[urq] Hot Start Problems Continued...

[Pasqualoni, James E]

Thanks Dennis.  Are there any additives that can be mixed with the fuel at
fill-up to raise the boiling point back up again?


  _____  

From: DGraber460 at aol.com [mailto:DGraber460 at aol.com] 
Sent: Tuesday, May 02, 2006 11:45 AM
To: Pasqualoni, James E; r0ssat0_987 at att.net; urq at audifans.com
Cc: pkrasusky at ups.com; sportscar at gwi.net; Bill.Perron at otis.com
Subject: Re: [urq] Hot Start Problems Continued...



In a message dated 5/2/2006 8:32:21 A.M. Mountain Daylight Time,
james.pasqualoni at gs.com writes:

Urq.  Yes, that is my suspicion and why I ordered one a few months back.
Just have to install it now.  I hope that's all it is!

Thanks. 

-----Original Message-----
From: r0ssat0_987 at att.net [mailto:r0ssat0_987 at att.net] 
Sent: Tuesday, May 02, 2006 10:31 AM
To: Pasqualoni, James E; urq at audifans.com
Cc: 'Perron, Bill'; 'pkrasusky at ups.com'; 'Sports Car Workshop'
Subject: Re: Hot Start Problems Continued...

Which car is this on, UrQ or 5kq?  My first bet is the check valve at the
fuel pump.


-------------- Original message ----------------------
From: "Pasqualoni, James E" <james.pasqualoni at gs.com>
> The Symptoms:
> When cold, car starts immediately upon cranking.  Runs great with no
issues.
> Idle is strong and steady at 850 rpm.
> 
> Hot Starts:
> When attempting a hot start, after the car has been sitting for a few 
> minutes, it immediately catches, stumbles, then stalls.  Car will 
> continue cranking with good spark, but there appears to be some vapor 
> lock or flooding-not sure.  No strong smell of gas at all.
> 
> What's Been Done:
> -New 85 deg C injector cooling fan thermo switch.  Injector cooling 
> fan works fine -New vacuum thermo switch (the one on the block near 
> the ig distributor -Checked for vacuum leaks-none found
> 
> What should I pursue next?  I was leaning towards fuel pump check 
> valve, then injectors.  Does this make sense?  I don't believe that 
> there are any vacuum leaks, however, I will keep checking this as well.
> 
> Thoughts, suggestions, please?
> 
> TIA,
> Jim




The check valve is not expensive and _might_ cure it, but if your area has
started to put more ethanol in the fuel, which many areas are doing, you
will probably get vapor lock with all systems functioning to spec. The
alcohol lowers the boiling point of the fuel below the threshold of what the
system was designed for some 20 odd years ago.
I put a manual switch to my cold start valve, which if operated briefly will
get it to fire enough to lift the air plate, purge the air, and start the
car. Since it is electrically opened and not pressure operated it allows for
the air bubbles to purge.
I would bet that if you manually run your fuel pump you will hear the vapor
bubbles "boiling" back into the tank via the recirc line.
Many listers still don't believe me on this issue, but that matters not.
Empirical evidence is what it is.
 
Dennis
Denver