Hmmm. Does it have capacitor or diode protection? Capacitor types have a
stepped cover over the points and can be used on either +ve or -ve ground
cars. Diode types have cover that isn't stepped, have an X in the part
number, and are polarity sensitive, there being +ve and -ve ground versions.
Even though the diode types are polarity sensitive they *will* work connected
the wrong way round but the diode points protection is rendered largely
ineffective and the points can be expected to fail fairly quickly.
So ignoring the protection device the circuit is very simple, 12v is applied
to the terminal sticking through the cap to the 'in' side of the points, which
should be closed, the 'out' side of the points connected to one of the
solenoid wire, through the solenoid, the other solenoid being connected to the
body of the pump under the cap, and there should be a ground spade on the body
of the pump near the diaphragm flange which is connected to ground. There is
also a swamping resistor inside the pump across the solenoid windings which
aids points protection but like the diode and capacitor protection it can be
ignored as it doesn't stop the pump working if it has failed ... until the
points are knackered of course.
So check you have 12v on both sides of the points, if it is only on one side
they are not closed properly, being either out of adjustment or still dirty.
Then check you have 12v on only the points side of the solenoid winding, if
you have it on both sides it is not grounding. If that is OK disconnect the
voltage and measure the resistance of the solenoid winding, I'd expect to see
something in the low teens of ohms, but Dave Dubois could give a more accurate
figure. If much higher than that the implication is that the solenoid winding
is faulty. If not, then it *should* be working.
PaulH.
----- Original Message -----
From: James Schulte
To: Paul Hunt
Sent: Monday, November 08, 2004 9:26 PM
Subject: Re: MGC restoration nearing completion need help on some small
problems
Paul,
Cleaned the points with no luck.
Jim
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