Message text written by INTERNET:Crazeecooter@aol.com
>I have been having emission problems with my TR6 so I decided to replace
my
emissions canister (1974 TR6)...and noticed that there are two wires
hanging
about down there that are not connected. One is black (ground?) and the
other is brown with a yellow stripe. These wires are stemming from the
same
section of the harness that also has a white wire with grey? stripe and
purple and ? stripe colored wires that are going to the deal right under
the
emissions canister. (this thing (name?) has got a big black hose
connecting
it the emission canister) Anyway...if any of you are with me so
far...should these unconnected wires have a home? Could this be part of my
problem??
<
Jonathan,
This is the anti-run-on valve. Probably the most misunderstood component
on the late model TR6's. The valve is fed power from the keyswitch only
when the keyswitch is in the off position. The other terminal on the valve
solenoid coil is grounded through the oil pressure switch but only when you
have oil pressure. The net result is that when you switch off the running
engine a circuit is made and the valve is activated but only as long as
there is oil pressure. So when the engine stops and the oil pressure goes
away the oil pressure switch will opent he circuit and the valve is
switched off.
On the pneumatic side the valve switches vacuum from the manifold to the
charcoal canister which, in turn, applies this vacuum to the float bowl
vents which will suck the petrol away from the carburettor jets starving
the engine of gas rendering run-on a virtual impossibility. Hence the name
anti-run-on valve.
If you check the oil pressure switch you will find a wire that matches the
color of one of the wires you found. The other wire comes from the
keyswitch. I do not have my manual with me and don't know the wire colors
but if you look on page 17 of the Bentley (don't quote me on the page
number but if you look in the front of the book instead of the electrical
section in the back you will find a diagram for the later cars which will
show this circuit) you should find the wire colors there.
Good luck
Dave
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