Failed Colorado Emissions

[Get]

I have a 1986 951 without a catalytic converter, Steve R chips from 1999, and Tail waste gate, other than that the car is stock. Today I failed Colorado Emissions Testing with reading HC GPM of 3.6115 and has to be below 3.000. The CO GPM was 23.2540 and has to be below 20.0000 everything else passed. Does any one have any suggestions, I prefer not to have to install a removable Catalytic Converter, but if I have to then I will.

Thanks;
Gary

[Streetcrawler]

Where are you?


What exhaust is on your car?

[Get]

Thanks for the reply, I am in Berthoud just north of Denver. The car has the standard exhaust with the Cat removed.

[mikepellegrini]

You made sure the car was fully warmed up before the test? That's a good 30 minutes or so of freeway driving.

How about your air filter? If it's even somewhat clogged, that can be a problem.

Other than that, you can try octane boosters - which can help.

[nynor]

it is running rich. O2 sensor is the most likely culprit. plugged air filter. leaky injector(s). there are other possibilities, but that is where i'd start. air filter first, because you can check it in 5 minutes. then the O2 sensor (my bet is on the sensor). then possible injector problems. also, check all those little vacuum hoses for gasoline. if they have gasoline in them, you have a failed FPR/damper.

[Get]

The car does have the original O2 sensor, the injectors were professionally cleaned a few years ago, haven't drive it for two years now. The air cleaner is a KN. Some people have stated that I should used the old chips in the DME. After reading all the post I think I will change the oil, replace the spark plugs, install the old chips, and get a new O2 sensor.

Thank you all for your replies.

[Pete R]

I would also try a lower octane gas for the test. It has a better chance of completely burning that the high octane stuff.

[Streetcrawler]

The chip should not make too much of a difference. My cars is fairly heavily modified and passed fine (with a cat).

E85 burns cleaner. You could probably get away with a gallon or two of that in the tank

[AaronM]

Originally Posted by Pete R

I would also try a lower octane gas for the test. It has a better chance of completely burning that the high octane stuff.

Bull. Utter and complete bull.

While the flame front does move slightly slowed for high-octane gasoline there's not enough difference to be throwing HC readings over the allowable max. The car's running rich, full stop. Lower octane fuel won't do a damn thing other than put him as risk for pre-ignition and detonation under load.

[Pete R]

...well then don't try it.

[wild man]

Originally Posted by mikepellegrini

Other than that, you can try octane boosters - which can help.

Or try one of those special "emissions passing" juices that the auto parts stores sell. Make sure the engine is operating in closed loop mode (using O2 sensor feedback) when taking the test. Looks like your running a tad bit too rich.