Fuel injection problem (?)

[quk@isham-research.demon.co.uk (Phil Payne)]

Roger Galvin's 'new' 1989 Coupe quattro (KV engine, non-turbo, 60k) has become 
_very_ difficult to start when cold.

Roger called out the RAC, who fiddled with it for two hours and then flat-
bedded him home (ca. 210 miles).  I had a play with it, and following Roger's 
suggestion that it was a fuel-related problem, checked the system and control 
pressures.  System is about 5.4 bar, which I think is low but not low enough to 
be a problem.  Control is 0.4 bar when cold, which I think is _definitely_ a 
problem.  CPR is as per Fig. 5-3, page 6-16 of Probst.
 
I jumpered the fuel pump (and thus the control pressure regulator - same 
circuit) direct from the battery and control pressure slowly (we're talking 
continental drift here) rose to 2.8 bar - at this point we were able to start 
the engine and control pressure eventually reached 3.1 bar.  The car was driven 
50 miles, stopped, restarted after four hours and driven home.
 
A replacement CPR has been ordered.

This morning, it wouldn't start again.  I repeated the above trick and got to 
a control pressure of 2.5 bar.  No dice - the engine wasn't even vaguely 
interested.
 
Two questions:

a) Has anyone BTDT?
 
b) The fuel metering head is _different_ yet again.  This time, instead of
   a casting for six ports with one not drilled out, it's a real six-port
   head.  Five of the ports are connected to the normal injectors - the 
   sixth feeds the cold start valve.  I've never seen an arrangement like 
   this before.  Does anyone have any experience/tips to share?

-- 
 Phil Payne
 Committee Member, UK Audi [ur-]quattro Owners Club