[T3] Mystery Miss
Jim Adney
jadney at VWType3.org
Wed May 11 07:29:06 PDT 2016
On 10 May 2016 at 21:51, Daniel Nohejl wrote:
> Well, in the spirit of intermittents, my intermittent has vanished for the time being: I haven´t had a miss since last Friday morning and almost 60 miles of driving. If it matters, all of last week was damp, rainy, and miserable. A bit as if the climate of Portland or Seattle had settled over NYC. Now, it´s warmer and completely dry. Maybe I should spray around the engine with a spray bottle and see if I can replicate my mss. Perhaps it is/was weather and wetness related.
This may be an important clue. VW added some special red silicone
rubber boots/seals to the SP connectors, starting around '71. These
keep the upper part of the SP ceramic insulator dry, even if the
cooling system is blowing mist over the heads. If you don't have
these red boots, get some. The VW part # is 311 905 444A. I just
called my dealer and they said this is still a good number, but the
price is now out of sight: $22.91 each!
Every aircooled VW should have 4 of these, because they are immensely
useful. They prevent one type of damp weather problem. This problem
will only happen on a cold engine; once the SPs are hot, water gets
boiled off the insulator instantly, but on a cold engine, moisture on
the ceramic SP insulator will short your spark to ground.
Since you've just put this engine together, it's unlikely that the
drain hole in the bottom of the fan housing is plugged up again so
soon, but that's also worth checking.
Now that I see how expensive these are, and I don't find alternate
sources anywhere, I'm not inclined to sell any of my remaining few. I
do, however, have a few of the earlier versions, which I don't care
for, because they tend to stay on the SPs instead of the connector
and keep you from getting your SP wrench on there. I havn't tried
this, but I'm thinking that they could be glued onto the brown SP
connector, so they would stay in place. If that worked, they should
work just as well as the later version. If you want 4 of those, you
can have them for $10, including shipping.
I just took a photo of the different versions. I'll post that to your
samba thread.
> In other news, my gas mileage when commuting to and from work (local, highway, traffic) is only 17.4 mpg over many tanks. That´s fairly pathetic, no?
Yes, 17 is pretty bad, but if your commute is short or includes lots
of stop and go traffic, maybe it's reasonable. My mileage always
improves with the weather. Engine misses will also bring your mileage
down, since each miss is one more cylinder's worth of gas thrown
away.
OTOH, your pressure sensor may need to be leaned out a bit more, or
try one of the ones that hasn't been tampered with.
--
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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