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Alternator and Starter

EFI Wiring Fundamentals

Discussion and questions related to the course EFI Wiring Fundamentals

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Hello, I am currently in the planning stage of wiring up my 1JZ engine and just have two questions regarding the alternator and the starter. The alternator is a 3 wire alternator that has a sense, ign 12v, and warning light. From my research it seems as though I can get away with 20awg wire for all three of these but i've seen different answers. The only value for current draw I could find for this component is that of the ign 12v or the field current wire having a draw of 3-4a in which 20awg would be more than sufficient.

In regards to the starter, I currently have plans to run 3 or 4 18awg pins (my connector only accepts size 20 pins) to a 12awg wire running to the starter as the trigger.

Do these wire sizes look okay? Can I go smaller to a 16awg for the starter trigger?

I have attached my excel spreadsheets in regards to my project.



Attached Files

G'day Austin.

20AWG for your alternator field supply should be fine, its my go-to size for that. You can run 22AWG to the sense pin, as there will be next to no current draw there, so no voltage drop across that wire, so the alternator sees the real battery voltage.

For the starter, the solenopids can draw quite a bit of current. 12AWG is probably a bit of overkill there though, you should be okay with a single 16AWG wire in that situation.

Thanks mate!

Starting physical construction this weekend with that info!!