Re: [T3] 72 FI missing/sputtering

[fess <fess-vwtype3.org@fess.org>]

<x-flowed>
On Nov 16, 2005, at 6:46 AM, Jim Adney wrote:

> On 15 Nov 2005 at 17:32, fess wrote:
>
> > I think I had been ignoring a slight missing or sputtering problem on 
> > the
> > short drives I've been doing. But now that I drive it on the freeway 
> > for the
> > first time in a while, I'm feeling like it's not in very good shape.
>
> > It seems to be slightly intermittent, but perhaps relative to the
> > throttle position.
>
> What year? If it's a 72-3, suspect the throttle valve switch.

It's a 72.  [ door sticker of 11/71 ]

>  You can test this
> by disconnecting the switch for a few days and seeing if the miss goes 
> away
> while driving.

Hmm. Ok, I can try that. I have to figure out which switch that is.

> Otherwise, check the SP connectors for their 1000 Ohms, and the spark 
> plugs
> themselves for wear (rounded electrodes.)

Ok, I can try this too. thanks.

Last night I drove it home and tried to pay more attention.
It seems to happen in correlation with RPM or possibly load.
I think that it happened at slightly lower RPMs  when
I was going up an incline.  So, less about
throttle position.

I'm not sure I may know what missing / sputtering is,
so here's my laymans description of the event.

As I accelerate I hit a point where suddenly it
seems to loose power. The noise the engine makes
seems to be a little bubbly like someone
just blew put the pipes through some water.
but it's not that loud.

After driving home, I started to suspect advance mechanism?
since that seems related to RPM.

So, I pulled the distributer cap, and twisted
the rotar,  it turns a little, then snaps back.
I pulled the small vacuum hose off the intake
that goes to the outside of the can on the distributer.
I sucked on that and watched the arm tighten.
I sucked pretty hard, and it moved the plate
in the distributer.  Is that supposed to move easily?
could that be the issue?

I also found that the large vacuum hose from the
air cleaner to what I think is the deceleration switch
was disconnected. I connected that, but it didn't
have any effect on the problem.

Last I checked the throttle position switch
for the clicks. It makes 20 clicks
but clicks #3, #5, and #8 are very weird
they sound like a quick series of clicks
rather than one click.  [ like a drummer doing a flam. ]
[ Also at this point, the return spring popped
off, and I don't know if I got it on right.
anyone got a picture? I think the hook might have
partially broken. ]

Anyhow, checking SP wires, and plugs I can do
so I'll check all that stuff next.

My fear is that the timing is just off, which
I don't feel confident doing myself.
However I did have it's valves adjusted
and timing done a few months ago.
[ looks like he lubbed the points cam too. ]

--fess


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

</x-flowed>