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High Carbon Monoxide Emissions (86 pulsar nx)

Here is the story. I got a 1986 Nissan Pulsar NX from a friend. The emissions results back before it was taken off the road was:

Driving Hydrocarbons (HC): 71ppm (MAX: 314ppm) Driving Carbon Monoxide (CO): 0.26% (MAX: 2.41%) Driving Oxides of Nitrogen (NOx): 2655ppm (MAX: 3390ppm)

Idle Hydrocarbons (HC): 84ppm (MAX: 402 ppm) Idle Carbon Monoxide (CO): 0.10% (MAX: 4.54%)

Then the car was taken off the road because of a shot carburetor (would stall out and you'd have to pump the gas to keep it going), which i rebuilt, and the car drives fine, except i can't really get it to idle below 1000RPM (suppost to be at 650RPM). So i turned the idle speed screw up to about 1000 RPM so i wouldn't have to drive with two feet. Sometimes it stalls going around left corners, is this a sign of a low float level?

Anyway here is the current results:

Driving Hydrocarbons (HC): 247ppm (MAX: 314ppm) Driving Carbon Monoxide (CO): 8.56% (MAX: 2.41%) Driving Oxides of Nitrogen (NOx): 127ppm (MAX: 3390ppm)

Idle Hydrocarbons (HC): 73ppm (MAX: 402 ppm) Idle Carbon Monoxide (CO): 0.16% (MAX: 4.54%)

So driving hydrocarbons are up, but still below the max, driving carbon monoxide is through the roof, and driving oxides of nitrogen are barely there.

New spark plugs, dist cap, rotor, spark plug wires, pcv valve. basically i want the thing to idle and pass emissions. so what are my problems?

Reply to
jsanders
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The problem lies with your rebuild of the carb. My guess is the float level is WAY too high. It's too rich which makes the CO high and the nox low. If this is a feedback carb the O2 sensor and the stuff it operates may not be working either. Time to open that carb back up!

Reply to
Steve T

no o2 sensor, this is a canadian model. and i don't think the float level is too high (the window on the side of the glass shows) its way too low. thats why it stalls out going around corners sometimes. would a too low float level cause the emissions to go through the roof? cause the window shows that the level is way below the middle level where it should be.

Reply to
James Sanders

It wouldn't make the CO high, it would make it low.

I have no idea what you did wrong but given it runs poorly and also is reading too rich, something wasn't done right. Maybe you have some jets mixed up?

Reply to
Steve T

the jets were matched up with the ones in the repair diagram. turns out the kit was wrong so the wrong gaskets and needle valves and accelerator pump is in there. i've got the right kit now and will rebuild the carb this week.

Reply to
James Sanders

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