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jeffmiller

emissions failure

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Help!

'72 2002, brand new weber 32/36 with CD's jetting prescription - including float level, new ignition parts, timing set with light, vacuum advance distributor, valves adjusted recently.

I took the car for inspection today, and it failed for emissions. CO% was 8.1, tested at normal idle speed (about 900). HC (PPM) is 384.

When idling for a while, exhaust smokes quite a bit. If I drive aggressively, exhaust runs clean at idle immediately after, but starts smoking again after idling for a while. If I drive non-aggressively, it smokes at idle right away. It does not smoke while actually driving.

Idle speed screw is in more than 1-1/2 turns to idle at 900. at 1-1/2 turns, idles at maybe 300. The screw is supposed to be 1 to 1-1/2 turns in from when it initially touches the plate that it supports, right?

I tried switching out the primary idle 60 jet for a 55 and for a 50. The 55 seemed to maybe reduce the problem, but not eliminate it.

Should I be adjusting the other jets, or is the primary idle the only one that would make a difference for this?

What am I missing????

Thanks.

-Jeff

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The power valve in bottom of the bowl might be leaking causing rich idle or caused by loose main jets. My carb has 55 idle & make sure there is an o-ring on the jet holder. Main jet is 140. Max allowed is 5.50 in my city. The smoke can cause the HC to be higher. Brake fluid from inside the brake booster sucked through the vacuum hose into the intake manifold burns white.

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....and just for the record:

"CO was 8.1% tested at normal idle (about 900) HC 384 ppm"

my '76 passed CT emission tests and when adjusted correctly

gave readings less than half than yourswith "My Jetting"

so back to-

is the oil clean and new?

head gasket leaking?

condition of spark plugs? wires?

timing "BALL" set at what rpm ?

Compression readings?

you may just need to work on your IDLE speed (850+/-)

and IDLE MIXTURE screw adjustment to get to 3.0% CO

and that will result in lower HC (needs to be 150ppm or less)

which is with an excellent running motor at idle. When your HC

is above 200 ppm you have something wrong with your 'settings'

- emission controls fitted or not!.

ANY SMOKING is not good - black, blue, white, yellowish -

you have something that is only going to get worse

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Help!

'72 2002, brand new weber 32/36 with CD's jetting prescription - including float level, new ignition parts, timing set with light, vacuum advance distributor, valves adjusted recently.

Float needle valve/seat? Slow leaker will over fill float bowel/rough idle like having the choke on. If it runs right on throttle it would get my first look.

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Thanks for all the suggestions everyone.

Compression is:

1: 146

2: 141

3: 142

4: 155

Not the best readings, but this would suggest that my head gasket is ok, right? I hope so!

Spark plugs and wires are pretty new, but plugs have endured a lot of carburetor trouble, and are in rough shape. It seemed to do better even after just cleaning off the spark plugs a bit, so I'll get new ones and see if that does it.

I'm also going to double check the float bowl level, because I've been a little unclear as to exactly what positions the measurements are to be taken at. I'm going to take pictures and have you guys verify.

Thanks!

-Jeff

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your compression number are in the acceptable range and are within 10% of each other, the common standard. When you go for emissions testing, you want everything right, clean properly gapped plugs are near the top of the list along with fresh oil and filter, dwell, etc. what CD says is pretty much gospel

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