Running Rich after Fabspeed Cat-Bypass Install
 

Need a little help here. I removed the cats and now the car is running really really rich. So bad that my wife is getting sick of the couch smelling like fuel.

My question is how do I fix this and was it running rich before the Cat-Bypasses? I’m debating on if I should put the Cats back on or should the chip be remapped? Pretty sure it an aftermarket chip, I’m going to dig through my stuff tonight to see what kind of paper work I have on the chip.

Car is a 95' with Maxflo mufflers and a Fabspeed Bypasses.

thanks!

Did you damage the O2 sensor while removing it and placing it in the bypass pipe?

My guess is that the O sensor is not functioning correctly. W/o a functioning O sensor the engine does go into a rich, open loop, limp home mode. The connecting wire is the ingress route for the comparison sample air necessary to proper O sensor function(the O sensor develops it's control current from the difference in O content between the exhaust gas and sample air)

As an aside, a cat does clean the air, those of us that are old enough remember when all exhaust smelled like that. However there is also a spectrum, almost clean from a newish tight engine to the rank aroma from an older loose engine. The odor is a combination of burned and unburned oil, and cumbustion byproducts. Neither of my 993 engines has a cat. The new tight 3.8 is fine, the older, loose 3.6 is noxious, even to me, though i've owned worse.

Well Danno you wouldn't have had this problem last month for 2 reasons: 1) you didn't have a wife and 2) you didn't have a couch. My suggestion is to quit driving in the living room!

I agree with Bill ...

Mine started smelling pretty nasty when I put a pre-muffler on it ... initially, it was eye-watering. As it turns out, while I diligently soldered the new universal O2 sensor in place and heat shrinked and silicone taped it all up, I had apparently disconnected the connector in the engine compartment for some reason, and I neglected to re-connect it. After fixing that little brain fart, it still smells quite a bit worse than with the cat, but it's only mildly offensive.