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Fun with Sensors...Follow Up...

Well, but a new 4 pin temp sensor and knock sensor on my 90 the other day,
and I figured I'd post a summary.

Ordered the parts from Carlsen Audi...

Part    Dealer cost     Carlsen Cost
4 pin   $97             $46
Knock   $85             $56
        ____            ____
        $182            $102

Hmmmm....sounds like a deal to me!  (and these came in the Bosch boxes too!)

Changing the 4 pin was tricky but only took about 5 minutes.  You can't get
a wrench in there, so I had to use the trusty old "Vise Grips (tm)" to get
it out.  Gotta love brass threads, as a little tug after maneuvering the
grips and the sensor just popped lose.  Had the new one handy...unscrewed
the old one to the very last thread (no coolant loss yet), and unscrewing
the last thread started the coolant "glugging" out.  However, it took about
2 glugs before I got the new sensor in and the loss was MINIMAL.  A little
more smirking and worrying with the vise grips and the sensor was tight.
Watch the orientation of the connector when you reconnect it as the old
connector from the harness is very brittle and breaks with the slightest
pressure in the wrong spot.

The knock sensor is right on the block in fairly plain view...easy to get a
wrench onto.  Turns out that the bolt that held in the sensor was
LOOSE...VERY LOOSE.  Just tightening it would have fixed it, but I figured
it would be better to just put the new sensor on and not worry about it.
Torquing is "critical" as it says in Bently.  I tried my best to hit 7
ft-lbs, but who knows what it is as my 1/2" drive beam wrench only reads in
5 lb increments, and my 3/8" torque wrench only goes down to 20 ft-lbs.  Oh

1st improvement...I have a temperature gage again!!!!!  My overheat/low
coolant light is indeed low coolant.  I'm losing some somewhere, so that's
my next project.

2nd improvement...the engine pulls much smoother now.  No stumbling, no
hesitation...go figure!  Damned computer has probably been in "limp" mode
for a while, eh?

3rd improvement...the A/C doesn't seem to cycle short anymore.  I know the
A/C is tied to the 4 pin sensor, but might also be controlled by the
computer based on knock (ie. engine loading).  Don't know if this is
tangible as I haven't run it with the A/C on very much since that time, so
I'll have to make it a point to check it.


 +---------------------| _   /| |---------------------+ Opinions expressed
 |   Chris Ice, CMfgT  | \`o_O' | Allen-Bradley Co.   | are mine and don't
 |   CMIce@mke.AB.com  |   ( )  | 1201 S. Second St.  | reflect views of my
 |   (414) 382-2136    |    U   | Milwaukee, WI 53204 | employer.  So there!
 +---------------------|  Ack!  |---------------------+
  Amiga 2000/030@33MHz  --------  1988 Audi 90 Quattro