I currently have a 00 Civic DX Auto Road Warrior (DD). She has 260+k on the clock and runs like a champ with the exception of throwing a CEL for a bad cat.

**skip to other (**) for the short version

I feel pretty sure the cat is clogged due to having a previous misfire problem (dumping unburned fuel into the exhaust). The previous owner did the CFK bypass trick on the car (I didn't know) and when I went to change the timing belt, I replaced the bad CFK sensor. This caused the CEL that I had for about a month. Took it to dealership, they couldn't find the problem, claimed the car was running fine (no TRUE misfire), but it was still throwing the code. So, I drove it for a month or 2 before taking it back. Then, they found the splices by the ECU. So, I d/c those connections, and no more MISFIRE CEL, but there was a new one for the second O2 sensor. I deduce that it WAS misfiring, and wasted the cat.

I am looking into replacing a bad cat, and the type that are on the DX/LX cars from the factory are much more expensive and more prone to cracking than the type on the EX cars.

**Sorry for the long intro. If I got a manifold & cat from an EX (VTEC) car, would it bolt up in the stock position on my DX car, or would the exhaust need further modification? I'd heard from some other ppl that all I'd need to do is to replace the mani & cat with ones from a EX model, run an O2 sensor extension, and all would be well. Can anyone with first hand exp verify/deny this?

 

No, you would need to cut a portion of the exaust pipe on your car to fit the EX cat.

 

you would need to modify your existing piping, as the ex cat has a 3 bolt flange at the back, you have a 2 bolt flange there.

 

Thanks for the input, Guys.

 

i was asking something similar, and found that the DX hatch, and DX coupe/sedan had the same part number for the midpipes.

so you can probably use the EX coupe midpipe and bolt straight to the cat and muffler no problem.

it seems like its the muffler in these cars that makes up for the length