XPost: sci.electronics.repair, alt.home.repair   
   From: peter@moylan.invalid   
      
   On 24/04/23 04:48, mike wrote:   
   > Only two things have ever set the readiness monitors for me, one of which   
   > was to drive for a few hundred miles at one stretch, and back, which   
   > shouldn't do anything (because I know what a drive cycle entails).   
      
   You seem to be right at the inflection point of the cat efficiency, so   
   almost anything that affects its efficiency will cause your symptoms.   
      
   That means your real question, whether you know it yet or not, is what can   
   increase/decrease the efficiency of a catalytic converter in operation?   
      
   Taking your long drive example, I think that long drive might have heated   
   the cat to the point that maybe that heat temporarily increased its   
   chemical efficiency. Maybe the same thing happens with water in the gas?   
      
   Or, maybe it's not the water in the gas but the fact that the water caused   
   the cylinder to shut off which caused gas to flow over the cat which might   
   have again heated up the cat enough to temporarily increase its efficiency?   
      
   You only threw a little gas onto the cat because you kept resetting the   
   codes so you threw gas on the cat, and then you ran normally hot, and then   
   you again threw gas on the cat, & you repeated that cycle many times over.   
      
   Maybe that heat:cool:heat:cool:heat:cool:heat:cool cycle increased the   
   efficiency of the cat just enough over a threshold to stabilize the system?   
      
   All indicators are that you're on the cusp of catalytic efficiency, where   
   98% of the time or thereabouts you're just efficient enough, but under some   
   conditions that you need to figure out (usually temperature & humidity),   
   you're below efficiency.   
      
   Then the code is set which will reset on its own within three drive cycles.   
   But once you clear the code, you have to wait for cat readiness to be set.   
      
   If you have the time for your next smog, I suggest you do NOT clear the   
   codes (because then you add the second readiness monitor to the mix), but   
   that you let the drive cycle (usually around 50 miles) clear it for you.   
   --   
   Peter Moylan   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)