Re: Cold start valve/thermo time switch testing (cold starting problems)

[Brett Van Sprewenburg <brett@netacc.net>]

It was already there. :)  Been there for at least 4 months or so...

==Brett


>Looks like a good write up to put on Scirocco.org.
>
> >>> "Andre' Bjorkheim" <andreb.mail@gte.net> 09/22 7:28 PM >>>
>Helpful test for checking functionality of the cold start and the
>thermo time switch unit.  I believe its applicable to both Mk1 and Mk2
>roccos.  This came about because the 75-79 Bentley had the incorrect
>procedure (regarding wiring) for testing the cold start unit.  Perhaps
>this will help some of you listees in fixing your cold start problems.
>
>    If you have a meter, some wire, and basic tools you can do it ALL
>the cold start/thermo time switch testing yourself.
>
>  First thing I would suggest is running an extra ground wire from
>where the cold start bolts up to either the chassis or the battery
>ground itself.  On my Mk1 its not necessary, but for some reason I
>have heard that it is a problem with the Mk2 cars.  Also clean your
>battery ground cable and where it bolts up to the battery and also the
>chassis.
>
>  Second, if you have a multimeter you can test to see if both the
>thermo time switch and the cold start are getting power when you
>crank the engine over.  To do this, simply remove the 12 guage wire
>(red w/blk stripe) off of terminal 50 on the starter.  This is the
>wire that gets power when you crank the car over.  Also remove the
>plugs on the thermo time switch and the cold start valve.  Take the
>multimeter and check for continuity between the 12 guage red w/blk
>wire that goes to the starter solenoid with the red w/blk wires
>that go to the cold start and thermo time switch.  In each case,
>you should read close to 0 ohms.  If either of those red w/blk
>wires that goes to the cold start or thermo time are busted, then
>they arent getting power on cranking, and hence cold starting will
>be a problem.
>
>  Next, if those wires check out okay, you will need to check the
>continuity between the green w/white stripe wire.  This wire is
>connects the cold start to the thermo time switch.  When the car
>is cold, the thermo time switch grounds that wire so the cold
>start will then fire.  If the circuit is open, the cold start will
>never fire.
>
>  Next, if that wire checks out okay (roughly 0 ohms resistance)
>then you will want to check the operation of the thermo switch
>and cold start valve themselves.  To do so, simply take the meter
>and read the resistance between the one spade terminal on the
>thermo switch that corresponds to the green w/white wire and the
>engine block.  When cold (recommended you do it in the morning)
>this resistance should be very low, if not zero.  When hot it
>will read a few hundred ohms or more.
>
>  To check the operation of the cold start, simply ground the
>green w/white wire (keeping the plug attached to the cold start
>while grounding the green w/wht wire from the thermo time switch
>plug) and try to crank the engine over.  If everything is peachy,
>meaning the cold starts red w/blk wire had power and the green
>w/white wire is properly grounded) and the car should fire right
>up.  If not, then the cold start isnt functioning.  If it
>doesnt fire right up, you can take the cold start off the
>end of the intake manifold, place it into a jar, remove the
>12 guage red w/blk wire from the starter solenoid, place a
>jumper wire from the battery + into the red w/blk wire and
>then jumper L13 and L14 where the fuel pump relay sits (or
>terminal 87-output and 30-power on where the relay sits), and
>you should get fuel to spray out.  If not, then your cold
>start is faulty.
>
>  I hope this solves your cold start problem.  And, if I missed
>anything, I hope someone points it out to me.  Good luck...
>
>==============================================
>
> André Bjorkheim
> Lime Green 79 Scirocco ©
> ICQ #76283458
>
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>
>
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 \/  '84 Scirocco (ITB racer 2B) | "Hot VW's, take two home. They're small"
\/\/ '88 Scirocco 16v (Show), '85 Scirocco (Winter) | - brett@netacc.net

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