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fuel injectors fuse size

EFI Wiring Fundamentals

Relevant Module: EFI Wiring Harness Design > Power Supply > Sizing the Fuses

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Discussion and questions related to the course Motorsport Wiring Fundamentals

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Hello,

In the example given, 4 injectors drawing 2A would end up being protected by a 15A fuse.

Only in older type of EFI are all injectors firing at the same time. I witnessed starting from the eighties (LE-Jetronic, Motronic, Ford EEC IV etc) the injectors are fired in batches of 2. so the wiring will only have 2x2A (in the case of a 4cyl). With a 150% margin for selecting the fuse, it will give us 6A, so a fuse of 7.5A will do.

This is how I would approach the sizing. Any feedback from others on this one?

Do it. If you have a problem, you can always use a larger fuse.

The goal of the fuse is to protect the wire, and normally the wiring for injectors can handle 15 amps.

Thanks. I prefer to blow a fuse at the early stage than letting too much amps damaging components too badly.

If a fuse blows, the component is already damaged, because it's the component causing the excessive current draw, assuming that the fuse blowing isn't because of a damaged wire, or wires.

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