I got a 70 XR-7 351W auto trans an I had a guy I know change the plugs an plug wires on the car. When he got done the black connector that goes into the threaded end on the solenoid was off. I hooked it back up an now you have to plug the black connector in to the solenoid for it to get power an start the car then unhook it to keep the starter from wanting to keep trying to start. it did not do this before the plugs an plug wires were changed. I changed the solenoid & getting ready to change the starter everybody tells me sounds like something might be hooked up wrong or a bad ground. Could either one of those cause this problem?