deville 67 abrupt stalling

[TomB]

Hi all,

Nasty experience, probably caused by the transmission downshift switch. While driving the car regularly stalls abruptly. When engine is running and I ever so lightly touch the square shift coming out of the transmission downshift switch(?) engine stops immediately. Shop manual mentions angles and a lot of tech gibberish that is incomprehensible. Anyone familiar with this and able to explain what to do? See picture with red arrow pointing to the square shaft

Pretty scary experience on the highway...

Thanks a lot for your insights.

Tom

[cadillactim]

Maybe an issue with your switch pitch torque converter and/or switch pitch solenoid inside transmission. Unplug the switch and see if engine quits stalling. You will have no downshift though.

With engine off, key on, slowly move the accelerator linkage. You should hear two clicks; one for the switch pitch solenoid and the other for the downshift solenoid.

There is a diode in the wiring at the switch that goes to the coil bracket. It is a ground circuit. Maybe the switch is acting up too.

Bruce is the switch pitch guy, maybe he will chime in.

Tim