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Tips For Wiring Your EFI System

Proper wiring is essential to the operation of your aftermarket EFI system.
Proper wiring is essential to the operation of your aftermarket EFI system.
Holley Performance

The key to a successful EFI upgrade starts with making reliable wiring connections with the proper tools, techniques, and crimp terminals. We spoke with Holley's EFI program engineer Doug Flynn, who shared his tips on the basics of making proper wire connections.

1) Never Simply Twist Two Wires Together: Many people make their EFI wiring connections by splicing two wires, twisiting the ends together, and wrapping some electric tape. This only works until something tugs on it and the connection is broken.

2) Use Proper Insulating Crimp Terminals: Crimp terminals provide a positive connection. Use the appropriate terminal for the gauge wire you're using. The color of the crimp terminals indicate the gauge of wire they are made for; Yellow = 12-10 gauge, Blue = 16-14 gauge, and Red = 22-18 gauge wire.

3) Use A Crimp Tool: There are many crimp tools available that are inexpensive. Most will have the gauge color indicators to know which part of the tool to insert the terminal and wire to make the crimp.

4) Never use T-Tab or Scotch Locks: These type of connectors do not guarantee a good connection and can fail at any time.

5) Use Splice Connectors And Solder Wires Together: The best way to connect two wires is to use a splice connector and solder them. This provides the best and most reliable connection. Follow up by covering the connection with heat shrink.

6) Non Insulated Crimp Terminals Are Installed Differently: Non insulated connectors are commonly used for wires like the main power and ground wires for EFI systems. These types of connectors should be crimped from the back side, or the side without the seam or split in the connector. Many crimp tools indicate which bump on the tool is used for non insulated terminals. Once it's crimped, it's best to solder the connection and cover with a shrink wrap.

Most of the trouble-shooting Flynn says he's done on EFI installations are a direct result from poor or loose wiring connections. By making the proper connections during the installation of your EFI system will ensure that it will work properly and without any problems in the future. For more information on Holley EFI systems, visit www.holley.com.

EFI Wiring Tips
EFI Wiring Tips Holley Performance

EFI Wiring Tips

Never Simply Twist Two Wires Together. Many people make their EFI wiring connections by splicing two wires, twisting the ends together, and wrapping some electric tape. This only works until something tugs on it and the connection is broken.Use proper wiring crimp connectors that are available in a set of assorted connectors. 

EFI Wiring Tips: Gauge Connectors
EFI Wiring Tips: Gauge Connectors Holley Performance

EFI Wiring Tips: Gauge Connectors

Use Proper Insulating Crimp Terminals. Crimp terminals provide a positive connection. Use the appropriate terminal for the gauge wire you're using. The color of the crimp terminals indicate the gauge of wire they are made for; Yellow = 12-10 gauge, Blue = 16-14 gauge, and Red = 22-18 gauge wire.

EFI Wiring Tips: Use Proper Crimp Tools
EFI Wiring Tips: Use Proper Crimp Tools Holley Performance

EFI Wiring Tips: Use Proper Crimp Tools

Use A Crimp Tool: There are many crimp tools available that are inexpensive. Most will have the gauge color indicators to know which part of the tool to insert the terminal and wire to make the crimp. It can't get any simpler. 

EFI Wiring Tips: Never Use T-Tab Connectors
EFI Wiring Tips: Never Use T-Tab Connectors Holley Performance

EFI Wiring Tips: Never Use T-Tab Connectors

Never use T-Tab or Scotch-Lock Connectors. According to Doug Flynn at Holley, These will ultimately fail and cause you to have to search each connector to see which one is the problem. 

EFI Wiring Tips: Soldering Makes The Best Connection
EFI Wiring Tips: Soldering Makes The Best Connection Holley Performance

EFI Wiring Tips: Soldering Makes The Best Connection

Soldered Connections Are Best. Soldering two wires together is the best way to make a connection. This provides the best and most reliable connection. Use splice connectors and follow up by covering the connection with heat shrink.

EFI Wiring Tips: Crimp Non Insulated Terminals From The Back
EFI Wiring Tips: Crimp Non Insulated Terminals From The Back Holley Performance

EFI Wiring Tips: Crimp Non Insulated Terminals From The Back

Crimp Non Insulated Terminals From The Rear. Non insulated connectors are commonly used for wires like the main power and ground wires for EFI systems. These types of connectors should be crimped from the back side, or the side without the seam or split in the connector. Many crimp tools indicate which bump on the tool is used for non insulated terminals. Once it's crimped, it's best to solder the connection and cover with a shrink wrap.