Coil wiring seems wierd.

[thumpar]

So I am changing to pertronix ignition and coil. There were 2 wires on the + side of the coil. I removed them and traced them back and found 1 goes to the back of the starter and assume this is from the ballast resistor. The other wire goes to the front of the engine just under the valve cover to what I am assuming is the temp sensor.

This seems really odd to me. So now do I take the wire from the back of the starter and feed it straight battery power and put the wire that goes to that sensor back where it was on the old coil (which doesn't sound right to me) or do I connect the 2 wires that where on the coil together, put the wire back onto the back of the starter and run a new wire from ignition + to the coil?

TIA

Edit: Forgot to mention this is an '83 merc 120.

 

[bruceb58]

Re: Coil wiring seems wierd.

On the positive side of the coil, the one wire that goes to the starter connects to a post on the solenoid that allows the coil to get full voltage during cranking. The other wire will go to the ballast resistor.

 

[thumpar]

Re: Coil wiring seems wierd.

Ok I found that what I thought connected to the sensor on the front is not. It was a false from my meter because it beeps on more that connected. I think the wire runs to the back of the alternator but not sure. I measure just under 6 ohms from battery + to that wire with the key on. So now I am in search of the ballast resistor.

 

[cheburashka]

Re: Coil wiring seems wierd.

What color are the wires on the coil? My '74 had two whitish wires, and the wires themselves were the resistor.

If you're using the Pertronix, you don't need to keep the ballast resistor. You can get rid of your original coil and install one that doesn't need an external resistor. Then bridge directly from the post on the solenoid to the positive terminal on the coil. I did that on mine and it greatly improved the idle and hot-starting. The Pertronix system doesn't need the lower voltage that you get from the ballast resistor.

 

[thumpar]

Re: Coil wiring seems wierd.

I am installing a pertronix coil with the system. That is what threw me off. I went to bypass the resistor and can't find it.

 

[Fishermark]

Re: Coil wiring seems wierd.

As mentioned, the wire IS the resistor. It is a resistance wire. You can find the wire coming from your ignition switch and tap into that - preferably after the main engine wiring plug so that you can still just disconnect the one plug when pulling the engine.

 

[thumpar]

Re: Coil wiring seems wierd.

Ok now it all makes sense. Thanks for the replys everyone.

 

[Coors]

Re: Coil wiring seems wierd.

As mentioned, the wire IS the resistor. It is a resistance wire. You can find the wire coming from your ignition switch and tap into that - preferably after the main engine wiring plug so that you can still just disconnect the one plug when pulling the engine.

therefore the 6 volts.

 

[thumpar]

Re: Coil wiring seems wierd.

I figured out the whole reason I was getting confused. When I was checking between the choke + and battery it showed a 5 ohm resistance. Check a schematic and this was not right. Went to the ignition switch. No resistance there. Found an inline fuse just after the ignition and popped it open. It had some rust on it and was the resistance that was showing up.

It actually was a good thing I quess. I have learned alot about the wiring on this thing. Might save me a tow or using the oar to get back home some day.

 

[Coors]

Re: Coil wiring seems wierd.

di-electric grease everything.