Hot start

Mark Woodland markwoodland at
Wed Dec 4 13:51:30 EST 2002

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!

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