Re: 78 Spider: Where do these vacuum hoses go!

["Paul Irvine" <pi@domain.elided>]

Date: Tue, 9 Apr 2002 11:41:33 -0600
From: "Jeffery Francom" <jfrancom@domain.elided>
Subject: 78 Spider: Where do these vacuum hoses go!

This is your idle air circuit. The little idle air manifold that is mounted
midpoint on top of the intake has 5 small fittings and one large one. The
large one goes directly to the corresponding one on top of the air cleaner.
It is your idle air adjustment and should have a washer and an o-ring behind
the threaded fitting. The four smaller ones go to the individual fittings at
each throttle and the fifth small one goes to the small fitting on the
air/oil separator which is the canister mounted forward of the air cleaner.
There are two small fittings on it, the lowest one is the oil drain and goes
to a fitting on the dipstick tube. The higher one is the one that connects
to the intake. The large opening on top of the air/oil separator goes
directly to the corresponding fitting on the cam cover and the one on the
bottom goes to the corresponding one on the bottom of the air cleaner. The
two small fittings on the bottom of the air cleaner are fluid drains. You
can attach hoses to them to drain whatever comes out free of the engine
compartment but it's not absolutely necessary.

When everything is hooked up, and all the hoses are good, with the engine at
operating temp all of the throttles should be completely closed and all of
the idle air is supplied through the idle air manifold and the small hoses
to the throttles. The small hose to the air/oil separator is to keep
negative pressure on the crankcase vent while idling. You should be able to
pinch each one of the throttle supply hoses one at a time and get that
cylinder to completely drop off. If not you've either got a leaking hose
(one cylinder fails to drop off) or your throttles are out of sync (two fwd
or two aft cylinders fail to drop off)  or the SPICA is not set up properly
(no cylinders drop off). Once the SPICA and throttles are set right then you
can set your idle speed with the threaded nipple on the idle air manifold
that the large hose from the air cleaner goes to.

Paul Irvine - Antioch CA
Project Alfa - http://home.pcmagic.net/pi

Jeffery Francom wrote:
-------------------------------
I am hoping someone can help with something.  I have a 78 Spider that I am
trying to get back on the road.  Several of the small hoses (vacuum hoses)
are rotted out and a few even missing.  So I am trying to replace them, but
I am running into a problem.  The problem is that I am not sure where some
of the hoses connect.

I have an owners manual for a different year spider and most of the hoses
show up on that (one per injector etc.)  But the ones I cannot figure out
are the two small hoses on the bottom of the air filter housing, one that
comes off of a small canister thing that is near the air intake on the air
filter housing... Then there is another four-way hose connection that I
cannot figure out at all.

Does anyone have a diagram that shows where each of these hoses connect?  As
several are still not in place, I am sure I must have a vacuum leak which
may account for the very high idle!  Any thoughts would be appreciated!

Many Thanks,
Jeffery Francom
78 Spider

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