Emissions Failure - NOx
#1
Emissions Failure - NOx
I just picked up a 1994 Firebird with a 3.4l. The car had a DTC 76 which is EGR when I bought it. I replaced the EGR with a junkyard unit, the code went away so I proceeded to take it for an emissions check. It failed the first time in HC 2.50 with a .80 limit and NOx with 3.50 with a 2.50 limit, CO passed with 9.00, 15.00 limit. Long story short, cat was gutted, replaced it with a Walker unit, HC passed with .73, same .80 limit and CO registered 0.00. NOx failed even worse the second attempt, 4.50 with the 2.50 limit. Where should I go from here? The plugs looked a good tan and the car seems to run good. Other than that, no other parts were checked or changed. Thanks for any input.
#4
I'm sure the o2s are original @ 136k. I ended up putting a new EGR valve on and that did the trick, dropped the reading down to 2.5ish. The HC and NOx are still on the high side for a stock 3.4l imo, but this will have to do. Thanks for the input.
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sleeperZ96BT
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09-09-2015 08:28 AM