[Lead foot]

Soon I will installing a '92 TPI (speed density) 4.3 (GMC) turbo engine into a newer '02 TPI (n/a) 4.3 body.

Should I splice the old harness into the newer harness?
Should I piggyback the old ECU onto the new ECU just for the engine management and let the new ECU control the remainder of the functions?

I will be using the old engine harness and have to figure out how to adapt it for the other non engine controls. (Which is the best way?.)

Keep in mind the old ECU was in the pass. side kick panel and the new ECU is in the engine compartment.

What is the cleanest way to merge the old with the new?

Advice, suggestions, warnings?

[1931 steve]

Sure hope your good with electrical diagrams. This is not a job for a beginner. I would suggest that the old harness be used for the old engine. I think you will have trouble getting the 02 ECU to control any thing without all of the inputs working properly. What is the 92 engine out of, and what is it going into?

Steve

[Lead foot]

The old engine is out of a 1993 4.3/auto GMC Typhoon. The "host" truck is a 2002 Chevy Xtreme 4.3/auto.

I have the full harness' from each engine and all the wiring schematics from each, but have to decide the most logical (read: least PITA) way of doing it.

[1931 steve]

The easiest way to get the 92 engine up and running, is to use the wire harness that came with that engine. I can assume that the trans are different the 92 should be a 700 trans and the 02 should be a 4l60 trans which are not the same 4l60 is computer controlled. Also the speedo may not work properly, among other components (if your trying to keep it in stock functioning form). The chances of splicing the old with the new is going to be hard.
Unless you are going to run after market gages and delete such things as cruise control and ABS brakes, I would find another truck body and install the engine into that.

Steve