1993 Honda Civic Emissions Problems

1993 HONDA CIVIC
313,250 MILES • 4 CYL • FWD • AUTOMATIC
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RAGTOPJOHNNIE
  • MEMBER
  • 6 POSTS
Hey Now,
My friend has a '93 honda civic 4 cyl. totally stock. He failed his HC ppm and CO % but barely passed the NOx ppm. I helped him change the cat.. It now passed the HC ppm and the CO% but failed the NOx. The part store says this car doesn't have a EGR Valve so I'm at a loss as what to do to get the NOx down.
Can some one help?
Thanks,
John
May 7, 2010 at 4:23 PM
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MMPRINCE4000
  • ✓Experienced Mechanic
  • 8,548 POSTS
They do sell an EGR valve for it. Some Japanese manufacturers made a FEDERAL engine (no EGR) and a CA. engine (with EGR). Do you see an EGR?


https://images.2carpros.com/forum/automotive_pictures/108325_honda_EGR_1.jpg

May 8, 2010 at 2:04 AM
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RAGTOPJOHNNIE
  • MEMBER
  • 6 POSTS
Where on the exaust manifold would I find it? I didn't see one. Also my friends snap-on scanner found (with no check engine light on) a stored code for an over lean condition, fuel pressure regulator. How do you trouble shoot that? The car runs like a top and doesn't knock!
May 8, 2010 at 2:32 AM
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MMPRINCE4000
  • ✓Experienced Mechanic
  • 8,548 POSTS
EGR connects exhaust to intake, some are cast into intake manifold.

There should be an emmissions sticker that says "non EGR" or "EGR equipped".

Lean or rich can cause this problem. You would need to start by checking fuel pressure with mechanical gauge.
May 9, 2010 at 1:00 AM
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