gerth92

I did a spread sheet to help me understand the wiring needed to do my 3.4 swap. I figured I would post it up after I made sure it worked. It seems to be working fine for me. All the gauges and lights work, plus I haven't thrown any codes yet. This was for my specific situation so hopefully it will help. I had a 94 4Runner with a 3.0 and an auto. I put a MT from a similar year pickup, and the engine was from a 99 4Runner with a MT and 4x4 with Elockers. Also note, I shorted out my neutral safety switch since my 4runner was initially an auto and didn't have the clutch switch and cancel switch. And I shorted out the ADD indicator switch since I have also done a solid axle swap. The Indicator comes on any time I hit the 4x4 positions on my transfer case shifter. Let me know if there are any questions on my spread sheet. Also some pins go to more than one other pin. I just made some 3 or way solder joints when I made my conversion harness.


The big red wire is my external trigger for the starter motor. and the 3 wires with the random plug there are the wires to splice into the Speed Sensor Wires on the 3.0 harness.

gerth92

I found a wiring problem in the conversion harness. PIN 7 on Plug E14 was incorrect. This is the starter output from the 3.4 ECU. In the 3rd gen, this connects to the starter relay and controls when the starter spins. It is not needed. And on top of that, it was making my starter stay on and making it turn on when the ignition was on. I simply went in and cut the wire to fix mine. In the 3.0 the ignition switch ties directly into the starter relay after it goes through the neutral safety switch. Having the 3.4 starter wire connected into the starter relay is redundant, plus you have no control over when the starter relay gets switched on. Which is what happened to me.

coopster

Gerth92, This is quite helpful. Hope OP is still around.

The duplicate starter wire you mentioned cutting in the second post, is the red one on the table shot, right?
That's a succinct summary of what folks are looking for, that photo. It looks a bit shorter than I have imagined. How did you mount your ECM (did you use the MT from the 99's motor?)

Also notable was the Elocker. Did you move the ECU for that, or did you just wire the switch in, no nanny stuff?

To summarize the photo, from the 3 o'clock CCW you have the II3, then the IH1, the OBD2, the E14(?) and then the E12(?), followed by IH2 (at 5 oclock), and the other pigtail (on the 'Q" as it were) is the speed sensor wires?

Your AC and cruise all work good? TIA!!

gerth92

The starter wire I use is the red wire that is coiled up. It has to go from the kick panel to beside the battery on the driver side. I used a connector there and ran the starter wire along the positive battery cable. You could go directly down the side of the passenger fender to the starter just as easily. I just wanted to avoid the hot manifolds.

The red wire I had originally tied to the key and the 3.4 ECU. All you need is the key. So now there is only 1 wire tied to that long red one.

I didnt end up getting the elockerelocker in, I traded this 4runner off for a tacoma so I sold the elocker along with the elocker ECU and push button.

I mounted the 3.4 engine ECU in the same spot as the old 3.0 one. It was tough getting that bundle of wires and plugs inside the kick panel, but it will go.

The AC works perfect. If I recall correctly, all you need is the AC trigger wire for the compressor. There is wire in the 3.0 4runers that originally was for cutting off the AC if the auto transmission was overheating. You have to ground that out. I tied it with my ground wire for the OBD2 plug. You can see it in the picture.

I did not even attempt to make the cruiser control work. My cruise control didnt work to begin with because of the auto to manual swap that I did before the engine swap.