Date:         Tue, 21 Aug 2007 15:02:38 -0700
Reply-To:     Evan Mac Donald <macdonald1987@SBCGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Evan Mac Donald <macdonald1987@SBCGLOBAL.NET>
Subject:      Re: Rough running till warmed up
In-Reply-To:  <AB2D056B-CF45-4267-8BE0-75112D9821EA@gmail.com>
Content-Type: text/plain; charset=iso-8859-1

There is a possibility that should be looked at. The butterfly plate in the throttle could be worn, and the shaft and plate do not settle into place properly. This will have two major effects. One, the throttle plate will not seal off the throat of the throttle body properly, so you in effect have a HUGE vaccuum leak. Second, and worse for us Vanagon folks, the shaft will not always rotate into place, to actuate the idle cut-off switch. No matter how well adjusted you think you have it, if the throttle shaft is wobbling or sticking, it will change the apparent adjustment every time the throttle is actuated.

  Your idle improves when you tap the gas most likely because as the engine is running, it "bounces" the throttle plate and shaft mostly back into place, so it all works (mostly) as it should.

  I could not get a reliable idle on my '85. I tried adjusting everything. The idle, the timing, the idle cut-off switch, if it could be moved, I did it. Nothing worked. Finally, I removed the throttle body, and examined the plate and shaft. The bottom 1/16" of the plate was worn away. This left a large gap at the bottom, and also would allow the shaft to drop, and slightly wedge itself open. When I carefully rotated and lifted the throttle shaft to "closed", the switch would click, but a big crescent-shaped gap would appear. If I just let the throttle return spring pull it closed, it was hit and miss. Sometimes full closed, sometimes not.

  A replacement throttle body cured all of this.

  Just as an experiment, try pushing the throttle open, then letting it go closed again, before you turn the key to start. If you have a decent idle right away, you have a bit more information for troubleshooting...

Craig Cowan <phishman068@GMAIL.COM> wrote:
  I set the idle as per Bently. I disconected the Idle control unit and
plugged the two together. Then, i turned the screw till the idle was
properly set and replugged everything else together (with the
ignition off of course). Nothing. This made no difference. I was
further investigating and seem to have found that it has nothing to
do with being "warm". If i start the car, it runs and dies. It will
continue to do this untill i give it sustained throttle for 30
seconds or a minute, then it will settle down and idle properly. Now
say i've run it for a while (10 miles at 55mph) then shut it down. I
go into the pizza place to pick up a pizza, lets say it takes like 5
minutes. The engines still warm, when i turn it back on the engine
will register as warm.....but the idle will still be pathetic untill
i give it a little gas, then it will settle back down. I'm fresh out
of ideas. The timing was just set (by ear by a mechanic) which ended
up making a huge difference in the performance of the car, but might
have somehow effected this? There was a vaccuum line loose off the
top of the distributor when i first found this problem
yeseterday....i put it back on.....the problem still exists. Any
ideas would be welcome.

Thanks again!
-craig
'85GL