hesitation / bog down

[Steve Sears]

Hayes,
You might also want to check the deceleration valve, if it is sticky and 
activated while driving it'll make the engine die.  Another thing that makes 
a sudden death feeling happen is a flaky fuel pump relay.  Hayes, I'm sure 
you'd be all over checking and reflowing the soldered connections on a fuel 
pump relay, huh?
For a MityVac, Princess Auto has one on sale occasionally.
Cheers!
Steve Sears
1987 Audi 5kTQ
1980 Audi 5k
1962 and '64 Auto Union DKW Junior deLuxes
----- Original Message ----- 
> From: Brett Dikeman <brett.dikeman at gmail.com>
> Subject: Re: hesitation / bog down
> To: hayes myers <hayesmyers at gmail.com>
> Cc: quattro at audifans.com
> Message-ID:
> <9d9c4a330912111136t2fea3823xb707b1340bc1dc3f at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> On Fri, Dec 11, 2009 at 1:41 PM, hayes myers <hayesmyers at gmail.com> wrote:
>
>>  let off and revs fall off like it's going to die.
>
> Classic signs of bypass valve failure, at least on the 20v's; the dead
> giveaway is when the report is of the engine idle dipping or engine
> dying coming off a freeway exit ramp.  It's almost always the cause
> for that exact symptom.  Don't the late 10v MC2s have bypass valves
> too?
>
> If you've got a mityvac, disconnect the control line from the intake
> manifold and apply vacuum.  The problem can be either the control line
> cracking, or the valve diaphragm tearing.  It's a $50-ish part, so
> definitely test before you replace.
>
> If the valve is fine (or you don't have one)- maybe check that the
> metering plate moves smoothly?
>
> Oh, also, is the ISV clean and working smoothly?  If it's gummed up,
> it can stick in a position where it is almost completely closed.
>
> Brett