E-Test results struggles

[STeveD]

Hanif is struggling to make his beater '96 Civic Auto 1.6L with 360,000km on it pass an E-Test.


Pre-PI E-test: Mar 6/10

2525
HC 73 (75 limit) PASS
CO 0.74 (0.42 limit) FAIL
NO 564 (576 limit) PASS

idle
HC 62 (200 limit) PASS
CO 0.3 (1.00 limit) PASS

Post-PI E-test: May 2/10

2525:
HC 62 (75 limit) PASS
CO 0.49 (0.42 limit) FAIL
NO 778 (576 limit) FAIL

Idle
HC 47 (200 limit) PASS
CO 0.19 (1.00 limit) PASS

So, HC and CO are both down (driving -15%, -34%, idle -24%, -37% respectively), NO (+38%) are up - aka it's running leaner now and getting approximately 5-7% better fuel mileage, but I still can't pass an e-test... Hrmpf.

I also checked the ignition timing today and it's set perfectly to 16deg TDC at idle. Plugs are clean, air filter is new, O2 sensor is 6 mths old (oem ngk) and I'm running 5K old 0W20 AMS.


Thoughts? I found this Toyota document that still seems to indicate incomplete burn in one or more cylinders...

http://www.autoshop101.com/forms/h56.pdf

Just looking at the charts, for CO and NOX to be high together, it looks like he might still be on the rich side at higher RPM. Like he is not getting complete burn.



Generally speaking, on fuel injected vehicles, high CO means too much fuel is being delivered to the engine for the amount of air entering the intake manifold.



Anything which causes combustion temperatures to rise will auso cause NOx emissions to rise. Misfire can also cause NOx emissions to rise because of the increase in oxygen that it causes in the catalytic converter feed gas.

[srprs-t]

gas line antifreeze helps, small bottle in the tank!

[Cavemanrjc]

HC= misfire indicator
CO= rich / lean indicator
NOx= high cyl temps

That looks like a typical Honda failure

Those numbers tend to be caused by a slow o2 sensor, and high timing.
did you jump the timing connector behind glove box when you checked timing?

The hotter the cat the better
check cooling system for poor airflow
if you know the dude running the test have him run it in second gear and have the heat on hi on the floor

have you had a pre and post done on the cat?
it could be bad

but shy of scoping the O2, i would lean towards that, and pull a bit of timing out for the test.

[Cavemanrjc]

Quick test for the cat to see if its doing anything
is,
With a pyro gun check the temp at the front and the rear of the cat, the rear should be minimum 100deg f hotter then the front

[JoeT]

High NOX & High HC = Too much timing.
CO drops with high timing, they are inversely proportional.

As Rob indicated, back off on timing about 3 - 5 degrees at 2500 rpm, that should do the trick.