powering the coil

[Omie01]

OK, I think I have all my wiring back to stock on my 1972 with Tach and tri-pod cluster. I'm going to try to get all the wiring right this weekend. I am not using the stock coil/breaker points. I have a pertronix 1, and flame thrower 1.5 coil. My questions are these.......Does the red/light green on the engine harness go to the coil? Is this the resistor wire? Which side of coil does it hook to? pos/neg? If I want a full 12v to my new coil, do I source it from the "I" side of solenoid? Where does the tach get its signal, and where does it hook to? At the junction block for ammeter, does that hold the black/orange from main harness, and the black from the alternator? I know this is a lot of questions, but this car had some fried wires and I don't want to repeat history. Does anybody have a clear pic of their solenoid and coil wiring I could see? ANY help would be greatly appreciated!!

 

[Don C]

If you do a tach wiring search of this forum you will find what you need, posted by Wolverine in 2012, with a nice wiring diagram.

Because of the way the tach is wired in-line with the coil you cannot use 12 volts to the coil. You need to get RocketMan's tach conversion to be able to do that.

 

[jeff8877]

Here is the diagram Don referred to...

http://www.7173mustangs.com/attachment.php?aid=11538

 

[jbojo]

If you do a tach wiring search of this forum you will find what you need, posted by Wolverine in 2012, with a nice wiring diagram.

Because of the way the tach is wired in-line with the coil you cannot use 12 volts to the coil. You need to get RocketMan's tach conversion to be able to do that.

+1

If you look in the data section of this forum you will find the wiring diagram for your car.

In short when you turn the key to the start position +12v is sent from the starter solenoid to the coil and its at full voltage. Once the car starts the coil gets its pwr from the Tach because the key is then in the run position. Pwr then comes from the ignition switch to the tach and then to the coil. I believe there is a resistor wire inline that drops the voltage some to the coil for normal operation. The 12v is provided initially to help the car start but if 12v is used continuously it would burn up the coil so Ford designed this method.

I am using RCCI's tach conversion and it works perfectly. Here is his instruction.

http://rccinnovations.com/Instructions/StdTach.pdf.

So with the tach conversion the two wires that originally go to the tach right now you splice them together (I jumper'd them together so that I didn't alter the original wiring) and bypass the tach completely and use the original connector at the coil (+ side of the coil). Then you just need to route two additional wires (red/Green in the diagram) to complete the setup. The new red wire must be connected to a 12v switched on the fuse box.

Side note: The RCCI tach conversion is really accurate. My MSD ignition box sends out a reference signal of 6000 RPM for 4 seconds and this tach is spot on. With my old tach it would sometimes hang and was probably not very accurate. With this set up it looks completely stock.

 

[Omie01]

OK, thanks guys, what about the ammeter junction block? That gets the black from alternator, and black/orange from main harness? My black from alt may have been black and orange at one time, but I bought the new alternator harness from CJ's, and its only black.

 

[Don C]

If you wire it any differently than in Wolverine's sketch the tach will not work. I believe if you use a volt meter you will find that the junction block is hot all of the time. The Pertronix module has to be wired to a key-on hot wire.