Max,

You don't give a whole lot of information, and a problem like this usually needs
some troubleshooting, BUT here are some things that could be going on.

1.  Old spark plug wires-when damp, they will allow the high voltage to leak out
so that the spark you deliver to the plugs is very weak.  And, when starting is
when you need the hottest/strongest spark.  Solution would be to replace wires,
and possibly cap and rotor.

2.  Dead or faulty cold start injector, aka the "the 5th injector", or with a 5
cylinder Audi, the "6th injector".  The CSI is an electric injector in the
intake manifold whose purpose is to fire briefly during cranking to squirt some
raw fuel into the intake to help with cold starting.  If its not working, a
significant part of the cold start system is awol.

3.  Bad one-way valve at the fuel pump.  What this does is prevent the fuel in
the fuel system from flowing back through the pump and into the tank when the
pump isn't running.  That way, pressure is held in the system for quite a
while.  When this goes bad, the pressure in the injector lines drops quickly. 
Not really a problem with the cold start, but it can certainly lead to a lot of
vapor locking and very poor running for several seconds after a hot re-start. 
But, I have seen these go bad and lead to difficult cold starting, too.

4.  Intake air leaks? 

5.  Worn out or misgapped spark plugs?  That would definitely lead to a hard
cold start.  Be sure to use anti-seize lubricant on the threads if you replace
them.  And don't use platinum anything or Autolites. 

As Auntie Rita suggests, there could be problems with the fuel, but I really
doubt it.  I've never had any problems with old fuel or laquer or anything like
that, although I guess its possible.  But, I suspect something else.

Oh, another potential problem is a bad coolant temperature sensor.  It could be
that its failing and the computer thinks the engine is warmer than it really is
and isn't richening the mixture properly.  Or, the warm-up regulator (WUR, aka,
control pressure regulator, or CPR) isn't working correctly.  In that case,
though, the engine would likely run very poorly until it warmed up, if at all,
in addition to the hard cold starting.

Its very unlikely to be the oxygen sensor since there's no signal from them
until the engine has some heat in it.  Or, said another way, the computer
doesn't even consider the signal from the ox sensor until the engine has warmed
somewhat, usually at least a minute after it starts, possibly up to 2 minutes or
more.

Auntie Rita, the temperature rating of the spark plug refers to how hot the
nose, the ceramic bit around the center electrode, runs.  Colder plugs run
colder and hotter plugs run hotter.  The hotter the electrode runs, the better
it is at burning the carbon fouling off of itself and keeping itself clean.  So,
if your engine tends to burn a bit of oil, then a hotter plug will keep from
fouling itself so much.  BUT, a hotter plug is a hotter plug, so if you have a
tendancy to detonate, or ping, then you want your combustion chamber to be as
cool as possible to prevent premature ignition of the fuel/air charge.  The
hotter the plug, the more likely the hot ceramic causes premature ignition, so
that's why you DON'T want as hot a plug as possible.  But, for cold starting,
the temperature range of the plug has no effect.

Good luck with it!  And be sure to let the list know what you find out!

Regards,
Ben Pender
Klassic Autos
Vintage European Auto service, repair, and parts
Madison, AL
256-489-9560


--- On Sun, 11/30/08, Max Hoepli <mhoepli@...> wrote:
From: Max Hoepli <mhoepli@...>
Subject: [Audi Owers USA] Starting Problem
To: audi_owners_usa@yahoogroups.com
Cc: w-t_audifans@yahoogroups.com, quattro@..., urq@...
Date: Sunday, November 30, 2008, 3:03 PM











Hi all,



Starting engine with 1986 Type Turbo Quattro, sometimes when left for longer

time in cold weather the car has to be cranked for a long time, 4 cranks

each 10 seconds, then car puffs and puffs and runs. Mechanic told me it has

something to do with air intake, and sensors. Ignition is not problem

according to him. He once used a T-shaped Allen screw to remedy problem. If

temperature is 5C+ there is no problem.



Any comments?



Max



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