2005 toyota tacoma catalytic converter

Hey everyone. So, I got my catalytic converter stolen the other day. I did some research and found out that I have 2 catalytic converters on a single exhaust. They took the second cat which is located towards the back (downstream) after the second O2 sensor. So, I decided to put a straight pipe instead of another cat which I still have the first one upstream.So, now that the straight pipe is installed, I can smell a small amount of rotten eggs inside the car when the window is down. I was wondering if the smell is coming from where they welded the straight pipe and there must be a leak or do I really need the second cat to get rid of that smell. I'm thinking I must have a leak cuz I still have one cat. Lmk what you guys think. Thx in advance

 

definitely a leak at the weld. Sorry about the stolen cat... might consider replacing the cat and doing a cat shield. Just did this on my v6.... cus here in california the only aftermarket CARB approved rear cats are 3000 bucks for the set, i dont even want to know what OEM toyota cats cost.

 

That's total BS you have to do stuff like this. We're toast.

 

Thx for the response. I was thinking the same thing. There must be leak where they didn't weld it good. Not having that second cat gave me more horse power. A big difference. I ordered a cat shield but I won't get it till March.

 

sometimes cars have a pre and post cat for more filtration
and what they really care about for measurement is based on where the O2 sensors are located

for example if there is a main cat high up close to the engine (so it can heat up faster and reach efficiency) with a pre and post O2 sensor on it, but then a secondary little cat way downstream with no sensors, then the car is not gonna notice if that is gone
less cat filtration = more rotten eggs smell

number of ways to find leaking exhaust
burning something smoky to see if it comes out, kind of unnecessary
easier to stuff a rag or something into the tailpipe to create enough blockage to increase pressure in the exhaust while still allowing it to run. Maybe when cold before everything has expanded. Then getting under the truck and spraying soapy water, or watching/listening to find the leak. Soapy water will bubble if a leak pushes air out. Another reason to do that cold. Because if it's hot, then soapy water will evaporate within seconds of touching the hot exhaust and it will be harder to find a leak that way. Just like how you spray soapy water on a tire to find a nail puncture.

 

You can also use a shop-vac on blow for this. Use a rag to seal the vaccum end inside the tailpipe, and use the soapy water method to find the bubbles. Quick and super easy.
ChrisFix even shows his process for this:

 

Run some sea foam through the throttle body and look under there

 

I'm going to guess the smell is the result of putting in the straight pipe and your emissions not working properly.

 

Actually it doesn't smell like rotten eggs. It smells something like propane gas. I can't explain it. But no emission problems. Everything is working fine

 

Yes, the smell is from running one less cat. I went from 2 cats to no cats. I couldn't stand the exhaust fumes so I added a single cat after the Y-pipe. At start up, I smell the fumes more. Once the engine is hot and the cat is hot, the fumes become very faint.

If you want to be completely go away, you'd need to add a 2nd cat like the factory.

 

Good to know! Thx

 

You're on the right track.. but the cats don't "filter" the exhaust. They combine HC (un-burned fuel) and CO (carbon monoxide) to create CO2 (carbon dioxide)

 

Makes stinky into non-stinky