Date: Fri, 27 Apr 2007 10:32:12 -0700
Reply-To: Keith Hughes <keithahughes@QWEST.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Keith Hughes <keithahughes@QWEST.NET>
Subject: Re: vanagon Digest - 26 Apr 2007 to 27 Apr 2007 - Special issue
(#2007-436)
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>Date: Fri, 27 Apr 2007 09:53:20 -0400
>From: Jake Beaulieu <jbeaulie@ND.EDU>
>Subject: hard start, for 2 years!
>
>Hello,
>
>1982 air cooled Westy, Federal model (no O2 sensor)
>Relatively new Boston Bob motor, compression 141-157
>
>I have a hard starting problem that has been plaguing me for the last 2
>years, I need a fresh idea. When the motor is cold, or is warm but hasn't
>been run for 10 or more minutes, it starts hard and wants to die. I need
>to keep the throttle open to keep it running. After fighting with it for
>about 5 minutes the idle comes up and it starts running smoothly. After
>it is good and warm it runs great, but my gas mileage has dropped from 18-
>20 to 13-15. I installed an O2 sensor and it indicates a rich running
>condition. It reads 0.6V @ 30mph, 0.7V @ 55mph, and 0.8V @ 70mph. The
>exhaust isn't warm enough at idle for the O2 sensor to produce a signal.
>
>
>Another symptom that seems to point to a too rich condition is gas in my
>oil.
>
>
There's really only a couple of ways you can get gas in the oil, and if
you don't have a dead cylinder (i.e. does not fire at all), there's
really only one. You have to be dumping gas into the cylinders when the
engine is not running, and about the only way that can happen is with
seriously leaky injectors. Pull the injectors and check the spray
patterns, and look especially for fuel leaking when they shut off.
There should not be more than a drip or two. My guess is that you'll
find one or more injectors leaking significantly.
>This is the 2nd or 3rd time I have asked the list for help on this. I
>have done every test in the fuel injection and ignition section of the
>Bentley several times. I installed a new AFM and Temp II sensor, even
>though the old one tested out fine. I have a web of extra grounds running
>from the chassis to the motor and alternator. My only new clue is that my
>vaccuum is very low when it is first started (2-5in Hg) and comes up to 13-
>14 in Hg at a warm idle.
>
Well, according to your earlier description, you're not "at idle" when
it's first started (i.e. the throttle is open to keep it running). With
the throttle opened past normal idle position, and the engine RPMs in
idle range, the vacuum will be very low. You're only going to have high
vacuum when you generate a high pressure drop across the throttle plate.
>I would like to see this higher.
>
If the idle adjustment (air bypass) is adjusted to allow more air around
the throttle plate - which is almost certainly the case given how rich
you're running - you can't get any higher.
> I have plugged
>up every outlet on the air plenum and intake boot and this did not have
>any effect on the vacuum. I think I am going to pull the throttle body
>and air plenum next week and run some test to make sure the throttle body
>gasket isn't leaking at the bottom.
>
>
>Lifters are set at 0 lash warm,
>
*Really* bad idea IMO.
> which is equivalent to 0.006 cold as I understand it.
>
Nope. There's no way to infer that. Zero lash *warm* will equate to
valves not fully closing when *hot*. Now, I assume that since you're
talking valve lash, you have solid lifters in you motor. If you have
hydraulics, you're way off base on adjustment. Hydraulics should be set
to zero lash (i.e. just touching the pushrod and valve stem surfaces),
then tightened two turns (or 1 1/2 turns per some folks). Make sure you
run the motor for several minutes to pump up the lifters, then allow to
cool for 4-6 hours prior to adjustment.
> Could my low vacuum be
>related to the lifter? Does low vacuum have anything to do with this?
>
>
A couple of ways; if an intake valve is too tight, it won't completely
close allowing leaking into the plenum during the compression stroke.
If an exhaust valve is too loose, the cylinder will not completely
evacuate during the exhaust stroke, and the cylinder will be abnormally
pressurized when the intake valve opens. In the first case, valve
failure is gauranteed at some not too distant time, while in the second
case, aside from beating the valve stem to death, it'll run like crap.
>thanks a ton, I am totally stumped and just about out of ideas.
>
>
First, check your injectors. If you're really getting gas in the oil,
that's the first problem to tackle and fix. Then adjust the valves
correctly (Cold for solid lifters) and see where you're at. Hope this
helps,
Keith Hughes
'86 Westy Tiico (Marvin)
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