[T3] Mystery Miss

[Jim Adney]

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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