Embarassing wiring question


New Member
Jun 18, 2001
I recently installed the speed pro system in my car. I also determined that my alternator was toast. so I replaced it. Nothing more than bolt on and plug in. the alternator is working fine. The problem is that the car will start fine and run fine but when I turn the key off, the car keeps running. The only change I have made to the car is the addition of the fuel injection. all of the lugs on the ignition switch are hot when the car is running and I turn off the key. It is like the alternator is back feeding the ignition somehow. It worked fine when I had the carb on it. I have to disconnect the ignition feed wire to kill the engine.

just wanted to know if anyone else ran into this problem before I start hunting an electrical gremlin.
Engine Run On

What you have described is fairly common when using a master battery disconnect per NHRA/IHRA rules. The easiest fix is to buy a kit from Painless Wiring, for about $40, from Jeg's or Summit.
What do they call the kit? Does it replace the Master disconnect set up I am currently using?
Charging System Shutdown Relay

The name of the kit is above, and it is made by Painless Wiring. Jeg's part number is 764-50103; it retails for $37.99. It does not replace your master disconnect switch, rather it works with the switch to keep the alternator from back-feeding power for the ignition. I had the same problem you describe on my car and the kit fixed it. Good luck!