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  #1  
Old 10-18-2006, 08:48 PM
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elninoalex elninoalex is offline
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Emissions question - Carbon Monoxide

I failed my earlier smog test due to a dead plug coil. So I expected to pass when I went back after replacing the coil and some other stuff. HCs went way down like I expected, but the CO went up SEVEN TIMES higher(4.07) than the previous level. I thought it was the cat that took care of the CO. I had a new one installed a month ago. My two previous trips to test: 91 Toyota Previa- 0.17 CO and 84 Chev Suburban- 0.00 CO. So how do you get your CO down?

Stephen
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Old 10-19-2006, 06:20 PM
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Elevated hydrocarbon (HC) emissions usually indicate ignition misfire due to fouled spark plugs or a bad plug. But high HC emissions can also be caused by burned exhaust valves (check compression), lean misfire (check for vacuum leaks, low fuel pressure or dirty injectors), or rich fuel conditions (fuel saturated carburetor floats, excessive fuel pressure, leaky injectors or a dead O2 sensor).

High carbon monoxide (CO) emissions are a telltale sign of a rich fuel mixture. On older carbureted vehicles, fuel-saturated plastic floats, incorrect float settings, leaky power valves and misadjusted chokes are often responsible for the rich mixture. On newer vehicles with feedback fuel controls and fuel injection, leaky injectors, excessive fuel pressure and sluggish or contaminated O2 sensors are all possibilities to investigate.

Harder to diagnose are elevated oxides of nitrogen (NOX) emissions. Causes here may include a defective EGR valve, EGR vacuum solenoid or motor, plugged EGR ports in the manifold, over-advanced ignition timing or engine overheating.

(from: http://www.aa1car.com/library/2000/ic60032.htm)

So I think your fuel regulator may be done. Pull the vacuum hose and see if gas comes out or if the engine idle speed changes since the fuel pressure goes up.
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Old 10-30-2006, 09:33 AM
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elninoalex elninoalex is offline
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Quote:
Originally Posted by svx_commuter
Elevated hydrocarbon (HC) emissions usually indicate ignition misfire due to fouled spark plugs or a bad plug. But high HC emissions can also be caused by burned exhaust valves (check compression), lean misfire (check for vacuum leaks, low fuel pressure or dirty injectors), or rich fuel conditions (fuel saturated carburetor floats, excessive fuel pressure, leaky injectors or a dead O2 sensor).

High carbon monoxide (CO) emissions are a telltale sign of a rich fuel mixture. On older carbureted vehicles, fuel-saturated plastic floats, incorrect float settings, leaky power valves and misadjusted chokes are often responsible for the rich mixture. On newer vehicles with feedback fuel controls and fuel injection, leaky injectors, excessive fuel pressure and sluggish or contaminated O2 sensors are all possibilities to investigate.

Harder to diagnose are elevated oxides of nitrogen (NOX) emissions. Causes here may include a defective EGR valve, EGR vacuum solenoid or motor, plugged EGR ports in the manifold, over-advanced ignition timing or engine overheating.

(from: http://www.aa1car.com/library/2000/ic60032.htm)

So I think your fuel regulator may be done. Pull the vacuum hose and see if gas comes out or if the engine idle speed changes since the fuel pressure goes up.
I pulled the vac hose with the engine running and get no gas and the engine speed increases slightly.

I apologize, I thought I responded to your post a week ago.
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