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ISV question from new member/owner



In message <34D730DD.E4383E38@cgrams.com> Keith Simpson writes:

> Anyway, I have what appears to be the "common high idle problem" 
> So I have unplugged the ISV and have run a few months using a lot of
> heel/toe to keep from stalling at lights when the motor is cold. 
> I guess I am just a cheap b*******, but other than the
> inconvenience,
> is anyone aware of any other downsides to this mode of operation?

A few.  Have you done the ISV socket diagnostics?  The ISV does quite a few 
useful things, including deliberately raising idle when battery voltage is low 
and when the vehicle is moving.


           ==+====+==                          ==+====+==
             |    |                              |    |
  +----------+----+------------------------------+----+----------+
  |                                                              |
  |   +--+    +--+    +--+                +--+    +--+    +--+   |
  |   |16|    |13|    |10|                | 7|    | 4|    | 1|   |
  |   +--+    +--+    +--+                +--+    +--+    +--+   |
  |                                                              |
  |   +--+    +--+    +--+                +--+    +--+    +--+   |
  |   |17|    |14|    |11|         [ ]    | 8|    | 5|    | 2|   |
  |   +--+    +--+    +--+                +--+    +--+    +--+   |
  |                                                              |
  |   +--+    +--+    +--+                +--+    +--+    +--+   |
  |   |18|    |15|    |12|                | 9|    | 6|    | 3|   |
  |   +--+    +--+    +--+                +--+    +--+    +--+   |
  |                                                              |
  +--------------------------------------------------------------+

(Contact 5 is chassis ground.)

       Tests with a DC voltmeter:

14 + 5 - ignition on - Power                        Battery Voltage

14 + 1 - ignition on - Code input B                 Battery Voltage

8 + 1  - ignition on
         throttle closed
         idle switch closed                         Battery Voltage

       Tests with a diode test lamp:

17 + 5 - engine running - RPM from ECU              Diode must flash

7 + 5  - ignition on    - road speed sensor
         left front wheel turned by hand            Diode must flash

       Tests with an ohmmeter:

13 + 5 -                - thermoswitch              800 to 1000 ohms
                                                    at 20c, 70 to 150
                                                    ohms at 80c

11 + 4 - ISV attached   - ISV resistance            3 to 8 ohms

       Tests for cars with air conditioning:

6 + 5  - ignition on    - E87
         air conditioning on                        Battery Voltage

2 + 5  - ignition on    - N25
         air conditioning on                        Battery Voltage


-- 
 Phil Payne
 Committee Member, UK Audi [ur-]quattro Owners Club