I am installing a edelbrock pro flo 4 in place of the old pro flo 1 system. I had everything wired and I turned the key to start, engine started, I realized i needed to turn off engine to program the ECU. Turned the key off and engine kept running. I am using the IGN terminal for the source power for the system. I have a old harness and wiring diagrams and I discovered the pink wire from the IGN switch powers the right hand side of the gauges fuse slot and a small wire leaves from the left hand side to feed the gauges. I removed all the fuses with the cable still on the IGN terminal and engine would turn over but not start (expected since fuse was removed). I moved the source power cable over to the right hand side of the gauge fuse slot, car started and turned off when key was moved to the off position. I know the small pink wire from the IGN terminal feeds a lot of things. It seems like I am getting voltage back on the small pink wire which will not allow the engine to shut off when the key is turned off. I unplugged the gauges from the cluster, no change. I removed the fan speed wire, no change. I know where most of the items are that are fed from that small pink wire. How can I go about testing these to determine where my back feed is coming from. I am not sure how the neutral safety switch can be tested. I do have a meter to help in diagnosing issues.

 

update - I put the gauge fuse back in and moved the cable to the IGN terminal, started car and stopped car with the key. Started adding the fuses back and when I added the turn/rev light fuse the engine would not shut off. After looking at the schematic I believe the neutral safety switch is the only common device on those 2 circuits. Is there a way of checking the NSS to be faulty short of just replacing it?

 

I believe the alternator will feed the gauges circuit while its charging. Try unplugging the 2 wire connector at the alternator to confirm.

 

I have a one wire alternator and I unplugged it, engine still did not shut off. I have another NSS I will try tomorrow. Where in McHenry are you, I have family in Richmond.

 

Close to the outdoor theatre. Got friends in Richmond too.

 

In the event someone has this issue here is the resolution. After replacing the NSS problem still present. Both reverse lights would not come on. Determined the ground connection in the socket must have been corroded. I wiggled both of the ground connectors and both lights came on. Engine starts and stops with the key now. Will take the ground off the socket and clean it thoroughly. Its crazy how a bad ground in the reverse lights can put voltage on the ignition circuit.