Message text written by INTERNET:Harrymague@aol.com
>Next I tried disconnecting the pipe from the carb to the canister, label
the
canister purge pipe. This stops the problem. This pipe connects the valve
cover and the top of canister to ports on the carbs. Does anybody know how
much of a vaccum should be on this??? I think the pipe vaccum is pulling
too
much from the vent valve connecting pipes, but I can't even guess why. The
carb float chamber are vented to the engine during open throttle
conditions
and to the carbon canister at closed throttle. This is exactly what is
happening. In the closed throttle, that is when the engines dies. In the
open throttle/choke position, the engine runs smoothly.
<
The level of vacuum at this port is the depression at the venturi. This is
the vacuum that draws fuel through the metering jet into the air stream.
If this same amount of vacuum is applied to the float chamber then there
will be no pressure differential to draw fuel through the metering jet.
This is appearently what is happening. Now the question is why is this
vacuum making it all the way to the float chamber?
The big hose (from the venturi port and valve cover) has vacuum. It is
connected to the charcoal canister via the center port. On cars with the
anti-run-on valve system there should be a restrictor in this port to
provide a pressure drop (or in this case a vacuum drop) between the
canister and the vacuum source. The two other lines at the top of the
canister will sense the vacuum at the top of the chamber, above the
charcoal but after the restrictor. Proper operation is dependent on the
air pressure at the top of the canister to be very near atmosphere. As the
venturi draws air through the canister (through the charcoal there will be
a pressure drop (there always is. can't fight the laws of nature) but the
restrictor will limit air flow and the pressure drop through the charcoal
will be insignificant.
If the restrictor isn't there there will be a torrent of air passing
through the charcoal and there will be a significant pressure drop across
the charcoal which will present itself at the float chambers.
If the charcoal is packed or clogged it will not allow even the restricted
amount of air to pass without a significant air pressure drop which will be
present at the top of the chamber, and thus, the float chamber.
If the bottom port of the canister, or the hose to the ARS valve, or the
valve port itself is clogged (will not allow free passage of air) then
there will be no flow across the restrictor and vacuum will be applied to
the float chambers.
These are a few things to check out. If I recall, you said you put in
another canister. If so, was the restrictor in the center, top port? Can
you blow air freely through the ARS valve and the interconnecting hose?
will air pass freely through this new canister?
Check these things out and write back.
Good luck
Dave
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