Can you run electronic ignition with overdrive. I seem to be blowing the module when I ground out the OD to get out of OD. Sent from my VS996 using The H.A.M.B. mobile app
Shouldn’t be doing that I have been running electronic ignition for about 4 years on my 51 merc with flatty and od.no problem yet.
The solenoid is a large electromagnetic coil - I suspect it is sending a large voltage spike into your wiring when you ground the coil (think of it as an oversized ignition coil). Something funky going on with your wiring for the spike to reach the electronic ignition. NOTE: electronic ignitions are susceptible to ground problems.
IIRC, someone else had that problem with an electronic ignition. I don't remember if it was here or elsewhere. I think the solution involved putting another relay in, but I don't remember the particulars.
Yes, you need a relay.... The way the OD wiring is normally configured is that power is supplied to one side of the coil and the other side is connected to the points. The points switch the ground on and off, producing spark. When you tromp on the gas pedal to shift out of overdrive, the wire from the OD switch shorts the distributor side of the coil to ground, interrupting the ignition to unload the trans. Once the solenoid has shifted, it opens a contact and removes the short, re-establishing ignition. Here's a typical diagram with points... The problem is the electronic module switches power, not the ground, so it doesn't like being shorted to ground... as you have discovered. Here's the fix... You'll need a 5-pin relay with both a NO and NC contact. The existing power to the module remains, but extend it to the relay and connect it to the 85 terminal. The module wire that did go to the coil should be connected to the 30 terminal. Connect the 87A NC terminal to the coil where the module connected. Last, connect the wire from the kickdown switch to the 86 terminal. The 87 NO terminal isn't used. Sequence of operation is in normal driving, module power to the coil is supplied through the de-energized relay. When you tromp the gas and close the kickdown switch, the ground is supplied to the relay and the NC contacts open, disconnecting the module and unloading the trans. Once the trans has shifted, it opens the relay ground circuit and the relay loses power. The relay closes and power resumes to the coil.
Contact Petronics to be sure but I think their recommended fix is aresistor. But I don’t recall the value or circuit location
We did something wrong. We took the red Petronix wire and connected to ignition and continued to 85. Took the black wire and connected it to 30, then ran wire to positive side of coil from 87A. We end up with no power to coil. Should we take red wire to 30 also and black wire to negative side of coil? I just don't want to blow up the module again, already blew 2 up.
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