My electrical problem on my 1971 XR7 convertible is that the charging system isn't charging the system! I installed a brand new wiring harness, coil, alternator, battery, voltage regulator, and still can't seem to keep a charge. I am at a loss as to where the leak could be. I believe everything is installed correctly. Also, I am having tachometer problems in that when I start the car, the tach reads 500 RPM, which is normal idle speed, but when I go to accelerate, there is not one bit of movement from the tach needle. I have a feeling that the tach is required to work in order to complete the ignition circuit. It is in fact in working order, just not properly. Now, prior to installing the new coil, the tach worked perfectly. Does anyone have any tips or hints as to what I can do to resolve these issues? Other than that, this car is almost a daily driver with only 30,000 original miles on it.