The whistling 20V, testing the Hitachi unit

[Steve Sears]

Tom,
You mean you used "Throttle Body Cleaner", NOT "Carb cleaner", right?
The ISV's essentially come in 2 flavours - 2 wire and 3 wire.  If you can
blow air through an unpowered 2 wire unit, it's leaking.  When powered by a
9 volt battery, it'll make an audible click - check to see if a polarity
switch will make a difference.
Clean it with TB Cleaner, NOT Carb Cleaner - the latter will dissolve the
seals in the ISV.
Cheers!
Steve Sears
1987 Audi 5ktq
1980 Audi 5k
1962 and '64 Auto Union DKW Junior deLuxes

----- Original Message ----- 
> From: TWFAUST at aol.com
> Subject: Re: The whistling 20V, testing the Hitachi unit
> To: quattro at audifans.com
> Message-ID: <9f.5b789e1f.2f72ef4c at aol.com>
> Content-Type: text/plain; charset="US-ASCII"
>
> I pulled my ISV to clean and bench test ('90 90 20VQ). It didn't seem
dirty,
> but I used carb cleaner anyway. While disassembled, I hooked up a 9V
battery.
> Not sure what was supposed to happen, but I expected motion from the
> "plunger". What I got was nothing. What is the correct test procedure? I
ran test leads
> to the terminals on the ISV. I hooked up my DMM to the test leads and got
> approximately 9 volts. Since there are two terminals, I assume there is no
need
> for a ground.
>
> Interesting aside, the HItachi unit indicates the car is a '90 rather than
a
> '91. It was a Rhode Island car and cars that old don't have titles.
>
> My local boneyard has several 90 20VQ's, never thought to look ay what ISV
> they have. Will later units interchange? Can the "motor" be grabbed off
another
> model ISV?
>
> Tom Faust