My 3FE into FJ40 swap (1 Viewer)

[73tlcv8]

Forgot to ask, doesn't the 7 conductor rectangular plug from your cowl harness have the same color wires as the two connectors in your engine harness?

 

[Curtice]

Yes I believe it does. I was hoping to avoid doing anything to the engine harness, so was looking to get the correct 5 pin connector to replace the 7 pin rectangular one (I can figure out the other two wires separately). My 88 engine harness is in great shape and still connected to the engine.

I don't have my schematics in front of me, but I do have all those wires traced and tagged. What you listed sounds pretty good.

I have been using your notes as I try to figure out the wiring. I am getting ready to cut what I need out of the 89 donor harness. I know very little about wiring so will have tons of questions.

 

[73tlcv8]

That is a good plan if your engine harness is in good shape. Mine had a melted O2 sensor wire where it laid up against the exhaust, probably why it ran like crap for the PO and he gave up on it. Most of the injector plugs were broken too. Hope you can find the other half of the round plug, it is not a very common piece. If you have a pick and pull around, check the other Toyota's, you might get lucky, or maybe someone on here has a partial harness.

 

[Curtice]

OK, been hitting the wiring hard the past couple of days. Since I have never done ANY wiring, its taking forever. Spent the time cutting out what I need for the new stuff and detangling.

I am trying to use notes and instructions from other folks. I think I understand most of it, but in the diagram below, I tried to capture the parts of the wiring that I don't quite get or have questions on. Specifically, it is with the ignition wiring, alternator, etc. and how to tie in.

So those who have done this or know what you are doing...how does this look? I am sure I have a bunch of stuff wrong. One of my big fears is that I don't understand some wiring basics and I will wire this to explode . I am using 73tlcv8's suggestion of a new switched relay to the ECU. Anyway, can someone help me out here? How does this look, what is wrong, etc.

Just pretend I am an idiot when explaining to me, and I might understand.

Specific questions I have:
1) For the alternator, should I instead be using the existing alternator wiring? For this, I basically took the alternator wiring from the 62 diagram and plan to recreate it in my 40. Also, the alternator has a YW wire for a "charge fuse"...what is this?
2) The IGN Main Relay has two wires that go to fuses...engine fuse (BL wire) and gauge fuse (Y wire). Can I just tap these into the FJ40 fuses for these purposes?
3) For the new switched power to the ECU, one of the wires went out to a fuse...not sure which fuse and what the purpose is. (this question maybe for 73tlcv8 since I am using his notes).
4) I plan to keep my FJ40 fuse box and add inline fuses where necessary. I count only two of these - an ignition fuse between the relay and ECU and an EFI fuse. Both are on the diagram.
5) Are relays all the same? Meaning, can I take an unused relay from the 62 harness and convert it for my purposes here?
6) I cannot find the alternator fusible link on the 62 harness. Are all fusible links the same?

Thats enough questions for now. Thanks.

 

[Stumpalama]

I see a couple inconsistencies and wires to nowhere. Where does the power to your new relay to the BL wire come from? I'm posting some pictures of my wiring plan based on the FJ62 wiring diagram. Hopefully this can help. Based on the advice of an automotive electrical expert who reviewed my diagrams, I am going to swap out the fusible links for a 30/50A circuit breaker and run 2 10ga wires to feed the RY and big BL wires, unless I figure out that I could power these with a single wire to a fuse/relay panel to power these circuits. I'm just concerned about the electronic noise from the injectors etc. and this may necessitate running individual wires from the batteries.

Overview and written description of the wiring.

A closeup of the ignition wiring:

 

[Curtice]

Thanks! I might be making this too complicated. I'll study yours and see if I understand.

Do you not use the ignition relay?

 

[Stumpalama]

What ignition relay are you talking about? I don't think I have one.

 

[Curtice]

My diagram has one (see below just above the alternator) and I saw from someone elses thread that they were going to use it. If it is not necessary though, I would rather not to keep things simpler.

 

[Curtice]

So your diagram is pretty straightforward, and very helpful. Along with your description, I think I understand much better how to do much of this. I still don't understand the alternator wiring, but will focus on this for now.

 

[Stumpalama]

No, I don't think it is used, since I am using my existing wiring to handle the engine and gauge power. The new relay handles the power to the BL wire that feeds the injectors (big BL), the ECU (thin BL) and the igniter on the coil.

 

[Stumpalama]

As I see it, you can keep your existing alt wiring to simplify the wiring. I wouldn't mess with the alt wiring. You already have all the required ancillary circuits covered with your FJ40 wiring.

 

[Stumpalama]

I'll see if I can find some time to scan in the pages of my notebook. I used 2 wiring diagrams, one being the schematic and the other being the diagram.
I find the diagram easier to digest and visualize since it it laid out logically and spatially versus the schematic which is more technical but helps show the interrelationships of the circuits.

BTW, my 2FE note book is 37 pages of information consolidated from the different threads here on mud and some extra diagrams. Some of it is duplicative, but I figured I'll figure out what parts are unnecessary as I work through the job.

 

[Curtice]

That would be helpful. I have a ton of info printed out too, but not as organized. Thanks for your help.

I am heading out of town for a week, so won't have any time to do this for a while. But want to get this done!

 

[pappy]

My diagram has one (see below just above the alternator) and I saw from someone elses thread that they were going to use it. If it is not necessary though, I would rather not to keep things simpler.

There is no reason NOT to use the main relay. It's part of the harness and makes wiring the engine much easier.

As far as exhaust. I used the down pipes from the FJ62, cut ~12" long. I removed, using a grinder, the OX sensor fittings that are located far down on the exhaust pipes. I then drilled the down pipes where I wanted the OX sensors to be, and welded on the fittings. Of course, that makes the harness that goes to the sensors real long, but that is better than having them too short. The muffler shop then continued the exhaust from there, merging into a "Y." I then ran a 2.5" single exhaust to the back. I did install a CAT, and dang it heats up the floor. You might consider some sort of heat shield.

 

[Stumpalama]

I think there is some confusion regarding the term "main relay". The ignition main relay controls ancillary items and many are all ready taken care of by the stock wiring.
The EFI main and circuit opening relays are integral to the system and are a must.

 

[73tlcv8]

I think there is some confusion regarding the term "main relay". The ignition main relay controls ancillary items and many are all ready taken care of by the stock wiring.
The EFI main and circuit opening relays are integral to the system and are a must.

Right don't confuse the EFI main relay and the IG main relay. You don't need the IG main relay.

Run the circuits separate that are separate in the 62 for the ECU power. The ECU monitors battery voltage for a correction to injector duration, you don't want it seeing a bunch of noise.

 

[Curtice]

Thanks guys. Yes, I do have an efi main relay and plan to install and wire it. My question was I regards to the ignition relay. I will not use it.

 

[Curtice]

Run the circuits separate that are separate in the 62 for the ECU power. The ECU monitors battery voltage for a correction to injector duration, you don't want it seeing a bunch of noise.

Thanks...I think I am starting to see this, based on what you and stumpalama said.

As for the alternator, I don't think I can just use my existing wiring, but hopefully someone can help. The difference is (*I think*) the 3FE alternator has an internal voltage regulator, whereas the 2f engine had an external. I would like to use the 62 harness connection to this - that seems the easiest, but need to figure out how to wire it up.

 

[Stumpalama]

Your alt should be internally regulated since your truck is a 1980.
Either way, I think you can still run the stock salt setup.

 

[Curtice]

Hm. I'll check when I get back home. Its an early 80 (so a 79 for many intents and purposes...changes were made in 8/80). Don't know if that makes a difference. I thought the wiring diagram I have is showing a separately wired regulator, but maybe I am misinterpreting it.