Dean C. Paige <ecopaige@metro.net> writes:
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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
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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.
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