Join Date: Mar 2002
Location: Austin, TX, USA
Re: NO START--horn very weak--even with new battery--Ideas????
I usually like to use the voltage drop method to find out where the juice is going. Use a digital volt meter to read the voltage. First off, during crank, the battery should stay above 8 volts -- preferrably 10 volts.
Then measure between the battery+ post and starter. Should see less than 0.1 volts drop. Then measure between the battery- post and the engine block. Again, should see less than 0.1 volt. Somewhere the voltage is being lost to a high resistance (actually relatively low resistance in a starter circuit). But the end result is that the voltage drop will be hot, and may melt stuff and burn the heck out of your fingers when you touch it.
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI