Overdrive troubleshooting help.

Low voltage? I believe the paul has to be shoved down to engage the sun gear, maybe needs all 6 volts? Also, possibly has developed a weak ground?

The first thing you do when OD gives a problem is to check out the output of the generator. The generator feeds the electrics to the overdrive. You must have 6.7 volts to 7.2 and at least 20 amps. Battery does not feed OD. Walt.

Richie, what precisely is the problem? When you push the knob in (to enable overdrive), then get up to roughly 30 mph and release the accelerator, it does NOT click into overdrive? Yet it continues to free-wheel?



If this is the case, I'm curious: when you push the knob in, is there any clearance between the back of the knob, and the "stop" (the plate in which the knob shaft runs)? Or does the knob bottom out against the plate?

Park is far more knowledgable on the single lever transmission OD wiring than I am. But, you mentioned in your first post about the governor having 5 wires going to it. That seems very odd to me, it should have only one - and it should be a ground.



The solenoid has two hot circuits in it. A heavy "Pull-in" coil that has a very heavy amp load to it, and a "hold in" coil that is self activated by the plunger movement. The heavy Pull-in coil is only supposed to be hot long enough to place enough pressure on the lock up pawl to move and engage, once its made its stroke and the OD is engaged, this movement is supposed to actuate a set of contacts internal to the solenoid and switch the amp load from the pull-in to the hold-in windings. It sounds to me like your "hold-in" coil is staying energised and the amp load is blowing your 30 amp fuse. I don't know how much amperage the pull-in coil is supposed to draw, but it was never meant to be a constant load on any circuit in the car.



I seem to think you have two problems going on. The high amp load of the pull-in coil requires a much better ground than the hold-in coil. All of the problems I've had with the OD system stem from the quality of the grounds. The lock out switch and the governor are subject to get oil in them and interfere with the grounding quality of their contacts. I wouldn't surprize me if perhaps your solenoid is suffering from the same oil related problem and has disabled the "hold-in" contacts.



Park also gave a real good lesson on installing the OD solenoid a few years ago. If its not installed correctly, it can't make a full stroke and would cause the internal contacts not to operate also.



I hope some of that helps you. I'd chase the grounds and contacts from the governor back to the OD relay first, then focus on the solenoid. Park and I disucssed the Solenoid's amp draw a few years ago by e-mail, but we never did put a number on the amp draw of the two solenoid coils. In a properly switching circuit, the amp draw of the pull-in just bounces the amp meter and it settles at the hold-in amperage.



One more item on OD setups that your mopar buddy Pete aka "blueskies" ran into. There is another set of contacts in the solenoid that run to the point side of the coil. Upon Kickdown, the kickdown switch will close a ground circuit through a set of contacts in the solenoid, effectively grounding the igntion circuit and by-passing the points. When the solenoid makes its upstroke to disengage, it breaks these points and full voltage goes back to the distributor. If you remember, he fused the ignition circuit and everytime he "kicked-down" it would blow that fuse and his car would die. The amperage spike caused by the direct short would blow his fuse and kill the ignition circuit. This direct shorting will also kill a Pertronix unit absolutely dead - never to arise. The addition of a normally closed relay to complete the ignition hot side and opens through the former kickdown ground will fix that problem and keep a Pertronix unit isolated from a direct ground.



Mark

Richie, I've made some tests since Hudsonator and I talked some time back. The pull-in coil on your solenoid should draw 20 amps, so shouldn't blow a 30A fuse. You might have a bare spot on one of the two wires going to the solenoid. Check those wires closely. Or there could be a fault in the solenoid that's grounding the pull-in circuit somehow. Remove the solenoid cover and look closely at the wiring inside. Oil on the internal contacts for the pull-in coil wouldn't cause this ... if those contacts don't "make," the solenoid won't pull in. Try this: push the OD button full in. Rig a hot wire with a 30A fuse in the circuit, and a separate short jumper wire. Disconnect the normal wires at the solenoid. Use the short jumper wire to connect the hot wire to the hold-in terminal on the solenoid. You shouldn't hear anything happen. Now momentarily touch the end of the main hot wire to the pull-in terminal. You should hear the expected "clunk." Now remove the hot wire from the pull-in terminal. You should hear nothing, since the hold-in coil is doing its job. Now remove power from the hold-in terminal, and you should hear the clunk as the solenoid "drops out." And of course, the fuse shouldn't blow during this procedure. If all happens OK, the solenoid is likely not the problem.



On the Pertronix issue, Pertronix told me years ago, in response to my query, that grounding the "distributor side" of the coil will not harm their unit. A Dixie Chapter friend wired his Hornet that way and never had a problem. Of course they may have changed something such that the earlier guidance isn't valid any more..