XR700 Ignition Wiring Diagram

[bartman]

Does anyone have the correct wiring diagram for a Crane XR700 Wiring Diagram for my 1973 240Z?

My car came with one installed, and it seems to be working alright, but I can't get my tachometer to work. I don't know if the tach is fried, or it's just hooked up wrong.

[Bambikiller240]

Try the Crane Cams website. Usually that stuff is usually available for download.

[bartman]

I tried the website and downloaded their instructions with diagrams, but they don't have one specific for the Z. One of the things different on mine is that the positive coil wire for the ignition system is connected to the ballast resistor instead of the coil. Is this correct? Also why doesn't my tach work?

[bartman]

I was able to find an ignition wiring diagram at http://zhome.com/ZCMnL/tech/ZXPertronix.htm. There are stock diagrams as well as diagrams for a Pertronix Ignition, and a ZX electronic ignition. I also used the diagram in the XR700 documentation I found at the crane website.

One of the differences was that my electron ignition was wired to the ballast resistor instead of the coil. I changed this and the tach still didn’t work. Another thing I noticed was that the tach seemed to work while my engine was cranking but not after it started. According to the information I found and these diagrams, the difference is that while the engine is starting the ballast resistor is bypassed. After the engine starts the ballast resistor is used.

I finally discovered that the person that installed this unit added a wire from the ballast resistor to the positive side of the coil. As soon as I removed this wire everything worked, including my tach. I am still using the old positive loop tach, and now it works great. I can only assume that the flow was going through the ballast resistor straight to the coil instead of flowing through the tach.

[Bambikiller240]

The very same Stock and Pertronix diagrams were available to you here, on this website in our Technical Articles forum:

http://www.classiczcars.com/forums/showthread.php?t=10538

You originally asked for an XR700 Diagram which we don't have. Had you asked for a Stock diagram or a Pertronix diagram we could have saved you some effort.

[bartman]

Reading through this post it looks like maybe I should put the RED wire from my Crane XR700 back to the Ballast Resistor. It seems to work either way. Any thoughts?

[Bambikiller240]

bartman:

Only 2 thoughts I have are:

1. Wether the ballast resistor is used or not is dependent on the coil you are using. If

the coil needs a resistor and you don't run one, the coil will die fairly soon, so if you don't know what your coil needs, I'd run it "with" the resistor in the system.

2. I used to have an XR700 on my car, but HATED it so much that I tossed it and the instructions in the trash, and installed the Pertonix.