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Re: [T3] Too much advance


----- Original Message ----- 
From: "Jim Adney" <jadney@vwtype3.org>


> On 7 May 2004 at 20:39, Mark Seaton wrote:
>
> > Also I get 32 deg mech adv at 3500 whilst the specs say I should have 26
at
> > 3500 (a difference of 6 deg). So maybe I should just retime at say 2 deg
> > advance at idle to take care of that offset? (instead of 7.5)
>
> I'd recheck your measurements first, but once you're convinced that
they're
> right, moving the idle timing is worth a try.

Doh!- none of us noticed that the vw charts are adjusted so they start at 0
deg advance- my figures were actual advance figures (starting at 7.5 deg) So
it looks like theres not much wrong with the mech advance at all.

> > As for the vac advance there are more significant differences. The VW
graph
> > shows that at 10cmHg I should be about half way through the advance at
6deg-
> > on my graph I'm only just starting at about 3 or 4 deg. Mine maxes out
in
> > the 20-25 cmHg range where it should do at about 12cm Hg.
>
> Yes, this seems odd.
>

I re-checked my vaccuum and I think I must have had a leak when I took those
readings. Yesterday I hooked up the gauge to the can via a tee and just
sucked on the line while looking at the advance with the strobe and I can
say that the vac adv stops at about 16cmHg which is not so far from spec.

So my dizzy looks OK, but the engine still runs better without the vac. I
guess it must be something else- like the vacuum source/characteristics
being wrong.
Sorry this seems to have been a bit of a red herring.

Mark


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