Hello everyone,

I’m working on a simple project and would appreciate your help.

I have a 1998 Vortec 4.3L V6 engine with a 4L60 transmission, removed from a Chevy Blazer.
My goal is to run the engine and transmission outside the vehicle (on a stand or test setup), fully independent from the rest of the car systems.

What I need:

I’m trying to understand the minimum wiring, harnesses, and fuses/relays required to run the engine and transmission only — without having to bring over the entire vehicle wiring.

My questions specifically:

• Which harnesses are absolutely necessary?
  Should I just bring the engine harness and ECM? Or are parts of the dash harness also required?
  
• What fuses and relays need to be connected?
  For example: Fuel Pump, Ignition, ECM, etc.?
  
• Which sensors must be connected for the engine to run properly?
  Like: Crank, Cam, TPS, IAC, MAP, O2?
  
• Do I need to bring the original ignition switch (key cylinder) from the Blazer?
  And if there’s a security system (Passlock), how do I bypass it for a standalone setup?
  
• If available, can someone share a wiring diagram or PDF guide that shows how to wire the system just to run standalone?
  

Goal:

Just to run the engine and transmission — no lights, no A/C, no ABS, no accessories.

Any help, wiring diagrams, pictures, or advice would be greatly appreciated.

Thanks

 

Hello, how are you!, greetings from Mexico!, I'm working on something similar in my personal workshop, I changed my old 1983 vortec v6 carbureted for a 1999-2002 vortec v6 removed from a Chevy Silverado 99 2wd with "spider" injection system along with its same 4L60e transmission, if you want to use the same electronic system but only the essentials you will have to simplify the original harness of the donor blazer and its respective ECU to reprogram it, I understand that it is almost the same platform of the LS1 5.3/5.7 LT1 engine series and they use the same reprogrammable ECUs and you can simply connect as you removed The engine with all its sensors and supply its individual currents with fuses and relays I recently got this pinout from an engine that I think is the same, I attach it

That's how far I've come, I haven't reprogrammed my ECU since I have a problem with the exhaust multiples since they collide with the suspension forks of my project and on the engine supports too, when I reprogram my ECU I'll tell the technician to add a signal for the radiator electric fan, a pin has to be added to your ECU connector