Listers,
I have had a nagging problem which I have finally decided to try
correcting this upcoming weekend. So I am looking for pointers in case I
need to get some parts in advance. (Car is a 76 TR6, basically stock).
Problem: My oil pressure light (the yellow indicator on the tach) glows
when I first turn the ignition to the on position. The ignition light
(red indicator on the tach) also glows. This is normal behavior. When I
start the car, both lights go out. Oil pressure goes to normal and I can
drive away. All is still normal at this point. Now I shut the car off. I
do not hear a click from the anti-runon valve as I expect. Further, if I
now turn the key to the On position (but don't crank the starter), the
ignition light glows but the oil light is off. The oil light should be
on at this point.
I have replaced the oil pressure switch with a new one. Behavior is the
same. I can short the wires which lead to the anti-runon valve (black
and white/purple I believe) and this will produce a click from the
valve.
I have yet to test the output of the switch with a meter in the above
described situations to see if that changes between the starting from
cold state and the starting from warm state. My (crude) analysis of this
leads me to think that either I have two faulty oil pressure switches or
something in the block where the switches connect to (an oil gallery???)
is behaving differently when the engine is cold than when the engine is
warm (or recently run). Could the gallery be getting plugged when warm?
Or is something making the switch think it still has >5psi pressure when
I shut off the engine? If so, what could cause this?
I have not yet tested the anti-runon valve when the engine is warm so
this too could be a problem.
If anyone has any suggestions on what else I might be overlooking I
would greatly appreciate your suggestions. Specifically, I wonder how I
can confirm that the anti-runon valve is functioning correctly? Just
shorting the black and white/purple wires when engine is warm seems
sufficient to me, but I am not sure.
(I have cleaned the contacts on the anti-runon valve so I know that part
of it fine. The contacts on the oil pressure switch and harness are also
clean.)
Looking forward to your ideas,
Peter Zaborski
76 TR6 (CF58310 UO)
Calgary AB Canada
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