Long cranking on 5kt...

[Phil Payne]

> I went to diagnose a problem I've been having with my
> '86 5kt for a while now, and I'm a bit confused.  I
> thought there'd be a good chance that it's the cold
> start that's causing my problems, but the Bentley
> manual seemed to indicate that the thermo-switch only
> operates below 20C.  The problem is that ambient temps
> are higher than this and I have the problem.

Don't think it has ANYTHING to do the thermoswitch.
 
> If I run the car for a while and shut it off, it start
> almost immediately.  The idle is reasonably smooth,
> and I don't there's there's any large vacuum leaks.
> 
> Once upon a time it would start before making one
> complete rotation.  It was actually a bit weird how
> quickly it would catch at times.
> 
> Thoughts on where to look?  My first guess would be
> the cold start valve, but Bentley seems to indicate
> that it's not even needed above 20C.  If infact it is,
> what normally fails?  Where is the thermoswitch
> anyway?
 
Classic residual pressure leakdown symptoms.  Pull all of the injectors (including the cold start valve) and dry the ends thoroughly with paper towels.  Then jumper the fuel pump for a few seconds and watch what happens to the injectors when you turn it off.  If any ends get moist, replace the injector.

If none get moist, replace the non-return valve on the fuel pump.  If that doesn't fix it, it's the system pressure regulator.  If you have the internal one (inside the metering head) it's a $30 kit of parts from Audi - the external one is $$$ but taking it off and pushing a thin rod up the end opposite the thin hose attachment to free up the plunger has worked at least once.  There's actually an adjustment up there (3.5mm or 4.5mm Allen, I can't remember) that Scott Mockry found but it's best to leave it alone if you don't have fuel pressure measuring equipment. 
____________________________________________
> Do You Yahoo!?
> Get personalized email addresses from Yahoo! Mail
> http://personal.mail.yahoo.com/




_______________________________________________________________________
FSmail - Get your free web-based email from Freeserve: www.fsmail.net