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Emissions Failure, My 1986 nissan 300zx failed emissions

I recently did a motor swap on my 1986 300zx. I failed my first emissions test High speed HC 333 CO 3.76 Low speed HC 406 CO 0.07. I replaced spark plugs and distributor and flushed the fuel system and replaced the fuel filter. I also replaced the O2 sensor. After driving it for about 2-3 weeks I had it retested, failed High speed HC 353 CO 4.16 Low speed HC 738 CO 3.86. What could cause it to get worse instead of better?

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6 Suggested Answers

6ya6ya
  • 2 Answers

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Posted on Jan 02, 2017

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leetamara
  • 702 Answers

SOURCE: my chevy s10 failed emissions

Have your cat. converter checked out. I just had one of these for the same reason in my shop today.

Posted on Jul 09, 2008

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CRTN
  • 716 Answers

SOURCE: Emissions test failure due to high co

wal-mart sells a bottle of stuff that guarantees you'll pass smog. But for me id run a can of injector cleaner through the fuel and clean out the intake. Also id try going to the auto part store and getting a plug that one hotter they will know exactly what you mean. It will help burn more fuel but don't keep them in for too long as they run a little hot. One last thing is hit the catalytic converter with a rubber mallet and start the car. Repeat this until you stop getting black ash out of the exhaust pipe. This will be a sure way to get your Camry to pass smog.

Posted on Jan 27, 2009

  • 1201 Answers

SOURCE: I recently had my 1995

Well, if you have the 6 cylinder, there are 3 02 sensors in that car.
One on front manifold, one on back manifold, and one in the center pipe.You changed one, good idea to change the other 2. That is if you have the 6 cyl.

Posted on Jan 27, 2009

  • 3 Answers

SOURCE: 1994 Mazda Protege 1.8 SOHC failed emissions HELP!

have your EGR system checked . sounds to me like its not working or clogged

Posted on May 03, 2009

  • 15 Answers

SOURCE: Emissions failing with high NOx

You need to check the oxygen sensor. You car may be running lean and therefore giving you increased NOx levels

Posted on May 30, 2009

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