Date: Fri, 21 Dec 2007 12:42:30 -0500
Reply-To: Kenneth Wilford <kenwilfy@COMCAST.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Kenneth Wilford <kenwilfy@COMCAST.NET>
Subject: Re: 2.1 High idle/stumbling when engine cold
In-Reply-To: <BAY134-DAV8E6B62FEE084D6E41C61EDB5E0@phx.gbl>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Ed, I recently addressed this issue in my newsletter. I will paste it
below. If anyone on the Vanagon list is interested in subscribing pmail
me and I will put you on the mailing list.
Proper Idle Switch Adjustment
Many folks call me with the complaint that their Vanagon is not idling
properly. Either they are idling too high or too low (stalling) or the
idle isn't steady. There can be several factors that contribute to this
problem however most of the time the culprit is an out of adjustment
idle switch on the throttle body. This switch is located below the
throttle body on 85-92 Vanagons and most folks don't even know that it
exists. However if the computer is looking for a signal from it and is
not seeing it, then it thinks it that the van is still driving down the
road and not sitting at the light. I am going to give instructions for
inspecting and adjusting this switch for 85-92 Vanagons.
Go to the rear of the van with the engine not running. Remove the engine
lid and set it aside. At around the middle of the engine compartment you
will see the throttle body attached to the metal air distributor for the
intake. Use your fingers to move the throttle arm on the top of the
throttle body from where it is at rest (idle position) to the full
throttle position (as far as you can move it). Right when you are
getting to the full throttle position you should hear a small "click"
noise. Now slowly move the throttle arm back to idle position. Right
before you get to this position you should hear the same small click. If
you don't hear it then the switch is out of adjustment. If you hear it
then test the switch for continuity with a multimeter. It should have
zero resistance at idle and full throttle position. If it doesn't then
you need a new one.
If you need to adjust the switch, the easiest way to this this that I
have found is to remove intake boot and the two phillips head screws
that hold the throttle body to the intake. Flip the throttle body upside
down. Now you should see a black plastic cover that goes over the
switch. Pull it off and set it aside. You will see the metal arm of the
switch that rides up against the plastic cam that actuates the switch.
The end of the arm is in the shape of a "U". Use a pair of needle nose
pliers and tweak the end of the arm. You want to bend the part of the
"U" that touches against the cam so that the "U" is just a little bit
wider than it was (not a bunch, just a tweak). Now flip the switch over
and try the test again. Tweak the "U" until the switch works properly at
idle position. Now put everything back together and start the van. It
should idle properly at around 950 rpms.
Some folks try to work around this problem by raising the rpm or
unplugging the idle stabilizer valve on the center of the engine. If you
notice this valve unplugged, plug it back in. If the RPMS are still too
high you might want to check your timing with a timing light. If the
timing is on the money (7 degrees BTDC) then adjust your rpms down by
turning the idle air screw (large slotted screw on the top of the
throttle body) in a little. Count your turns so that you can put the
screw back to where you had it originally if you find your real problem
isn't this screw.
If you are still have a problem with your idle after doing all of this
then either your idle air stabilizer valve or the idle control unit are
faulty. I would try cleaning the valve with carb cleaner and see if this
helps. If not then swapping in a known good idle air valve or ISCU would
be a great way to troubleshoot this problem. If known good ones aren't
available to borrow then you just need to flip a coin and decide which
of these two expensive parts you want to try to replace first. Smell
your ISCU (located behind the tail light on the passenger side. If it
smells burnt then it probably is and needs to be replaced. I know they
are expensive but having a properly functioning idle control circuit is
important to keep your van running well, cut down on fuel usage, and
keep the van from stalling when using the A/C or turning. Email me and
let me know if this write up helps you with this issue.
I put out the newsletter every week or so and we tackle common problems
and issues with the Vanagon.
Hope this helps,
Ken Wilford
John 3:16
www.vanagain.com
Ed Duntz wrote:
> I have had my '87 Vanagon to a trusted mechanic for several tries to fix a problem with a very high idle when cold, along with intermittent rugh running/stumbling when cold.
>
> Both he and I have tried various combinations of other AFMs and idle control modules, and he thought he finally had it fixed with a different idle control module and throttle body. It is somewhat better,but my idle still goes up to 2600 RPM within 30 seconds of startup, and there is quite a roughness, like it may not make it down the road, for the first few minutes. When the engine warms up, the idle and running are fine. The temp II sensor was already replaced. I tried unplugging the oxygen sensor, and don't see any difference.
>
> Any ideas?
> Thanks,
> Ed in CT
>
>
