MSefi.com read only forum (Jan.15,2018)

Hi everybody, I have a 70 Nova, BB, that I recently converted to port injection, I'm running a DYI V3.0 board, along with a relay board for all the engine bay connections. I just recently put this together and the car starts and idles good, the issue I have is when I turn the key to off the engine continues to run! I'm sending my switched 12V to the relay board via the factory"pink" ignition switch wire, I've tested this circuit and found I have 12V in crank and run and 0V in off. I just started the car tonight, when I turned the ignition key to off it kept running, I measured my tap into the "pink" ignition switch wire and had 4.5V, so I pulled the main 20A fuse in the relay board to shut the car off. Once the car is off I have 0V with the key off, and 12V with it on! I don't believe there is any leakage through the ignition switch. I also measured the resistance between 12V bat and 12V switched on the relay board, over 1 M ohm.

Does anybody have any ideas? Where is this 4.5V coming from? Thanks in advance for any help provided

If it is the main relay latching on, one possible way is via the ignition (alternator) warning light. To check if it is this, disconnect the warning light circuit at the alternator, or the entire alternator. If that sorts the problem, add a diode to the warning light circuit.

Dave, thanks for the advice! You nailed it. I've already completed the fix, I thought the main relay might be remaining energized, but I didn't have an idea what the source could be.

Many thanks my friend, you made my day!
Dan