[urq] Hot Start Problems Continued...

[DGraber460 at aol.com]

In a message dated 5/2/2006 9:52:14 A.M. Mountain Daylight Time,  
james.pasqualoni at gs.com writes:

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






I have been wondering that myself but have had no luck finding any experts  
to shed light on that idea. I would think there has to be. I don't think octane 
 boosters will work, and their expensive.
 
Any chemical engineers out there?

I have a fuel gauge I could send you to check fuel pressures before you  
spend money on parts. You could check the full warm operating pressure- shut the  
car off, and check for rate of pressure loss. Then you would know for sure if  
either the injectors or check valve is leaking. I have checked mine many 
times,  and it holds longer than the spec in the IST documents. 
 
Dennis  Graber
5605 S. Helena Court
Aurora, Colo. 80015
303-690-1231  home
720-838-0558 cell