Re: Are these overdrive problems?

Posted by HH56 On 2012/8/18 10:11:30

There are 3 sets of contacts in series preventing the ign circuit being active except for the brief instant it's needed -- one in the solenoid and two in the relay box. If one set is hanging or out of adjustment, there could be enough overlap to cause an issue.

With no OD selected or locked out, 2 sets should be open preventing any problem. Wiring would be the only way ign would be shorted.

When at speed and ready for OD, ground from governor and thru interlock switches goes to the main relay & closes a large set of contacts to power the solenoid. As that relay main set closes it also opens a smaller set in the ign circuit. Simultaneously because the solenoid has power, the other relay closes it's set in ign circuit. When the solenoid is powered and in the process of moving pawl into mesh, at about the 2/3 or so point of plunger travel it's set closes. All stays in that condition until kickdown is made -- 2 sets closed, one open.

When kickdown is made, immediately the main power relay drops out closing it's small set and ign circuit is complete. Engine misses, and with power cut and torque low, the solenoid plunger releases. The closed solenoid points will open somewhere toward the last 1/2 of travel and the second relay set will open after a small delay to ensure the circuit is open in case the plunger is mechanically slowed for some reason. That entire operation shouldn't take more than a few milliseconds or as the book says a "few" ignition pulses.

As far as wiring, the wires from solenoid 6 to relay 6 and relay 2 to the coil are the ones to check. If the solenoid hasn't been opened, it might be a good idea to check and dress those contacts and make sure the phenolic insulator button separating the light and ign contacts is in good shape. The relay box could also be opened to verify the condition of those contacts as well.