Zelephant

I will be going to look at a 3RZ donor vehicle in the next few days. The yard is working with me on what I need, but they say pulling the wiring harness is too time consuming for them to do themselves. They say I can come by beforehand, remove the wiring harness myself, and then they will pull the motor.

My question to you guys is: what's the best way to go about doing this? Are there any shortcuts I can take? I don't supposes it's as easy as unplugging it from the ECU and pulling the plug through the firewall, or is it? Should I disconnect everything from the engine, or leave it all hooked up and remove the wires from the cab? If it were you, how would you go about it? I need advice from the wise men of Yotatech!

donomite49

you need the complete engine harness to the ecu, the ecu it self and the body harness
plugs with as much wire as you can get.

i would leave it hooked up on the engine and pull it through the firewall and make sure you get both sides of any connectors that go to anything else you need to hook it up trans etc.

good read here

http://board.marlincrawler.com/index.php?topic=19275.0

Zelephant

Thanks! I've seen the link, the Marlin's website is finicky for me. Lot of info to sift through, too.

I'd like to keep as much of my original body harness as I can and isolate the new wiring to the engine. But I've never done this before, and I don't know how practical that is. With the limited time I'll have at the yard, I don't know how deep I'll get to dig into the dash.

Dumb question, but will the ECU plug even fit through the hole for the wire loom in the firewall?

donomite49

the harness plug should fit through the firewall, my 3.4 did, with the grommet cut off and replaced with the original from the 22re.

what i meant by body harness plugs, is the plugs and pigtails from the donor ecu to the dash harness to create a plug and play adapter to your existing dash harness.

one thing i forgot to mention was the obd diagnostics plug (should be in the console area)which will be on the donor's dash harness.
another thing to remember is to get all the vsv's and or anything else you will need for the swap.
do your research and get everything from the donor at the same time while it is still easily available.

another source would be these guys http://toyonlyswaps.com/
they sell harness' for plug and play.

good luck with the project, i know mine was worth the money and effort lol..

Zelephant

OK, gotcha. Some of the guys on Marlin were saying they swapped the entire Tacoma electrical harness bumper to bumper. That's a little too ambitious for me, the pigtails make sense now.

Where exactly is the OBDII port? I thought it was in the footwell with the ECU.

Interesting link, but can't help me, I'm afraid. They don't do harnesses that involve automatics, and I intend to keep the automatic.

Thanks for your help, I definitely feel more prepared!

donomite49

you can google it for the year of the donor truck.

i thought marlin's thread did the dash harness/guage swap.

you will need to get EWD (electrical wiring diagram) for both vehicles.

http://web.archive.org/web/200807310...ttora.com/fsm/

https://www.yotatech.com/forums/f123...a-fsms-260272/

https://www.yotatech.com/forums/f161...p-info-195670/