3VZ swap in '88 Gen1

I just purchased an '88 Gen1 that already has a 3.0 3VZ engine installed in it from a '95. The PO said it never ran well after the swap due to electrical problems so he messed with the engine harness and now it's looks like spaghetti under the hood. I did notice that the engine harness and ECU are still the original ('88). I am planning to replace the engine harness and ECU with ones from a '95 but wanted to know if I can reuse the original '88 main cabin harness. Any help or guidance would be greatly appreciated. Thanks.

 

The engine harness is going to have a different end on one or more plugs that connect to the cab harness. The 95 harness will have an electronic speed sensor and the 88 should have the manual cable. I did this before. I depined the plug end and swapped plug ends to the 88. Not all the wires will match up color wise and amount of wires.

 

Thanks. It's a manual trans so I don't think I have to worry about the speed sensor. Any chance you have a diagram or schematic showing the pin layout of the 1995 engine harness connectors and the 1988 cab harness connectors? Some of them look straight forward based on color and wire gauge but not all.

 

The one I did was manual also. The 95 has a speed sensor located in the transfer case. The 88 will have a manual cable that attaches in the same location. The new 95 engine wire harness will have wires to operate the speed sensor. And yes you will not have to worry about it. The wires will not go anywhere. I have a wiring diagram manual for an 89 tr4, but I do not have anything for the 95.

 

Thanks for the info. I have the pin layout for both the '88 and '95 ECUs. I'm going to check continuity between the pins of each connector and the ECU so I can identify each pin at the cab harness connector interface. I'll do that on both harnesses and then I can decipher which pins need to be moved over. I'll start a new thread if I get it running.