David Massey wrote:
>
> Dean C. Paige <ecopaige@metro.net> writes:
>
> <<<<<<<<<<<<<<<<< Snip >>>>>>>>>>>>>>>>>>>>>>>>
>
> 73 TR-6. Have'nt encountered this before.
>
> Battery has been running down last couple of weeks. Apparently anti run
> on valve escarpment is remaining switched on (closed?) after the engine
> is switched off. My understanding is that the oil pressure switch has
> control over this valve - oil pressure up = valve closed = vacuum
> maintained. Oil pressure to zero = engine off = valve open = vacuum lost
> = no run-on. My conclusion - oil pressure switch malfuntion maintains
> circuit closure after oil pressure drop. Closed circuit drains battery.
> Have I got this right? Any other suggestions on testing the theory befroe
> buying new o p switch.
>
> Dean
> <<<<<<<<<<<<<<<<< End Snip >>>>>>>>>>>>>>>>>>>>>>>>
>
> You got it about right. When the key is switched to the off position
> a special terminal supplies +12 volts to one side of the solenoid
> on the Anti-Run-On valve and the oil pressure switch provides the
> ground connection for the other side of the coil - that is as long as
> there is oil pressure. When the oil pressure drops to zero the switch
> opens up and the solenoid is de-activated (saving battery charge).
>
> Cars with this configuration have a special oil pressure switch. This
> switch was three (3) terminals. One terminal is connected to ground
> (black) wire. One of the other terminals is used for the Anti-Run-On
> valve as described above. This terminal is connected to the ground
> only when there is oil pressure.
>
> The third terminal is for the oil pressure failure warning light
> (on the dash). This is the typical oil light set up and this part
> of the switch works exactly opposite from the section described above
> (ie: it is connected to the ground only if there is NO oil pressure)
>
> If your Anti-Run-On valve stays activated all the time and it is not
> a recent occurance then I would first check to see if the switch is
> not just wired wrong (very easy to do since the terminals are not
> marked. I had to figure out mine with an ohm meter which is easy to
> do if you happen to be an electrical engineer (like me).
>
> Here is how mine is wired up:
> There are three terminals, two terminals are parallel to each other.
> The third terminal is at a right angle to the others. The Three
> terminals form a semi-circle. The wires are connected in the
> following order going in a clockwise manor: black, white/brown,
> white/grey.
>
> Hope this helps.
>
> Dave Massey, St. Louis, MO, USA
>
> P.S. The Anti-Run-On valve works by applying engine vacuum to the
> float bowl chambers which pulls the fuel away from the jets thus
> starving the engine making Run-On impossible. Thats what the two
> extra tubes going to the carbs are for.
Thanks David. I understood the principal of the operation of the anti
run on valve well. However being an Environmental Biologist by education
sometimes the electric throws me. This in spite of the fact that I took a
year of physics. I'm also acquainted with the oil pressure switch design.
BUT, I did have the wiring disconnected from the switch while putting on
a spin on oil filter adapter. May have reconnected improperly. No ohm
meter so I'll try reconnecting in the configuration you described and see
what happens.
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