Effects of Temp Sensor I and plasti-coated duct update

["Eric Hambleton" <ejham@domain.elided>]

Contained within the AFM of a Bosch L-Jetronic system is the
"Temperature Sensor I" (as opposed to the Temp Sensor II above the
water pump) whose purpose is to monitor air temperature at the AFM
intake. From what I've been able to find, there's virtually no
documentation on testing, troubleshooting, or the overall action of
this device. The only thing I've read was from the Robert Bosch Co.'s
technical guide to the system which stated it's purpose but nothing
specific regarding the extent to which the sensor modifies fuel
delivery.

With the recent conversation regarding under-hood temps coupled with a
long-standing curiosity on my part, I was wondering if anyone here
knows more.

- ---

Some of you may recall my post regarding my plan to try coating an
aged intake duct with spray-on Plasti-Dip. I wanted to report on how
this has worked out so far.

To recap: After getting a nasty bit of sticker-shock when reading the
price for the rubber intake duct that runs from the AFM to the
throttle, I mused on the possibility of coating a leaky one with the
type of coating used on tool handles. I happened to have a can of this
stuff on my garage shelf unused for some time -- I can't even remember
when or why I bought it.

So, I pulled the duct from my parts-car and set out. After cleaning it
thoroughly with Gunk and then hot water and dish detergent, it passed
the 'white glove test' of being free of oil and grease. I then sprayed
on the plastic in multiple coats. The process did not go completely as
I'd envisioned: each application of the spray-on stuff produces a very
heavy coat (not like spray paint) and contains allot of Xylene or
other evaporative agent which boils free from the thick coating
resulting in small holes when dry. Patience is required to get things
right.

After installation, I had to adjust the idle air settings upward which
I take as a sign of successful leak elimination. Furthermore, the car
has been in more-or-less continuous operation here in the hot Southern
summer weather -- even caught in two hour-long traffic jams in 95
degrees -- and the coating job shows no signs of pealing or other
failure.

I'd have to call it a success thus far. I would recommend the use of
the brush-on rather than the spray-on version of Plasti-Dip. It is
available at Home Depot (a chain of large home improvement stores
here) in several colors. I happened to have red on hand but black is
also available. The red looks interesting, though.

All-in-all, I think the process is worth the hour or two of labor and
<$10 cost when compared to the >$100 cost of the new part.

If anyone decides to try this out, please let me know how it goes for
you.

- - Eric Hambleton, Marietta, GA
1983 GTV6 -- Felicite

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End of alfa-digest V7 #874
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