91 Acura Integra - High NOx - Failed emissions test

91 Acura Integra - High NOx - Failed emissions test - NJ

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sabys@hotmail.com - 09 Aug 2006 21:15 GMT

My 91 acura Integra LS failed the emission test a second time for high
NOx. Could the gurus please provide some input on what I should be
checking? Here are the details.

Test 1:
NOx - 1984
HC - 91
CO% - .34
CO2% - 14.3
O2% - .6

After this test, my mechanic replaced the Catalytic convertor. The
second test results were:
Test 2:
NOx - 1367
HC - 10
CO% - 0.00
CO2% - 13.2
O2% - .9

So, the NOx did drop but not enough to pass the test. (The pass level
of NOx in NJ is 1088)

Any recommendations on what could be the big culprit?

Thanks in advance.

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TeGGeR® - 09 Aug 2006 23:07 GMT

> My 91 acura Integra LS failed the emission test a second time for high
> NOx. Could the gurus please provide some input on what I should be
[quoted text clipped - 22 lines]
>
> Thanks in advance.

If you have an automatic, check the EGR system.

Check base ignition timing. With the Service Check Connector shorted, the
timing mark on the timing belt cover should be in the middle of the group
of three on the crank pulley.

I'm wondering if the reduction side of your "new" cat is defective. Your
CO2 reading is WAY too low. It should be well over 15%.

By the way, NJ is *extremely* generous with their limits. Where I live,
they're postively totalitarian about it:
http://www.tegger.com/hondafaq/misc/91_integra_emissions.html

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TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

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jim beam - 12 Aug 2006 15:52 GMT

>> My 91 acura Integra LS failed the emission test a second time for high
>> NOx. Could the gurus please provide some input on what I should be
[quoted text clipped - 24 lines]
>
> If you have an automatic, check the EGR system.

indeed. the op needs to make sure the ignition is set correctly too. a
lot of non-honda mechanics don't bother with the service connector when
setting timing and it's frequently out.

> Check base ignition timing. With the Service Check Connector shorted, the
> timing mark on the timing belt cover should be in the middle of the group
[quoted text clipped - 6 lines]
> they're postively totalitarian about it:
> http://www.tegger.com/hondafaq/misc/91_integra_emissions.html

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sabys@hotmail.com - 10 Sep 2006 02:54 GMT

Thanks guys. Tegger, jim you were right on the mark. It was the base
ignition timing. I had that adjusted and the NOx dropped to 1013 and
passed the test.

> >> My 91 acura Integra LS failed the emission test a second time for high
> >> NOx. Could the gurus please provide some input on what I should be
[quoted text clipped - 39 lines]
> > they're postively totalitarian about it:
> > http://www.tegger.com/hondafaq/misc/91_integra_emissions.html

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