I just bought a 1997 Integra (B18B) to get around for now. The previous owner had it smogged just over 3 months ago which was the cut off and it passed at that time (I verified online at smogcheck.ca.go). I went to smog today and it failed terribly at idle. I tried to do some reading on the net but couldn't conclude anything except that it's running rich.

Here are the numbers:

-------------------%CO %O2 | HC (PPM) | CO (%)

TEST - RPM - MEAS - MEAS | MAX - GP - MEAS | MAX - GP - MEAS

IDLE - 779 - 12.0 - 2.7 |100 - 250 - 1075 | 1.00 - 2.50 - 2.16
2500 - 2546 - 14.9 - 0.0 |130 - 280 - 133 | 1.00 - 2.50 - 0.15

The test was one that didn't use the dyno, it was done with the car in park. It required a pre-condition test to keep the car revved at 2500RPM for 3 minutes. The tech said to rule out the car not running hot enough as the problem (I drove for 30 mins prior to testing anyways).

Does anyone know what would cause such a high CO% during idle? The tech was kind enough to mention that the CO% is what I should concentrate on which would lead to lower HC numbers.

Thanks for any advise.

 

Being that it is an OBDII vehicle are you getting codes/check engine light coming on?

Is the ECU chipped? What mod's are on the vehicle?

CO is a tell tale sign of being rich and having bad ignition/poor combustion. This can be a few things. Fortunately your OBDII data can be checked pretty easy.

Things you can check out easy....

Have you looked around the bay for cracked vacuum hoses? Just listen for a high pitched noises too. Pull the vacuum hose to the fuel pressure regulator and see if there is gas in it.
Check for exhaust leaks before the O2 sensor and CAT.
Check your spark plug's

After you check these and if you find nothing unusual then we will have to go further.

 

Stock engine.

Ok... found out the timing was off 4* (yikes!)

So I did cap, rotter, and sparkplugs while getting the timeing done. Wires were still good, so I left them. Left the shop headed to the smog stations again.. noticed idle kept dropping (slight fluctuation).

Smogged... Idle still failed.. HC was about 440 and CO was now good at 0.50%. Both numbers were good for 2500RPM now.

I'm going to clean/replace the Idle control valve now and see if it passes. Anything else I should check? I'll have the shop check for leaks and the FPR for gases.

No engine codes.

Update: I just went to the shop.. guess there's a leak in the ICV.. would that be enough to fail smog though? I'm replacing this later today and will smog tomorrow.