HEI install - help with 12v power please!

[Broncobowsher]

O.K. Had a chance to check voltage at various spots & this is what I came up with. The battery reads 12.5. Drops to 10.6 during cranking. These are the same readings I get from the stud on the back of my ignition switch (the acc stud I believe it's called). I get slightly lower readings on the I terminal of the solenoid. So wouldn't the ignition stud work the best for the single wire going to the HEI? That's how I have it wired now but its been difficult starting. However, since reducing my timing from 12 to 8 degrees yesterday, it's starting better.

The I post will read the same as the ignition switch and battery (minus some minimal connetion losses) IF there is no load. If you are measuring the wire without a load on it you cannot tell if there is still a ballast resistor in it or not. It takes a load for the ballast resistor to drop voltage.

Those battery voltages look slightly low. May want to have the battery and charging system checked out.

 

[YNOTBOB2007]

What I don't understand is how can I get any more voltage than I have now coming from the stud terminal, as that is giving me the same voltage during cranking that I get directly from the battery during cranking. What am I missing here? If the stud terminal is only hot in ACC and RUN, how come I'm getting 10.6 volts during Start? Not trying to be difficult, just want to understand before I add more splices into factory wiring.

 

[Viperwolf1]

What I don't understand is how can I get any more voltage than I have now coming from the stud terminal, as that is giving me the same voltage during cranking that I get directly from the battery during cranking. What am I missing here? If the stud terminal is only hot in ACC and RUN, how come I'm getting 10.6 volts during Start? Not trying to be difficult, just want to understand before I add more splices into factory wiring.

You can't get any more voltage than the battery is willing to provide. And if there's enough bottleneck wiring along the way the voltage will drop significantly when you put a load on it.

I can't say why your ACC terminal is hot in START but it shouldn't be. I can think of some creative wiring to make it that way but why would anyone do that? The idea is to kill the ACC load to help during cranking. That's why wipers and heater blower shutoff when cranking.

 

[YNOTBOB2007]

Thanks. I'll just be sure I keep all ACC items off during cranking since it seems my switch has been altered. I really didn't want to splice a wire back there if I could find a workaround.

 

[YNOTBOB2007]

The I post will read the same as the ignition switch and battery (minus some minimal connetion losses) IF there is no load. If you are measuring the wire without a load on it you cannot tell if there is still a ballast resistor in it or not. It takes a load for the ballast resistor to drop voltage.

Those battery voltages look slightly low. May want to have the battery and charging system checked out.

Thanks Broncobowsher. I just talked with the DUI folks & they test their distributors at 11 volts during starting. I'm at 10.6 during starting, then 12.5 during run. My battery reads 12.5 (before starting). Is it normal for a battery to drop almost 2 volts during cranking? I have no accessories on during starting. Sometimes it fires right up, other times it takes lots of cranking.