Bad oxygen sensor ?

[Romans, Mark]

Headers might me making run lean too!
  ----- Original Message ----- 
  From: Edmond 
  To: gmecm at diy-efi.org 
  Sent: Wednesday, November 08, 2000 9:59 AM
  Subject: Bad oxygen sensor ?


  I did several 1/4 mile runs after I installed my Edelbrock headers and brand new o2 sensor. First and second gear are nice smooth 900mV range ramps. Once it hits third gear is starts descending rapidly to about 400mV and stays down until I let off the throtle. I wish I was at home so I can show you the exact Diacom graph. I tried giving it more fuel (almost 95 in the VE tables) between 90-100 KPA but it still does this. The engine runs fairly well at WOT, but I cant really tune it w/out gettting some accurate info from the sensor. My old 80K mile o2 sensor in the exhaust manifolds didnt do this at all. Could this indicate a bad sensor ? I should mention at idle it goes from 40-50 to 800-900 almost every 1/2 second. It does this at light cruise too. Maybe it's time for a heated sensor ? Still downt explain the WOT weirdness though since it should be nice and hot.



  p.s. I know Bruce already answered this on the thirdgen.org message board, but I wanted some more opinions :)
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