Re: Fuel Purge Canister Question (archive)

I don't think that you should connect vacuum directly to the canister. The canister venting into the engine should be controlled via some type of 3 port air valve that is triggered by a vacuum source to the air valve's trigger port. This separates the purge function from engine vacuum. If you need a diagram for the purge system I can pull it off the parts CD.

demet

I have an '83 745i with the "add on" fuel tank purge canister. My question is if this canister should be a complete vacuum when connected properly.

With three outlets on the canister, 1; to carb - plugged 2; to intake vacuum 3; to fuel tank. When I remove fuel tank line and put finger over connection - there is no vacuum. When I plug incoming vacuum line - my vacuum goes up from 10in at idle to about 15 in at idle.

IS THIS CANISTER SUPPOSED TO HAVE A CONTROLLED VACUUM LEAK?? IS IT SUPPOSED TO PULL IN AIR ALONG WITH FUEL TANK FUMES??

If not, can I assume this canister is bad and there should be a complete vacuum in this system? If so, can I simply plug vacuum line to canister without running into any type of recirculating system and not run into any complications?

I am trying to make sure I have no vacuum leaks before I try to increase fuel and boost to engine. Right now, when I plug this vacuum line, vacuum goes up, idle goes down. If this is a true leak, I can then adjust idle to correct RPM,

Thanx for the help in advance,

Mark

Follow Ups:

Re: Fuel Purge Canister Question - Thanx Demet mark 22:35 9/27/2000 (1)
- Some comments demet 09:57 9/28/2000 (0)

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