Re: the continuing cold start valve saga (solved, I think)

["Wm. Josiah Erikson" <josiah@gsinet.net>]

Heh... no, mine's an 8v. I figured it out. My thermo switch was screwy, so the
cold start valve was only operating tentatively. Now I have a good time
thermoswitch. What I didn't understand was why the thermoswitch had a terminal
50 wire on it. Now I understand- it's to heat up the thermoswitch so that the
ground goes away when you crank the starter too long.
It is all clear to me now! (in case anyone cares)

So, is this right? :
1. The cold start valve operates when it gets positive current from one side
(terminal 50) and is grounded out by the time thermoswitch on the other side.
2. The thermoswitch green/white wire is grounded to the block when cold,
floating when hot.
3. The thermoswitch white/red wire is there to activate the electrical heating
element in the thermoswitch so that it will heat up and cut off the ground to
the cold start valve when you crank the starter too long. This is to keep the
engine from flooding.

I think we should write to Bentley and tell them of this mistake. My Bentley
has it all wrong, too. Brian, is yours correct? (Mine is old as well- made in
'83, it covers '80-'83 Rabbit/Scirocco/Jetta including Pickup Truck,
Convertible, and GTI). Maybe they already fixed it at some point.

I'm glad to be all clued in now, and thanks to Brian and Andre for helping me
out! (Now I can truly understand that fuel enrichment module thingy)...
    -Josiah

A. Bjorkheim wrote:

> > The cold start valve operates under what conditions?
>
>     Operates when the temp of the motor is below 95F, usually.  Or
>   until the element in the thermo-time switch is heated to 95F.  I
>   guess the usual time it takes to heat to that point is 8 seconds.
>
> > (which
> > terminal/terminals getting voltage/ground).
>
>     Both the thermo and cold start have 2 wires.  Each one has a red w/blk
>   wire that is connected to terminal 50.  Terminal 50 is the one that is
>   connected to your starter solenoid.  Once you engage the starter
>   solenoid, both the thermo and the cold should get voltage in that red
>   w/blk wire.  The other wire that is on the cold start is the same wire
>   that goes to the thermo.  The 2 units are connected via that wire.  In
>   my case it is green w/wht. This wire controls the ground for the cold
>   start.
>
> > What does the thermo time switch do to shut it off? Supply it with
> > ground? Voltage?
>
>     To shut off the cold start, I think the green w/wht wire goes
>   from grounding the cold start to floating, meaning it is just hanging,
>   not connected to ground or 12.6v
>
> > When the
> > thermo time switch is cold, should it have continuity or not?
> >
>     Well, I think my thermo is bogus so I cant give you accurate readings
>   as far as ohms goes, but I would think that if you measured the
>   resistance between ground and the terminal on the thermo, the terminal
>   for the green w/wht wire, it shoudl read very minimal ohms.  This is
>   because when the engine is cold the cold start needs to have a ground.
>   Once the car warms up, the resistance between the body and the same
>   terminal on the thermo, the one for the green w/wht wire should now
>   be infinite, theoretically.
>
> > My car is currently thus:
> >
> > The thermo-time switch appears to be open when cold. (It has a bunch of
> > resistance across its terminals, but not infinite). BOTH terminals of my
> > cold start valve plug are getting battery voltage when the starter is
> > operated. My cold start valve IS operating. One terminal of my thermo
> > time switch is definitely grounded permanently. WTF? How does this
> > system work? The Bentley is completely unhelpful, as it contradicts
> > itself several times. I don't get it!
> >
>     Hmm, strange.  Is yours a 16v?  I know they make diff thermo-time
>   switches for 8v and 16v so that could be it.  Perhaps yours operates
>   that way, but mine needs to have one wire of the cold start grounded
>   for it to operate.  All I know is my Bentley contridicts itself by
>   telling me to jumper my thermo, but in another section it says to
>   insert a test light into the cold start plug.  Well, if you are doing
>   the tests and you want to bypass the thermo by jumpering the terminals,
>   you will now have both wires as hot, at least in my case, and thus the
>   cold start wont work and the light wont come on.  Brian Hannold pointed
>   out in his 1980 Bentley that nowhere in there does it say to jumper the
>   thermo.  I can only think that the 8v thermo is different from the 16v
>   thermo in that way.  All I know is I need a new thermo cuz when I
>   ground the green w/wht wire on the cold start, the engine starts right
>   up.
>
>   Andre'
>   Neon Green 79
>
> Am I a guru on this subject yet  =)
>
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