:20 PM

Even if you have the secondary 02 sensors (91-95 Cali spec or OBDII), they are ONLY for emissions purposes. They in NO way effect performance/efficiency of the engine. There are really only three options a) deal with the CEL light b) try the O2 extenders {anti-foul spark plug extenders} or c) get 3sx O2 simulators.

I have tried option b on the Spyder and it didn't work, I still got the CEL. So I bought the 3sx O2 simulators, just haven't installed them yet.

**Lithium** · 03-31-2011, 06:49 PM

I dont want the car to go into safe mode so I will be going with the sims. thanks a lot

**dbest671** · 03-31-2011, 07:10 PM

Originally Posted by Lithium

I dont want the car to go into safe mode so I will be going with the sims. thanks a lot

The o2 simulators are for the secondary o2 sensors (after the precats), they don't replace the primaries you need those. And the primaries wouldn't be effected if you don't have any cats (like dpartinvr4 said). And the car doesn't go into safe mode for the secondary o2 are fubared... at least mine didn't.

**Lithium** · 03-31-2011, 08:32 PM

Originally Posted by dbest671

The o2 simulators are for the secondary o2 sensors (after the precats), they don't replace the primaries you need those. And the primaries wouldn't be effected if you don't have any cats (like dpartinvr4 said). And the car doesn't go into safe mode for the secondary o2 are fubared... at least mine didn't.

I thought every time the CEL was on the car went into limp mode.

**dbest671** · 03-31-2011, 08:41 PM

Originally Posted by Lithium

I thought every time the CEL was on the car went into limp mode.

That is a good question actually. I don't know why the car would go into limp mode since the secondary o2 sensors do nothing except monitor the emission efficiency.

**stealthee** · 03-31-2011, 08:45 PM

Originally Posted by Lithium

I thought every time the CEL was on the car went into limp mode.

Not the case. I had an EGR CEL and the car ran no different than before.

There is no o2 after the main cat anyway.

**RL7** · 04-01-2011, 02:17 PM

Some cars don't really care if the O2's are absent for whatever reason. Mine doesn't, no CEL (for the O2s at least). Another option is to get a wideband with an additional 0-1V output and run it to the ecu. My PLX can do this, but I choose not to do it. If you check one of the service manuals, the ecu only goes into limp mode for a few specific CELs. I think mitsubishi's term is "fail safe" condition. I think without O2's the car just defaults to open loop maps, which will probably be on the safe side (richer).

If you are just removing cats, there isn't much of a need to do anything with the O2s.

**Lithium** · 04-01-2011, 04:03 PM

Originally Posted by RL7

Some cars don't really care if the O2's are absent for whatever reason. Mine doesn't, no CEL (for the O2s at least). Another option is to get a wideband with an additional 0-1V output and run it to the ecu. My PLX can do this, but I choose not to do it. If you check one of the service manuals, the ecu only goes into limp mode for a few specific CELs. I think mitsubishi's term is "fail safe" condition. I think without O2's the car just defaults to open loop maps, which will probably be on the safe side (richer).

If you are just removing cats, there isn't much of a need to do anything with the O2s.

I will have to check and see if my wideband has an aux output. If possible I would rather do that.