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Lambda sensor says running rich, but


Guest Anonymous
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Guest Anonymous

At idle, I tuned the mixture screw on the bottom of the carb

back until the lambda sensor gives about 0,20 volt. That is

supposed to be lean. But under mild accelleration and

constant speed, the sensor indicates 0,95 volt, meaning it

runs way too rich. I've just fixed and checked the ignition,

what could cause this?

Thanks,

Hugo

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Guest Anonymous

What you are experiencing are the different circuits of a carburetor. When you dialed in the idle mixture, you did just that, the IDLE mixture. The off idle, cruise and acceleration circuits are tuned by other parts of the carb, mainly jetting, venturies, pump stroke, etc. In order to change the acceleration, you need to change the pump stroke/volume at the minimum. See what the cruise is and go from there. You will probably also have to play with main and air jets to get all the circuits to match (if that is what you want).

Good Luck,

Mike (#87)

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Guest Anonymous

DSCN0022.JPG

URL: http://www.zeebuck.com/02bc/index.htm

if you are rich or lean of stoichometric point. You can't really infer that you are "way rich" at .9V or "way lean" at .2 You will only really know you are in a narow range around stoich point when the sensor reads about .5V. Of course, if you have a wide band sensor, then you would have a meaningful reading off off stoich.

regards,

Zenon

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Guest Anonymous

Modern electronic fuel injection can control the mixture precisely enough to keep it very close to the stoichiometric ration; this is required when using a catalytic converter. A carburetor, i.e. a poorly controlled leak, is not capable of such control. Set the idle mixture in the normal way, confirm that the mixture is rich at full throttle, and don't worry much about other conditions.

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Guest Anonymous

if I ever see it at less than almost full rich, I start to get nervous.

We want to run at 13:1 or so... and that is way above the stoich point. So if I get a stumble, I pull out the meter and hook it up, just to be sure I don't have a lean- out.

Probably saved the engine, as it turns out the mech. fuel pump stops properly feeding my 38/38 at about 6K. Not a good place to lean out at WOT.

t

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