Drive Clean Help

I'm trying to sell a 1986 Honda Civic Wagon. It only has 160k on the clock
and is kept in very good condition. The body is rusted, but that's beside
the point.

It passed a drive clean test in Ontario back in 2001 without problems.
However, this time it failed. Here are the results.


ASM2525 Test Curb Idle Test
limit reading result limit reading result
HC PPM 135 109 pass 300 105 pass
CO% 0.76 0.28 pass 1.50 0.18 pass
NO ppm 1554 2394 fail N/A N/A N/A
RPM 1794 Valid RPM 1051 Valid
Dilution 14.8 Valid Dilution 14.6 Valid

Is there some way to fix the NO problem without buying a cat for the car?

-Kim

 

No guarantee it will pass, but make sure the EGR system is funtioning. A
malfunctioning one can cause the problem you describe.

 

Does it have EGR which could be malfunctioning? Other than that, high NOx
is basically caused by too lean/hot a fuel burn. It doesn't look like you
could get away with richening of the mixture much without violating HC.
You could try backing off the ignition timing so it's at the low end,
slightly retarded, of the range. Also check the carb throttle shaft
bushings - at that age their probably a bit worn and letting air past and
leaning the mixture a touch. Maybe try putting some grease and heavyish
engine oil on them just before the test.

Do you have oxygenated fuel there? I wonder if that could affect this??...
anybody know?

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??