1994 Toyota Pickup fail smog

1994 TOYOTA PICKUP
268,000 MILES • 4 CYL • 2WD • AUTOMATIC
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WMEJIA
  • MEMBER
  • 1 POST
my pick up failed smog for high nox. egr is working fine. cat was replaced two years ago. compression is around 150 to 155. i am thinking maybe timing chain is to loose. burns no oil or no oil leaks. at 25 mph it passed but not at 15 mph. i dont know what else to check.
Oct 4, 2010 at 7:21 AM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
The EGR valve is normally responsible for high Nox if its not opening and will raise the combustion temperature over 2500 F deg, also the catalytic converter and a control system that stays in the open loop mode
Oct 4, 2010 at 8:47 AM
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