Tony,
Yes, a 12 volt vacuum pump does exist! Cadillac used them on their 1985-1987
C-bodies (devilles, fleetwoods) because the (now infamous) 4100 motor
couldn't pull enough vacuum on its own. The pump was mounted under the left
front fender ahead of the wheelwell. They should be plentiful in junkyards.
I hope this helps you.
Randy
73 Imperial LeBaron 4 dr. HT
>From: Lib596@xxxxxxx
>Reply-To: mailing-list@xxxxxxxxxxxxxxxx
>To: Mailing-list@xxxxxxxxxxxxxxxx
>Subject: IML: Where's my vacuum gone? (Longish)
>Date: Tue, 19 Feb 2002 12:29:11 EST
>
>Here is a technical question I hope someone can help me with.
>
>I am always trying to improve the way my dual fuel system (LPG/Gasoline)
>operates.
>For best performance on both fuels I have made a vacuum operated gate which
>closes to restrict the air flow through the air cleaner when operating on
>LPG but stays open for gasoline. This system works like a charm on my Caddy
>but there is hitch with the Imperial (413 engine). There is not enough
>vacuum generated while I am cranking the engine to operate the vacuum motor
>that closes the restictor.
>
>So far I have tried taking the vacuum off every different source on the
>manifold and carb. I have closed off all other vacuum take offs and just
>connected the restrictor motor. I have checked for inlet manifold leaks, I
>have fitted a non-return valve in the line to the restrictor. In addition,
>I
>can't use the vacuum reservoir because it still won't hold a vacuum
>indefinitly and besides, each time I switch to gasoline or turn off the
>engine, the vacuum solenoid would dump the reservoir vacuum. Whichever way
>I
>try, the vacuum motor still won't operate unless the engine is already
>running
>
>I know I could just use a cable to close the gate, but the idea is to have
>a
>completely automatic system with no extra levers, buttons or switches
>inside
>the car. I could also try to find a 12 volt vacuum pump, if such a thing
>exists, just for starting the car but that seems unnecessarily complex.
>
>Is there a reason why the cranking vacuum is so weak on these engines? Is
>there a way to increase it?
>
>Hope someone has some ideas, I'm right out
>
>All the best,
>
>Tony V.
>
>
Back to the Home of the Forward Look Network