Trailsman1948

What effects fuel mixture at idle? I have a perfectly set up, perfectly running almost newly rebuilt motor with no pre-cat but new main cat and nothing else to effect the emmissions. At 2500 rpm the tailpipe sniffer shows HC=2.0 and CO=0.00 (a zero emmissions car) and at 800 rpm HC=652 and CO=5.25, both 5 times over max allowed in CA, (a gross polluter). What in hell could be that wrong?
Thanks, Peter.

rx7will

iTrader: (6)

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/how-i-fixed-passed-ca-emissions-218346/

If you air control valve is not working properly it will not pass smog. You could ask the smog tech to raise the idle with the gas pedal to see if the readings drop. On my fc it would not pass the idle test without a little help from the gas pedal. The rotary engine runs really rich at idle. You could also try to heat up the cats a lot.

I thought all of California was on the enhanced smog program?

Trailsman1948

Thanks,
I live in the boonies of northern CA and its still the basic test up here. It would pass the enhanced test fine, except when I took it to Sacramento for the enhanced test there they failed on the visual inspection because "the silver intake tubes are not original"!!!!!! I gave up and drove it back to the boonies. But does the 5X over the limit sound way off base to you?
Peter.

DaveW

Could also be air pump not working or hooked up.

Trailsman1948

Yep the airpump is installed and running fine. On Monday I'm taking it into have a precat put on, 3 inch in and out, and then see what the emissions look like. But do you know of any adjustment to the idle richness, or anything that can effect the richness, while it is open loop mode?
Thanks, Peter.

rx7will

iTrader: (6)

I would put the stock stuff back and get an enhanced smog, since you know it will pass. You should check the acv, its in the fsm. It will make everything easier. And make sure that the air from the air pump is actually getting into the converter. If everything works then i would say that your catalytic converter is not efficient enough to pass the idle test. You could try to raise the idle yourself to see if the idle reading gets better. A slow oxygen sensor will cause the idle to be rich, but not as rich as your readings indicated.
I dont think having two cats will make the car pass the idle test.

andrewlevitt257

I have the identical problem on my '85 12a GS. At 2,500 RPM passed the test with flying colors:

%CO2: 11.8
%O2: 3.9
HC(PPM): 12 (MAX: 150)
CO(%): .01 (MAX: 1.2)

Then at idle (756RPM):

%CO2: 9.0
%O2: 0.0
HC(PPM): 538 (MAX: 150)
CO(%): 8.72 (MAX: 1.2)

Another test with idle at 967RPM shows less bad results:

%CO2: 12.9
%O2: 0.1
HC(PPM): 52 (MAX: 150)
CO(%): 3.01 (MAX: 1.2)

So should I just jack the idle up to around 2,000 RPM and cross my fingers? It seems to me like the catalytic converter must be working properly with such low 2,500RPM numbers.

Busted7

Does anyone know the effect of the oil injection on emissions?

Trailsman1948

I put a new cat on. Actually, this cat is a replacement for the pre-cat and the main cat. It pulled my HC's down to 120 and that was without the cat being really hot, I think with a decently hot cat my results will be under 100 easy. For the smog test I might resort to some denatured alcohol as insurance.

DaveW

Is your air pump hooked up and working? At idle the air pump is much more important, since it furnishes a larger % of the O2 needed to oxidize CO & HC's.

Dave

Daniel577h

post up all readings