Voltage drop question

[AMSOILGUY]

Went to start my car finally after the long winter and I've got a problem. The source in the fuse box that I have powering my ignition is going dead on crank. With the key on it reads 13 volts and goes dead when I turn it over. Now I checked another spot on the fuse box and it drops to about 10 at crank. I know the MSD box needs 9.5 volts at crank not 0. What would cause just this one spot in the fuse box to go dead at crank but not at key on?
Thanks
Jacob

[camcojb]

Went to start my car finally after the long winter and I've got a problem. The source in the fuse box that I have powering my ignition is going dead on crank. With the key on it reads 13 volts and goes dead when I turn it over. Now I checked another spot on the fuse box and it drops to about 10 at crank. I know the MSD box needs 9.5 volts at crank not 0. What would cause just this one spot in the fuse box to go dead at crank but not at key on?
Thanks
Jacob
You need to test voltage at the ignition fuse or any marked "battery". Most accessory fuses don't have voltage when cranking, just at "key on". The only two places that would show voltage when cranking are the battery fuse and the ignition fuse.

[Che70velle]

If all was well with the car when you parked it, I'd suspect you have a battery problem. It sounds like it's puking under load.