View Single Post
  #5  
Old 03-22-2007, 03:01 PM
mhp-mhp mhp-mhp is offline
AF Newbie
Thread starter
 
Join Date: Mar 2007
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Re: Catalytic converter problem? (P420 code)

Update -

Forgot to mention before, this is a 98' Bonne with a 3800k engine.

I finally got my hands on an infrared thermometer and also figured out what I was doing wrong with checking the H02S wiring...didn't have the ignition on.

The temperature at pre-cat is roughly 330 and post-cat is roughly 450. Does anyone know what the "light-off" temperature for this cat. converter should be? (I've read that it can vary from 400 to 600 degrees) Unless the infrared thermometer that I borrowed isn't calibrated correctly, these temps seem rather low to me!

The reason I ask. With the ignition on, I'm getting the appropriate 400mv at both H02 sensors. I start it up and get the appropriate 100mv-900mv (fluctuating) voltage at both sensors. From what I've read, it'll do this until the cat. converter hits it's "light-off" temperature...before that temp, the converter doesn't really do much of anything so the post-cat sensor will mirror the pre-cat.

Unlike a lot of the forums that I've read where people had this same code pop up, my car is actually running a little rough. Idle isn't the greatest (and seems a little lower than usual) and it does seem down on power a little bit.

Any suggestions of what to try next, would be much appreciated!
Reply With Quote