Hello Honda prelude experts,
I urgently need someone's help/suggestion to fix the emission problem that I'm experiencing with my Honda Prelude 1998 (SH).

I went for the emission test and it didn't pass!!!!

First test result looks like:
================
HC ppm - PASS
CO % - PASS
NO ppm - FAIL Reading 780 (Limit 450)
GAS Cap - PASS
All others - PASS


Second test resultlittle improvement in `NO ppm`)
=============
I replaced with new PVC valve and went for second test.

HC ppm - PASS
CO % - PASS
NO ppm - FAIL Reading 766 (Limit 450)
GAS Cap - PASS
All others - PASS


Third attempt(got worst in `NO ppm`)
============
Before I went for the test, I did following to the car:
- flushed the engine and changed engine oil
- Replaced the distributer cap, plate and wire
- Replace the spark plugs
- Cleaned the EGR valve with Honda Carburetor/Combustion chamber cleaner(
(I test for leak by sucking the air - valve seems to have no leak)
- Used the octane booster before I fill the tank
- Sprayed the Honda Carburetor/Combustion chamber cleaner into the air intake hose and drove about 20 km to the `emission test center`.

What happened ? It FAILED badly.

Result looks like :
HC ppm - PASS
CO % - PASS
NO ppm - FAIL Reading 809 (Limit 450)
GAS Cap - PASS
All other are - PASS


Please help.

 

Clean the EGR and replace the O2 sensors and try again. You could also try the pass-your-emission-test-in-a-bottle from the auto parts store...usually works.

 

I heard that if you run ethanol right before, it checks out fine