I'm trying to hunt down why my Holley ECM keeps instantly shutting off randomly. I have been playing with the key switch and notice an unfamiliar noise when moving the key switch.

With the key switch in the ON position, if I rock the key switch (within its normal slop) toward the crank position then I will hear a single click/pop noise from under the dash. This happens just before feeling spring tension of the CRANK position. The noise sounds electronic, sort of like a radio static pop. Rock the key a bit back and the pop happens again.

Any ideas what it could be? This may have nothing to do with the ECM problem but now I'm curious.

I think the noise normally is masked by the noise of the tumbler and starter cranking. But now I'm noticing the noise since I'm stopping short of cranking.

 

I put a new(rebuilt) steering column in my car last year. All the switches /bearings and lock cyl were new. It's amazing how much smoother everything was. The accessory/on and start positions were much tighter than the old column. So it could be the actual switch that the lock cyl inserts into.

also, my pro flow that I installed new in 2019 started doing some weird stuff in 2023. It wouldn't cycle on every so often. After a bunch of ground checks and the usual connections looked at, it turned out to be something crazy simple, the main relay. I replaced it w a high quality relay and it's been good since. After that, I replaced all the relays in the efi sys w better relays.