200 QA No Start problem SOLVED!

[Michael, Dave]

So this weekend I suffered from, diagnosed and fixed the no start
condition in our 1990 200 QA  (card would crank and crank but not
catch). The ironic part is that I found part of the answer in a reply to
a posting I made (!!) regarding the SAME PROBLEM I had about 10 years
ago! The reply was from none other than Scott Mockrey. It was (as
expected), usefull enough to I think bear reposting:

My original question:

	Well, the audi gods should be truly embrassed that my reliable,
allways start no matter how cold it is mode of transportation is 12 year
old Alfa Romeo Milano with 150,000 miles.... The hard start situation on
my car has developed into a no-start situation. This morning, it was 25,
and was in the teens overnight, The car didn't even think of starting.
Its a 1990 200 qw. I checked a few things: diagnostic self check runs
fuel pump, cold start valve and all other valves. LED test lamp
connected to cold start valve connecter lights for ~4 seconds while
cranking temp sensor ok at 3kohm Plugs look pretty dry last week I
checked: System pressure ok @ 87ps Control pressure ok @ 15psi @ 32F air
flow plate rest postion ok air flow plate free play ok sensor plate to
air cone clearance ok once all the gunk was cleaned off - but maybe
still not ok at cold temps idle speed and co setting both needed
adjustment - the freq valve was cycling down to 100% duty cycle every 10
to 15 seconds. I reset every thing, and then it idled fine. 

Scotts reply:
	>Dave wrote: >idle speed and co setting both needed adjustment -
the freq valve was cycling >down to 100% duty cycle every 10 to 15
seconds. I reset every thing, and then it >idled fine. If you saw a very
high duty cycle at the freq valve, this is indicative of a vacuum leak
in the system. You should never have to adjust the mixture that much
from the original adjustment with a correctly sealed intake/breather
system. This assumes the adjustment was not fooled with by someone else
and the fuel distributor plunger movement is smooth and it is not
sticking. Have you checked the following:

	replaced the fuel injector inserts and o-rings? 
	checked the back side of the main breather hose? 
	check underneath the rubber Tee fitting at the valve cover? 
	checked the breather hose from intake boot to valve cover tee
fitting? 
	Replaced the valve cover gasket? 
	Accordion hose at intercooler? 
	Intake pipe rubber connection at Turbo? 
	Turbo exit hose? 
	Idle Stabilizer valve hoses blown off slightly? 
	Dipstick and oil cap gasket? 
	Sticking Decel valve behind r/fender (pretty rare) 
	Cam or Rear main seals? (less likely) 
	One other thing, did you pull the cold start valve and watch it
spray into a bottle during the output test? If you had the gauges
connected, you could also watch for a pressure drop when the cold start
valve is briefly actuated with jumper leads. My 89 200TQ would not start
the other day in 20F weather, I had to jumper the cold start valve to
get it to fire up. I was using a spare ECU that had a dead transistor
for the cold start valve circuit. The ECU output test confirmed it was
not getting grounded by the ECU. I am embarrassed to say I have been
driving it around this way for several months! It always started when
the temps were above 40F. HTH Scott Mockry 

Back then, the problem was a dry/leaking valve cover gasket and injector
seals. This time it was a rotten rubber breather hose (and old cap and
rotor). 

The moral of the story? Vacuum leak, Vacuum leak, Vacuum leak!

Hope that helps

Dave
90 200qa 210 k
98 m3/4 89k
02 mcs 19k