Date: Sat, 23 Oct 2010 15:37:50 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: 91 Carat - Rpm hunting
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'finally convinced' ....!!!!
I have said this on this list about a thousand times..
the throttle switches are USUALLY not making contact at idle.
I have fixed dozens, and dozens of vanagons .with that adjustment. .
it's where I start in any running/idle issue diagnosing.
the method to do it on a 2.1 is a bit weird.
If things are not rusted or corroded , and you have the right allen wrench,
and the allen hole is not striped out ..
you can do the adjustment.
Otherwise ....just had to do this the other day ...remove the throttle body
...
it's very, very easy ......then work on it on the bench.
some of them will not 'reach' anymore to make contact at idle.
no..! - not any feeler gauge adjustment !!
it's an electrical adjustment.
There is a throttle plate stop screw on 2.1 throttle bodies ..
normally you never touch that. I never have found a reason to.
If I found a throttle plate jamming at zero throttle in the bore of the
throttle body ..
I might tweak on that screw a tiny bit ..
but normally ..."nicht germessen."
what you want is it makes contact as close to zero throttle as you can get
it ..
AND .....that it ALWAYS makes contact each time throttle is returned to
zero.
Make sure there is slack in the throttle cable at zero throttle. ( that's
for manual trans ...in any case, make sure throttle linkage is not holding
throttle open AT ALL at zero throttle, auto trans or manual. ) .
once you have it adjusted ..
open throttle and release ( engine off )...........do that about 6 times...
making sure it makes contact at idle each time - using an ohmmeter.
or by hearing it click.
there is a tendency for it to not return totally completely to zero throttle
every time.
if the 'gap' ...
if it makes contact say , at too far from zero throttle...say at 5 %
throttle ..that will get you bucking at low throttle openings.
there is also an electro-pneumatic device you can get that transcends this
whole funky mechanical throttle switch system - that's got to be 20 times
better.
I would also encourage people do 'dig in' ..
to take things apart , etc.
All I ever did, starting with my tricycle before I went to kindergarten ..
is 'take things apart' ...
you'd be surprised what that will reveal..
corrosion, broken things, missing things, loose things etc. etc. etc. etc.
..
wrong work previously done .....super common actually.
no amount of talking or emailing can substitute for 'hands on' ..
and actually inspecting and taking things apart. Then you take what you
learn hands on and get list wisdom to help.
also ....I recommend resisting the notion that 'it's a component' ..
sometimes it IS a component ..a dead/tired starter say ..
but so often ..
like as often as 60 % of the time ..
it's just lubricating, adjusting, fine tuning, tweaking ...cleaning etc.
also ....resist the notion that 'it's one thing' ..
I almost never is...or rarely.
I might find .sure, on dead component..
but I'll find 5 things that are weak or corroded ...and 4 things half out of
adjustment too.
That's by far the more common scenario.
and one place you intentionally always look for weakness or break down is
anywhere electrons and something mechanical interface.
That's almost always where things are weak...
the sweeper contact in the AFM for example...it's got to wear and not work
eventually.
on other hand ...where it's purely electronic ..
not much usually goes wrong there, like inside the ECU.
this throttle switch ...
it 'can't work' that well............ eventually. ( as an example of
weakness where electronics and something mechanical interface )
throttle shaft wears, throttle plate might wear too ...
the switches get stuck or corroded ....or can't reach adjustment ..
the electro-pneumatic switch ..OTOH,
since it senses vacuum to know when the t-body is at zero throttle..
and I imagine has a solid state switch in it, rather than mechanical
contacts..
completely transcends the funky 20+ year old throttle switch.
but always ..
any idling or running issues ...
go immediately, do not pass Go, to the throttle switch adjustment and making
sure it gets contact at idle.
I can tell from here, right now ...there are thousands literally, of
vanagons running right now with that switch not making contact at zero
throttle.
And ...there's tons of shops that will put in all manner of expensive
Components...
trying to fix things and not even do that most basic and simple of
adjustments !
I can't even think of a Vanagon I've seen for the first
time.............that had that switch working right , or almost can't think
of one.
for a fast basic test, engine off, open throttle with your fingers
...should hear the click when you move the throttle off zero and release it
back. If ya don't hear that click, it ain't working ..
and it's pointless to work on idle quality ......
or emissions probably......until that is working right.
and don't be afraid to take things apart..just be super careful.
there is a learning curve ..and sure ..
sometimes you break things the first time you mess with them if it's totally
foreign to you ..
that does happen ..just 'learn' on the less expensive stuff first ! lol.
Don't think 'I don't know' ..
think 'I'll figure it out as I go.'
just be careful.
particularly about dropping bits in bad places...like down the intake. You
sure never want anything like that happening !
what fun !
Scott
turbovans
----- Original Message -----
From: "John Rodgers" <inua@CHARTER.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, October 23, 2010 2:35 PM
Subject: 91 Carat - Rpm hunting
> Volks, you finally convinced me - Scott, David, Ken, others - to check
> the throttle switch per Bentley. Bentley confirmed what youwere trying
> to tell me. So the the FI service manual. Basically - to paraphrase "If
> the settings are not correct, the engine will surge when moved just off
> idle." That is exactly what it does. Idles great. But move that pedal a
> hair, and then it hunts of surges.
>
> Question: As I see it, this is principally about adjusting gap with a
> feeler gage, right? In reading. I see that resistances at open and
> closed positions can be read on a meter. Any cautions there?
>
> Thanks,
>
> John
>
> --
> John Rodgers
> Clayartist and Moldmaker
> 88'GL VW Bus Driver
> Chelsea, AL
> Http://www.moldhaus.com
