1995 4.3L swap to FITECH-equipped 5.7: Need wiring help!

[Jasongriff]

I am looking for information about the wiring harness. Will i need to make changes/replace it. Will I need to do anything with the eprom. I am keeping the manual transmission.

 

[Komet]

Is the ecm in the glovebox or under the hood on your rig? If it's like a '92 you keep most of the stuff from the driver's side because it's gauges and ignition. Most of the passenger side stuff is factory ecm which you won't need, but you will need some of the power that goes in through that bulkhead fitting. You can download the factory service manuals if you search this site for them, that will help you identify what you have under the hood. It's more obvious once you pull the wires out of the loom.

 

[Erik the Awful]

I believe the FiTech has the ECM built into the throttle body housing, just like the Holley Sniper.

Your FiTech has a certain set of wires it will need to run, and then some optional wires. When I put my Sniper in my truck, I cut just a few wires on the stock harness so I could wire in the Sniper's leads. I used the red wire to the fuel injectors to power the Sniper. It's hot whenever the ignition key is on. I'd have to dig into it to figure out what other wires I used.

I took all the spare harness wires and all the spare Sniper wires and zip-tied them out of the way. Some day I intend to go back in and neaten it up.

 

[Jasongriff]

The ecu is behind the glovebox. I want my stock gauges to work. The engine I purchased comes with an MSD ignition also. My goal is to get it to run then remove everything I don't need.

 

[Erik the Awful]

Do you have a wiring diagram for what the FiTech needs? You can get the wiring diagram for your truck here: https://www.gmt400.com/threads/88-98-service-manuals.43575/

 

[Jasongriff]

Erik
My concern come from my ignorance in this.
I think it would have been easier for me to understand a 4.3 tbi to 5.7 tbi or a 5.7 tbi to efi. Both going on at the same time has me hesitant.

 

[Jasongriff]

I can get the efi information. I just want to be able to use as much of my guages as possible.

 

[Erik the Awful]

Ahh, gauges. I didn't have to worry about that on my '89. I don't have any helpful information for you on that front.