I'm having some trouble getting my d16z6 through emission test here in Europe.
The carbon monoxide emitted, must not exceed 0,5 vol % at idle or 3000rpm.

After the first time I failed, I install a new catalytic converter, new o2 sensor and air filter.
I've also run some Valvoline additive through it.

Now the car passes at idle but not at 3000rpm
With a reading of 1.0 vol %.

The motor is otherwise stock with good 190psi compression on all cylinders.
I do have a Hks exhaust system and a aftermarket header.

Can anyone help me, what to do next?
It would be much appreciated

 

New spark plugs, wires and cap, clean the throttlebody/iac with carb cleaner (take it off the intake and remove the IAC and clean the heck out of it) verify no vacuum leaks, adjust valves if you havent in a while.
hook up a scanner and see if you have any pending codes, repair if needed.
Good luck

 

Pulled the plugs!
The pistons looks a little wet.
Also there were some oil residue behind gasket on the sparkplugs. Tho the walls down to the spark plugs were dry as a bone. So it's not the valve cover that's leaking. Most likely the gasket being compressed too much, and is no longer working.

 

Looked for vacuum leaks today.
Found this line was missing clamps and had a small tear.
Is it the vacuum for the return line?
If so, maybe that's why its running pig rich.

 

[QUOTE=D-lish;52882369]Looked for vacuum leaks today.
Found this line was missing clamps and had a small tear.
Is it the vacuum for the return line?
If so, maybe that's why its running pig rich.



Thats the vac line for the fuel pressure regulator., If it was leaking, you would have a highish idle, and maybe a check engine light.
If the car still fails smog after a good tuneup. Maybe try taking it out on the highway and run the guts out of it. Get it up to operating temp in your driveway (cooling fan cycles twice) and then take it to the freeway and FLOOR IT, let the transmission shift at the high RPM (automatic) if manual shift at the red line. Sometimes the cat gets slightly fouled up when the car has not had a tuneup in a while and flooring it while driving blows the crud out.

 

also, when was the last time you changed the air filter

 

Could you please advise me what the problem could be: I am sending the two sheets with the indicators: No smoke comes out of the exhaust When increasing the engine speed it smells of exhaust gases. The car is: Honda Civic LX 1999. Engine- 1.6 l, mileage 213764

 

My '97 Del Sol VTEC is starting to get close to failing and I have a similar looking spark plug on the #3 cylinder. My other symptoms are a very rare (twice in a couple of years) check engine light showing a misfire on the #3 cylinder (after I run it hard in VTEC). My planned fix is to replace the valve stem seals. I believe oil is getting by them and fouling up the plug / causing a misfire. Burning oil in turn, fouls up the catalytic converter. Just wanted to throw that out there because it kind of sounds similar to your issue. The loss of power described by your smog tech, indicates that the onset is at VTEC activation. This could be the same or separate issue.

On the other hand, I don't think burning oil causes high NOx readings, so take all this with a grain of salt.