MSefi.com read only forum (Jan.15,2018)

I need to start building my injector harness and also need some misc wire for my homemade relay board and other stuff. Correct me if I'm wrong but the injectors should be 14G wire? I was then planning to use 18G for my relay trigger grounds (pin 85 on the main) and 18G for the wire from my ignition switch to pin 36 on the main.

I would also like to use GXL wire. Does anyone know of a good online supplier?

14 gauge is way overkill for injectors. If you run high impedance injectors, 20 gauge is fine, low impedance you can run 18 gauge. Don't forget that the DB-37 pins on MS can only support 5 amps each, no reason to go with huge wire when the connector limits your current capacity.

I run the entire power circuit for my EFI systems using a 14 gauge wire, including the fuel pump. Power for the entire harness (all injectors, coils, MS, wideband, etc) runs through a 16 gauge wire.

www.waytekwire.com has GXL and TXL wire, as well as a lot of generic wiring supplies. www.bmotorsports.com has a lot of OEM connectors and terminals. If you start using OEM style open barrel terminals, do yourself a huge favor and get a proper crimper.

I have the DIY harness. I found in another thread that they use 14 gauge for the two injector wires. Each wire splits and goes into two pins to support additional amperage.

I bought some 14 gauge and 18 gauge to finish my wiring. It just arived today. Mainly I needed the 14G from the main relay to the injectors and some smaller ground wire for all the sensor grounds. I plan to run an 18G red wire from my ignition switch to the relay panel.

Thanks for the supplier. I'll keep them in mind for the next wire order. I do have a good racheting crimper with three die sets for various connector styles.

I'm resurrecting this old thread, because it already answers most of the questions I have on this subject.

As said above, the pins in the connector can only handle 5 amps. The 20 gauge wires come out of the pins, join together into a 14 gauge wire. That wire runs thrugh the engine harness to the injecters. It is then split back out to 20 gauge wires to feed the individual injecters.

I'm using high impedance injecters. Can I connect each of the four pins to a 16 or 18 gauge wire, run all four wires through the engine harness, and then split them at the injector? Each pin would have one wire straight through, and then feed two injectors.

I know that would make the harness a little bigger. But that would eliminate some splicing and connecting.

Anybody see any problems with that?

That would work fine.

But do make sure the injector plug terminals can take the two wires you need. In the UK, the wire sizes are metric, and not available in the same ranges as AWG types. But in any case, it's very much easier to make a joint within a loom (when making it up), as solder connection is fine there as it doesn't get subjected to the same flexing as at a connector.