89 100 ISV Diagnosis

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <7D2FA48EBD3BD1118C2400A0C981D8C913BF05@www.cbsi.com> "Powell, David" writes:

> David, your assumptions about needing a new Idle Stabilizer Valve
>  are correct.  After purchasing an ISV over the weekend,
> and taking about 5 minutes to clean it up, and another 5 to install it,
> your car should work just fine.

>> 1. Have I done all that I could / should to diagnose my problem?

I think I'm with both Davids on this one.
   
>> 2. Is there anything else I could do to bring the ISV back to life?

As far as I'm aware, the long soak on carburettor cleaner is about it.  These 
things are usually fairly easy to find in junkyards. 

>> 3. Have I forgotten to ask any other relevant questions? (catch all
>> plea for help)

Only thing that might catch you out is that the controller will _NOT_ drive the 
ISV after the connector has been pulled off the latter until the ignition has 
been switched off and on.  Also, it's a current-operated device and shouldn't 
really have 12V put across it - at a nominal 8 ohms and 430ma, about 4V is a 
good test.  Twelve volts produces 1.5A - three times the nominal current.  I 
have a modified camera release containing two 1.5V batteries - it produces a 
noticeable click and movement from a good ISV. 

This is the official test for the ISV from the socket in the left footwell for 
the MB engine - yours is very likely similar:
 

           ==+====+==                          ==+====+==
             |    |                              |    |
  +----------+----+------------------------------+----+----------+
  |                                                              |
  |   +--+    +--+    +--+                +--+    +--+    +--+   |
  |   |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
 UK Audi [ur-]quattro Owners Club