Re: [T3] Too much advance

[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.

> 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. I don't know the
> accuracy of my vac gauge and will try to get a better one to re-do the test,
> but this seems way out- actually the opposite of what I originally thought.
> Maybe the diaphragm has stiffened up with age and is
> causing that slower response. 

Yes, this seems odd.

> The part number for the vac can given on the first page of that
> bulletin is 311 905 271 F. All I could find on mine was the number 507
> stamped on the arm so maybe its not the right can. 

As Dave suggested, 507 is the last 3 digits of the Bosch part number. 
Unfortunately, there's no correlation between the Bosch number and the VW 
number. If you go to a repair shop that uses Bosch parts, they should have a 
Bosch catalog which should show your car, with the Bosch part # for the dist 
and the Bosch # for the vac can. I can't do it for you because my Bosch lit 
only lists US parts.

Those 3 digits are the only identification you will find on the can.

-- 
*******************************
Jim Adney, jadney@vwtype3.org
Madison, Wisconsin, USA
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