type44 rough start and rough idle when cold.. CO off? any

[JordanVw at aol.com]

turn key, and car fires right up most times on first try, sometimes have to 
try twice.  but no "long cranking" is necessary.   but immediately when it 
fires up, it idles like crap, around 4000 rpm.  i then shut it off, and recrank 
it, it fires up, and idles fine for about a minute.   then 4pm's drop back down 
really low all the sudden.  it will continue to idle like crap, until car is 
driven and warmed up.  i dont need to keep my foot on the accel to keep it from 
stalling - it wont stall, unless i rev the rpms up, and then let off on the 
accel- then it will stall from rpms dropping so fast.  like i said it does this 
in the summer as well as winter.   its been doing this for like 6 months now. 
   does this tell you anything else?
thanks
chris
86 5kt

In a message dated 1/13/05 2:18:59 PM Eastern Standard Time, 
syljay at optonline.net writes:


> >
> > its not intermittant, it starts like this all the time when car sits for a
> > period of over 5  hours or so..  basically it does this every morning
> weather
> > its minus 10 out or 100 degrees out.    but it doesnt do it when the
> engine is
> > warm.
> **** Aha! Now we are getting some good symptoms.
> 1. Normal operation when engine is warm.
> We can eliminate most vacuum leaks
> Difference between cold and warm operation is the cold start injector, and
> the temp sensor that tells computer how to adjust fuel mixture for various
> temps.
> 
> 2. Test the cold start valve for proper operation.
> Injector gets 12 volts on startup, which opens the injector during engine
> start. This is your "choke".
> Do you have the Bentley manual? The manual will tell you how many seconds of
> spray vs ambient temperature.
> 
> 3. Define the symptoms again for a morning start?
> a. Long crank times?
> b. Sounds like it tries to start?  One or two cylinders try to fire?
> c. a + b, and then it starts up, but idles real rough, you have to keep idle
> at high RPM otherwise it dies?
> d. c, and after warm up the engine idles fine and you have no more problems?
> c. Does it start right up, and after a few seconds it dies, wont idle?
> 
> 4. Has the engine ever run right? How long have you had these symptoms?
> 
> >
> > what "bonnet yellow plugged nipples" are you talking about?   vacuum line
> > plugs?
> ****Right!
> The "bonnet"( big rubber hose gizmo that connects fuel distributor to the
> throttle body at the intake manifold) is the name in the family album for
> this molded rubber hose/gizmo.
> The yellow plugs in the bonnet plug off various vacuum "bosses" that are not
> used in your model.
> These "bosses" are convenient places where you can spray in starter fluid,
> or connect a hose from a propane tank.
> 
> Your problem sounds like a fuel mixture problem when cold. Most likely
> failure is the temperature sensor that tells the computer how to adjust the
> fuel mixture. The sensor is "set"(broken at) to warm and thats what the
> computer sees all the time. When the engine is already warmed up, this is
> not a problem. When the engine is cold, the computer is setting the fuel
> mixture for a warm engine and this mix is too lean to properly start and
> idle.
> 
> Another area that will give you similar problems is the system fuel
> pressure. Not enough pressure equals not enough fuel in the mixture - you
> are running lean. Engine will run when warmed up, but starting with this
> lean mixture is a bitch.
> We just diagnosed Denis's problems down to the fuel pressure regulator. Some
> dork monkey lad prior to Denis buying the car had replaced the fuel pressure
> regulator with the wrong part number - 60 PSI instead of 90 PSI. The car
> started and ran, but marginally.
> 
> But, lets get you to define the symptoms in more detail - see 3. above.  It
> will narrow down the possibilities.
> 
> SJ
> 
>