Al:
The wiring at your oil pressure switch is buggered, resulting in your
anti run on valve being engaged all the time. The anti run on valve should be
powered ONLY when the ignition is off and there is oil pressure (i.e.
the engine has just been turned off).
When the wires on the oil pressure switch are swapped, there is
power to the anti run on valve all the time. It overheats, and applies
vacuum to your carb bowls at all times, leaning out the mixture.
There are three wires on your oil pressure switch. In theory, that
means there are 8 possible combinations, but only one works correctly. There
is absolutely NOTHING to keep you from buggering the wires, as the connectors
are all identical, and not keyed in any manner. Unless you write down
which wire goes to which terminal when doing maintenance, you have an
88% chance of mis wiring it when you hook it back up.
When I purchased my 74, the DPO had miswired the oil pressure switch,
and apparently gave up trying to figure out why the valve was on all the
time. He simply disconnected the leads to the valve and twisted on a couple of
wire nuts to insulate the dangling wires. His solution for courtesy
lights that wouldn't turn off was to remove the light bulbs. Obviously,
the DPO was not a rocket scientist.
Cheers,
Vance
PS. The oil pressure switch may be bad, but this is unlikely.
Checking it with a meter does not yield the results one would expect,
so it is easy to conclude (erroneously) that the switch is bad. Be
absolutely certain that your wiring is correct before replacing the
switch, as you may replace a perfectly good switch. Ask me how I know.
-----Original Message-----
From: owner-6pack@autox.team.net [mailto:owner-6pack@autox.team.net]On
Behalf Of Paula J. Graffam
Sent: Saturday, November 01, 2003 2:31 PM
To: 6pack@autox.team.net
Subject: End of Trouble Shooting
Listers,
Here were my symptoms:
* Cold engine start would stall with choke fully pulled out
* At full acceleration in 3rd, 4th and 5th gear @ approx. 4k rpm
engine
would flatten out and buck.
Here were my fixes:
* Professionally relined the gas tank
* Installed all new hoses on fuel line from front to back
* Installed new fuel pump and replaced fuel filter
* Installed a three way fuel valve recommended by Jay Welch just for
kicks
* Rebuilt both carbs. and blew air in all the appropriate places
Here is the result: nothing really changed !!!
Here is my one last idea:
* Plug up the vacuum hose that goes to my inoperative anti-run on
valve.
( Note: the valve, newly installed from Moss, developed an
electrical short
in the unit and was draining my battery. The valve
was extremely
hot to the touch with the leads on it so I disabled
it. It was about
this time I started having symptoms.)
Here is the result:
* One handy old sheet rock screw on my workbench installed in the
vacuum
hose has solved the #^%$&#& problem!!!
Here is my question:
* Why???
Regards,
Al Graffam '74 CT
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