Intake Air temp sensor (cont'd)

[Brandon Rogers]

Here is what I ended up doing Friday:
 
Went to the local VW dealer w/ a spare IATS in hand - asked for some
connectors that would slide onto the IATS.  He brought back a wire with
two gold connectors - they wanted $7!!!!!!! for a 6 inch wire with a
connector (gold) - and I needed 2!!!!!!  Luckily the parts guy thought
that was silly, too, and charged me "only" $7 for two - my time is worth
more than further deal hunting so I took them.  My intention was to try
the slide-on connectors for the IAT and check resisitance/performance -
if no good go back and solder.
 
Previously Steve Eiche cleaned up my connections, using some a 3"
section of wire, gold crimp connected to the harness and soldered with
tabs to the sensor.  Where the wires came off the soldered tabs is where
they both broke.  So I took my new $3.50 wire w/ gold connector
sections, trimmed to length, used an un-insulated butt connector, cut in
half, to crimp together to the harness.  Using the half butt connector
allowed me to overlap the two wire section completely inside the
connector - I assume this allows better conductivity.  I put long
section of heat shrink over each wire individually, all the way up the
end of th connector that slides onto the IATS.  Then a larger single
heat shrink tubing over the two wires.  I felt the wire coming out of
one the butt connectors was a little flimsy - so I took a short section
of braided vacuum hose and put it around the wires, zip tied, to keep it
from flexing, and thus more weakening.  Factory boot installed.  Reading
at pins 30 adn 44 was right around 495 Ohms - close enough that I don't
recal the difference - might have been 492....
 
The real test was Saturday - I took the urq out, with a friend in his
'83 - and we just burned some petrol up the mountains - about 300 miles
worth.  And the car worked great. No falling face. No CEL.  There was
maybe a time or two where there was a hint of hesitation so I may go
back for some further clean up at some point - but overall the car was
incredible - 3B w/ RS2 turbo power in the urq allowed me to take
advantage of some extra passing opportunities in the twisting moutain
roads.
 
Brandon
'84 urq w/ 3B

-----Original Message-----
From: Ben Swann [mailto:benswann at comcast.net] 
Sent: Saturday, September 08, 2007 9:31 PM
To: 'Brandon Rogers'
Cc: quattro at audifans.com; 200q20v at audifans.com
Subject: Intake Air temp sensor (cont'd)



My understanding is the resistance on these is so sensitive it is best
to soloder them.  I did one using 20guage crimp connectors from Radio
shack - worked ok as these are tiny precise connectors that fit the wire
tightly prior to crimping.  I tried doing a solder job, and not the
easiest so you will likely end up crimping and with the small crimp
connectors should be fine - just do a pull test and no wire
wiggle(technical term) in the crimp.

 

I'm sure the added resistance of the hanging wire strands could have
thrown the sensor reading off, and in this case even a marginal crimp
will be superior to what you had.

 

Ben

 

[Date: Fri, 7 Sep 2007 08:49:07 -0600

From: "Brandon Rogers" <brogers at terrix.com>

Subject: Intake Air temp sensor (cont'd)

To: "200 20V List" <200q20V at audifans.com>

Message-ID: <003201c7f15e$3eb3a950$0f01a8c0 at BCROGERS>

Content-Type: text/plain;     charset="us-ascii"

 

so after checking resistance across pins 30 and 44, and finding things
within spec (495 Ohms) - I stopped thinking about the problem - plus the
CEL light didn't come back on.  (My urq is wired so the OXS light
functions as the CEL).  But then driving yesterday a couple times the
power was very flat - like the ECU was pulling timing waaayyy back or
keeping the WGFV open as much as possible.  And on the way home last
night it was not pulling strongly like normal - a couple times.  So I
went back to the IAT wires -pulled the boot off - my wires are soldered

- and I think they were hanging on by a few strands as they broke off
when I was fiddling.  So hopefully that was my problem.

 

So my question is what is the list consensus on soldering vs connectors
for the IAT sensor? 

 

thx

 

Brandon

'84 urq w/ 3B

 <http://www.terrix.com/>]