The gray indicates engine oil. Valve stem seals.

Dennis,
From my phone.
________________________________
From: Don Hanson<mailto:dhanson928@GMAIL.COM>
Sent: ‎10/‎19/‎2013 12:29 PM
To: vanagon@GERRY.VANAGON.COM<mailto:vanagon@GERRY.VANAGON.COM>
Subject: Re: Intermittent smoke after stop signal wait...

  Added....When I said "stinky" that was misleading.   I have never
actually smelled that cloud, since It is behind the van and I am
driving....I just used "stinky" because that is what it looks like it
should be, when viewed in my mirrors....  If I could smell it myself, maybe
I would know if it is gas or oil-smelling....I know it is not coolant,
since I have not added any coolant in almost a full year and I normally log
at least 20k miles or so each year...

On Sat, Oct 19, 2013 at 9:21 AM, Don Hanson <dhanson928@gmail.com> wrote:

>   I sometimes see a nasty grey cloud of smoke from the exhaust of my 84.
> Digifant EMS on an inline VW motor.   I am guessing it may be a faulty
> throttle switch that sometimes goes to 'full rich' for whatever reason.  By
> intermittent I mean....When I go to town, perhaps 1 trip of four, this
> smoke shows up.   It doesn't smoke at every signal....It may do so for two
> in a row, then no smoke at all the rest of the driving around.   It
> sometimes even smokes breifly on start up, but very seldom...
>
>   Here are the specifics of how this occurs and when:  It normally happens
> in the city when I am stop and go driving or hitting traffic lights.
> Everything might be normal without any problem then I will roll up to a
> signal and idle there while the light cycles then as I leave, the van puffs
> out an embarrassing cloud of grayish exhaust smoke, lasting perhaps two
> seconds before the exhaust clears back up and is again invisible.    I have
> also noticed that on start up, then coasting down a longer hill the exhaust
> will backfire....I do have an air leak in my exhaust system which probably
> allows air in to make the loud bang more likely...
>
>    I see no smoke on long hill descents.   Nothing when I redline the
> motor to 6000rpm.   I don't burn much oil for a VW inline, but I do have a
> slight leak at my homemade filler when I park with the nose up on a steep
> incline...a quarter sized puddle below maybe.
>
>    I think my throttle switch is NLA...I think it is the longish leaf
> springy looking type...It seems to click correctly with linkage movement
> and it clicks off when the throttle is closed...when I do it in the engine
> by hand...consistently and correctly..
>
>   Anybody have any other ideas about this stinky cloud of smoke I sometime
> see?   I hate puffing that into our air, though it's probably nothing
> compared to, say,  a coal fired power plant...a minor 2-second visible
> exhaust puff a few times a week...
>