4KQ: No power to thermo-time switch after cranking

[R Mangas]

>The thermo-time switch/cold start valve only gets power during cranking,
>so that's completely normal.

   Are you sure about this?  IIRC, the implication in the bently is with a
correctly operating system and cold engine you should get 2-10 seconds of
voltage at the CS valve after cranking.

   I just got done messing with this system on my 87 4kq, Russ, and I don't
believe the voltage at the thermo-time switch originates in the starter but
rather in the ECU.  (could be wrong, the elec diagram in the bently isn't so
hot on this).  Regardless, after screwing with it for about a week and a
half, incorrectly diagnosing the problem as a bad TTS ($80, ouch!) I bought
a pushbutton yesterday at Radio Shack and now have a manually controlled
cold start valve.  It's what I should have done from the outset :(

Robert




>From: Ti Kan <ti at amb.org>
>To: rinard at execpc.com (Russ Maki)
>CC: quattro at audifans.com
>Subject: Re: 4KQ: No power to thermo-time switch after cranking
>Date: Sat, 22 Feb 2003 13:51:25 -0800 (PST)
>
>Russ Maki writes:
> > On my '87 4000 quattro, I get plenty of current in the cold-start
>circuit --
> > as long as the starter is cranking. Once the engine fires (which it does
> > almost immediately) and I let off the starter, voltage to the cold start
> > valve drops to zero and I have to nurse the gas pedal to keep it
>running.
> > Could my starter solenoid be defective? If so, my local rebuilder has
>some
> > 'splainin to do.
>
>The thermo-time switch/cold start valve only gets power during cranking,
>so that's completely normal.  Your after-start problems are caused
>by other ailments, not the cold start circuit.  I would check the
>coolant temp thermoswitch that feeds the ECU, and the usual CIS
>troubleshooting stuff.  Use your Bentley manual as your guide.
>
>-Ti
>2003 A4 1.8T multitronic
>2001 S4 biturbo 6-sp
>1984 5000S turbo
>1980 4000 2.0 5-sp
>--
>     ///  Ti Kan                Vorsprung durch Technik
>    ///   AMB Laboratories, Sunnyvale, CA. USA
>   ///    ti at amb.org
>  //////  http://www.amb.org/ti/
>///
>


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