Petronix ignition issues

[Dave]

Anyone ever install the Petronix ignitor 3 on our trucks? My app is a 71 BB, mostly stock.There's a resistor wire somewhere that causing a voltage drop to the coil between 6-9 volts during start up. The ignitor needs a constant 12 volts to work properly. Anyone run into this before? LMK, thanks Dave.

[LockDoc]

Originally Posted by Dave

Anyone ever install the Petronix ignitor 3 on our trucks? My app is a 71 BB, mostly stock.There's a resistor wire somewhere that causing a voltage drop to the coil between 6-9 volts during start up. The ignitor needs a constant 12 volts to work properly. Anyone run into this before? LMK, thanks Dave.

There is a resistor wire that runs from the ignition switch but I don't think it is in the start circuit, it is in the run circuit for non-HEI distributors. If you need a constant 12 volts to the coil or ignitor when the switch is on you can run the power wire to the "IGN UNFUSED" terminal on the fuse block.

LockDoc

[VetteVet]

The resistor wire you are talking about comes from the firewall block and runs to the stock ignition coil where it joins a yellow wire from the starter R terminal. The yellow wire gives the coil a full 12 volts during startup and then the resistor wire feeds the coil with reduced voltage during normal running.
You have a couple of options here. You can run a new wire from the fuse panel on the ign unfused terminal like Doc says or you can remove the resistor wire from the firewall block and run a wire from there to the pertronix unit.

Here's a picture of the resistor wire, It's the cloth covered one and it was orange purple and white from the factory.



Here is a diagram of the stock resistor wire shown by the red arrows.

[Dave]

Wow, thanks guys, I appreciate the info! I checked my wiring and I don't have the resistor wire described, however, I will be running a seperate wire from ign unfused. I'll take some pics tonight.
Vet, where did you get a color schematic?
Thanks again Dave.
Posted via Mobile Device

[LockDoc]

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The electrical diagrams are available in the Thread/Thread Starter area of the electrical forum.

http://67-72chevytrucks.com/vboard/s...d.php?t=185856

LockDoc

[Wrenchbender Ret]

Check the Petronics instrucktion sheet. Some of them use the resistance in the circuit. Mine does.

[VetteVet]

Be careful of the coil too. I bought a shiny chrome blaster coil but it was 3.8 ohms resistance which is made for the six cylinders and the v-8s use the 1.8 ohm coil. I don't know what the difference is but they said it won't work with the v-8.
It must be in the resistance value and using a ballast resistor.

[GASoline71]

Originally Posted by Wrenchbender Ret

Check the Petronics instrucktion sheet. Some of them use the resistance in the circuit. Mine does.

The Mallory I installed in a rig I had eons ago needed a ballast resistor too. So it all depends on the application. But a stock GM HEI needs a constant 12v.

The MSD Pro Billet HEI I have in my rig now needs a 12v constant.

Gary