Contour Enthusiasts Group Archives Forums General Troubleshooting Throttle Hang.... So I'm curious.....

Interestingly, I left my TH fix in while I had emissions tested. Here are the results:

Hydrocarbons: 0.113g (0.276g = standard)
Carbon Monoxide: 1.793g (1.852 = standard)
Carbon Dioxide: 1.765 (no standard given)

So I dunno what to tell you, I still passed emissions.

The emissions test done in the field does not even begin to match the testing that the automakers must go through. We can often get away with modifications that would not stand up to the more rigerous certification testing that the automakers must go through.

When testing for certification, a bag on the exhaust collects all that comes out of the tailpipe during the testing sequence. If the total pollutants (measured in grams) is too high, then the automaker tweeks up the controls a bit tighter to get the level down under legal specs.

The testing in the field only measures the percentage of pollutants coming out of the tailpipe. Depending on the local requirements, the reading may be at idle with no engine load and at 2500 RPM at no load, or it may be under load (on a dyno) at 15 MPH and 25MPH. These testing conditions only measure a very small portion of the cars actual use.

Just a note I notices PaulV mention that he did not have the problem or suspect the problem to be in the Regular DuraTec V6 however I have found that it is since I own one.

More notes on emissions and standards...

1) The worst emissions occur after starting the engine (particularly a cold start), not after letting off the throttle or pressing the clutch pedal. This is largely because the cats take a little while to reach operating temp and don't do anything for you before that time.

2) The 'standards' printed on your inspection report are some % above the maximum allowed emissions for the emissions classification. Besides this absolute limit, there is also a transients limit. This limit basically means that the engine may not emit more than x% more emissions during transients as it does under steady state conditions. Using your HC 'standard' and some SWAG numbers:
Testing HC limit: 0.276g
Emission classification HC limit: 0.250g
Steady-state 19xxMY CDW 2.5L HO MTX HC: 0.150g
Max allowed transient 19xx... HC: 0.180g

In this example, the vehicle must meet standards significantly tighter than the emissions classification limit because the engine's steady state emmissions are so much better than the requirements. Thus, the EPA, in a sense, penalizes the OEMs for good steady-state emissions by requiring more stringent transient emissions controls for a good engine that meets the standard than for another dirtier engine that meets the same standard. Probably more than anyone wanted to hear anyway.