voltage drop in system to 9 volts when cranking

how do i fix this, there are 2 battery's in trunk series together motor cranks good but drops to 9 volts and digital 7 will not fire while cranking it will pass the scratch test .... Help

What size are your battery cables?

how do i fix this, there are 2 battery's in trunk series together motor cranks good but drops to 9 volts and digital 7 will not fire while cranking it will pass the scratch test .... Help

This may be a dumb question, but you DO have the ignition wired to receive voltage with the key in the start position, right? Sorry if that's too basic, just getting a starting point.

Greg

Had this problem with my 460 powered 71 Maverick. I eliminated the "Ford type" starter solenoid. Bought 00 welding cable, and used it to wire the battery to the starter stud. Then I took the original wire and ran a ground from the battery to one of the starter mounting bolts. Removed about an inch of insulation where the rear spring perch was, and made a lug out of 3/4" copper pipe, soldered it on and bolted it to the body, then did it again at one of the transmission crossmember mounting bolts. Probably an overkill but it fixed it.

Mine would go down to six volts and had loss thru the power and ground circuits.

BTW: I made all the lugs out of copper pipe. Hammered it flat and soldered every connection.

Al

Thanks for the reply