Question about exhaust system for 2005 Taco

Fellas,
Need some help. I found a great 2005 TRD off-road Tacoma that I want to buy. The person who owned it changed the exhaust system to a dual pipe system and added some noise-makers and what not. The system was apparently illegal in MO, where the truck is.

He took it to a muffler shop today and claims it is fixed. I'm not a mechanic and have no idea if the new exhaust system is back to Toyota factory specs, or at least good enough that I can relax that it is not causing problems.

There is two exhaust pipes coming from the engine. On the drivers side, the pipe goes to a catalytic converter with an o2 sensor above and below. From the passenger side, the pipe goes to a catalytic converter with no apparent 02 sensors visible in the photos he sent me. The pipe then goes to a y pipe connecting the exhaust pipe from the drivers side to the single pipe coming from the passenger's side and on to the muffler and out behind the truck on the passenger's side.

1) Is this how it would have come from Toyota? 2) Should the catalytic onverter on the passenger side have 02 sensors above and below (it doesn't have any that I can see) or does only the drivers side exhaust have 02 sensors? Should there even be 2 catalytic converters or should the cat converter be downstream of the y pipe?

I have some photos I can email if anyone is willing to look at them for me. I just dont have any other way of knowing if this truck's exhaust system is a deal-breaker on buying an otherwise great truck. Help! Doug DIllingham Ohio City, CO

 

Post up the photos.

The way you describe it sounds like the OEM routing, exhaust manifolds on both sides of the engine (drivers side goes under the transfer case if you're 4x4) coupling to a Y, then down to the muffler, then over the rear axle and then a 90* bend to the tailpipe behind the rear passenger side tire. I know both the driver and passenger pipes that come from the manifold have cats, I'm not sure about how many O2 sensors each has. I'll have to check on my own truck. I'll chime back in after work.

 

Yeah, I guess if the 2005 Taco has two exhaust manifolds, the million dollar question for me is is the Catalytic Converter on the passenger side supposed to have 02 sensors above and below? Only the driver's side Catalytic Converter appears to have O2 sensors in the photos. I need a mechanics input but I'm in CO and the truck is in MO. Anyone know the answer to this conundrum? Doug

 

Don't know about Taco's, but my Ford had two converters on the Y-pipe. But I'm pretty sure you need O2 sensors on both pipes. Not sure why you'd have two on one, and none on the other, unless one is a dummy pipe, and the other without the sensors is gutted or something. Sounds pretty fishy to me.

 

So does anyone know for sure whether a stock 2005 Taco 4x4 TRD should have one or two exhaust manifolds? How many Catalytic Converters should it have? Doug Dillingham Ohio City, CO.

 

4 converters (I have 05 Taco v6). two converters for each cylinder bank. 4 o2 sensors. Two o2 sensors before the first set of cats, another set of o2 sensors after the first set of cats.