FW: Hot start

Livolsi, Stephane Stephane.Livolsi at investorsgroup.com
Wed Dec 4 13:54:31 EST 2002

It's a small world after all.....

That is exactly the system I have in my car - 86 5KTQ, which I originally
installed to work around a... drum roll please.....hot start problem!

I have since cured the hot start problem, unfortunately I can't give any
advice because I don't know what fixed it.  It seems to have been cured
after replacing the multi function temp sensor, but I can't be positive
because I did other stuff at the same time.  During my diagnosis of the hot
start problem, I hot wired the fuel pump to ensure system pressure and that
did not help at all.  I ran the fuel pump for a few minutes before cranking
and still no hot start.  Push my cold start button and vroom.  I think Mark
might be onto something with his compressable column of air theory.
Actually, the more I think about it the more I am thinking he is bang on!

Anyway, I still have it hooked up, just in case.  Works like a charm anytime
I want a little extra starting insurance, either hot or cold.

Just use a momentary contact switch and not a regular rocker switch.  That
way it will shut off as soon as you remove your finger.

> ----------
> From: 	Mark Woodland[SMTP:markwoodland at hotmail.com]
> Sent: 	December 4, 2002 10:51 AM
> To: 	jeffrey_audi at hotmail.com
> Cc: 	quattro at audifans.com
> Subject: 	Hot start
> Jeff,
> I'm just getting a handle on this with my '87.
> Still not 100% diagnosed, but the workaround (for now) is to mount an
> under-dash switch ($3-$5)that will allow the cold start injector to be
> grounded at will. This will not only prime the car when hot, but will
> purge
> the air (vapor lock) from the fuel system. My best guess-to-date is that
> the
> cold start injector is leaking slightly after shutdown, just enough to
> allow
> a compressable column of air to keep the rest of the injectors from
> breaking
> over the pressure threshold to start spraying. Its cheap enough to check.
> I'm guessing the Cold Start injector is leaking because I've already
> replaced all of the other injectors.
> The blue/black stripe wire on my '87 TQ is the +12 that comes on when
> cranking/running, and the plain blue wire is the ground that only
> "grounds"
> when the temp switch sees the head at or around 80 degrees F. If you
> control
> the ground, you've got it knocked. Just turn it on long enough to
> prime/purge/start, then turn it off, or the car will run waay too rich.
> (Might be helpfull under full boost 8^P  )
> (Unless, of course, you have a vacuum leak, or any one of a handfull of
> maladies that the TQs are heir to.)
> If I had figured this out earlier, it would have saved me numerous
> no-start
> horrors, calls to AAA, hitch-hikes in stupid-cold weather, and plaintive
> wails from the family...
> Funny you should mention.. I was just getting ready to go outside and
> install the under-dash switch on mine now. I've already tested the
> concept,
> and was just going out to make it "offical" before the snow flies here in
> frigid PA.
> Give it a shot and let me know how you make out.
> Best of luck!
> Mark
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