89 100 NF cold start injector problem (long)

[John Gourley]

My 89 100  non-quattro 2.3 NF  seemed to be running extremely rich at idle.
After some checking I discovered the cold start valve was operating full
time, whenever the ignition was on.  As I understand the system, the valve
gets it's ground thru the FICU to spray fuel while cranking and cold.  I
checked the ground wire from the cold start valve to FICU pin #16 to find it
was grounded all the time.  My wiring diagram shows that brown wire going
directly from the cold start to FICU #16 pin.......shouldn't be grounded all
the time.
I ran an outside wire from the cold start injector to pin # 16 on the FICU
and tried that.............I had the injector removed and on top of the
manifold where I could watch it (spraying into a container).........after
running this direct ground wire to the FICU, the cold start injector worked
correctly, spraying only while cranking BUT the problem with this
connection.......the engine will not start!  I have tried several things but
basically it acts like the cold start injector is connected in series and
when disconnecting any of the original wiring it will not start.  this does
not make sense because the diagram shows the ground wire directly to the
FICU and no where else......it shows the green/red power wire coming into
the injector after a connection of several green/red wires going to the idle
stabilizer, frequency valve, idle and full throttle switches as well.  This
doesn't make logical sense to have it either spray fuel all the time the
ignition is on  (not while cranking, just on, or the run position) or to
make a temporary direct ground to the FICU, letting the injector function
properly but not starting.
Once the ground wire connects to pin #16 , how does it get the ground to
cause the injector to function......
that is, what all does it go thru in the FICU to get a ground while
cranking?

I made another temporary connection.........completely bypassed the original
wiring to the injector, brought a power wire from the # 50 cranking
circuit........this would start right up, run for 5 seconds or so and shut
down.  then go back to the original wiring and it would start ok but start
"blubbering" at idle or lower rpm's because it was spraying constantly from
the cold start injector.

when I disturb the original green/red and brown wires to the cold start
injector, and make some temporary connections getting the injector to spray
only when it should,  it acts like I am somehow losing #15 current from the
ignition........altho that may be a wrong guess.......back to the drawing
board!

anyone run into anything like this?

thanks!!

John  Gourley
toycraft at theriver.com