Date: Wed, 26 Apr 2006 20:27:53 -0400
Reply-To: Dennis Haynes <dhaynes@OPTONLINE.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <dhaynes@OPTONLINE.NET>
Subject: Re: idle and black tower
In-Reply-To: <vanagon%2006042600362138@GERRY.VANAGON.COM>
Content-type: text/plain; charset=us-ascii
If you are getting enough air through the engine crankcase to effect the
idle, you have a problem. Blow by should have little effect as it should
be burned gases with very little O2 left. Have you checked the valve
cover gaskets to make sure they are not cracked or that the tops have
fallen down? Air can get in and oil does not always leak out.
The breather tower does not have any moving parts. It is just a baffle.
If it is clogged with goo and carbon, you have a neglected and/or tired
engine.
In the world of emission controls, the closed crank breather and in some
cases PCV valves were the first starting in 1968. As an emission control
device, disabling it is not a good thing.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
Of Daniel L. Katz
Sent: Wednesday, April 26, 2006 12:31 AM
To: vanagon@GERRY.VANAGON.COM
Subject: idle and black tower
list:
interested in discussion of following $0 successful fix of very poor
idle
on '84 1.9l.
essentially, pulling the 3/4" hose off black tower outlet, venting
blow-
by to the atmosphere, and plugging completely the free end of the hose,
completely solved the problem. she idles smoothly and beautifully at 900
rpm. to finish, i'll have to use a long 3/4" hose to conduct fumes out
of
engine compartment, and plug the intake port directly.
i really put this off for a long time because she ran so well otherwise.
in the interim i experimented with conventional pc valves intalled
inside
the 3/4" hose oriented so as to stop a front fire from entering the
crankcase, and modified not to close at high blow-by pressures - but
always ran into at least a noticeable amount of trouble building up
crankcase pressure, with symptoms such as oil eventually rising and
leaking out of the dip stick tube.
a valve routing the blowby down the usual route to the intake
off-idle, or a vent to the atmosphere at idle, would be the optimum
system.
the van has a bit over over 200 k miles, and the black tower is
certainly
original. possible the tower is malfuncting, perhaps running wide open
all
of the time, but my experience with restricting the flow downstream
suggests that a possibly more restrictive (at idle) replacement would
lead
to the same sort of crankcase overpressure - just too much blow-by.
also,
she idles best with the intake port completely sealed. i have not
measured
the compression, but the engine is "loose", as it doesn't stop turning
immediately on shut-down, and the engine will not hold parked on even a
very modest incline.
all standard electrical tests related to the afm check out, i've done
the
capacitor modification, coolant temp sensor ii is fine, grounds are fine
(maybe 10 mv between block and frame/body/ecu case), o2 sensor is fine,
and i run initial timing 12 deg btc (i.e., with idle stabilizer
bypassed).
today's fix was the result of a propitious break down su afternoon, 50
feet from home, under a story book sky at 70 F, where she would start
and
then immediately konk out, and stepping on the gas would not keep her
lit -
in fact, it felt as though the throttle cable was broken or
disconnected,
which was the first thing i checked.
thanks,
dan
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