Quick Draw

Hello,
I'm a long time lurker of YT, but just joined as I am beginning a 3.4 swap, and I know this is the place to be. Some of you may know me, or my truck "Doris", from TTORA or Marlin. But for those of you who aren't acquainted, here is Doris, my 1980 Pickup, built from stock by me:




Recently, on the way to Holy Cross, I had a major electrical fire. That signaled that its time for a big change. So despite that being a fairly cheap fix, I happened to come across a great deal on a 3.4 and A/T out of a '96 T100. So that's what is going in place of my tired 20R. I have almost everything I need... But of course, I will need some odds and ends, and some advice on those odds and ends.

So I've been searching everywhere, and these are the questions I'm having trouble finding definitive answers to:

1. As far as I can tell, since my transmission is out of a '96 T100, and is marked "3040-LE", it's basically an A340F. Right? Can somebody verify this? If you google "3040-LE" you get virtually nothing...
2. Does this transmission have its own TCU or is it integrated into the ECU? I have lots of conflicting answers on this one. I have a plug on the passenger side of the tranny that isn't connected to anything, and I'm worried that a computer that I don't have is supposed to go there!
3. It would appear the motor mounts are the exact same dimensions between my 20R and this 3.4... I've verified this with a digital mic.. It would seem I could just cut off my current frame mounts and relocate them as necessary. Has anybody ever done this? I'm kind of curious where the stock location would put the motor, but I have serious doubts that its correct.
4. Do I have to get a speed sensor like Marlin sells in place of my mechanical one? I think this transmission has one of its own... And I kind of need to keep that mechanical port for my speedometer. So I don't need one, right?
5. I'm planning to eliminate my Circuit Opening Relay as I have seen some describe here. Good idea? Bad idea?
6. Does anybody have trouble with emissions, with a non-factory, or relocated gas tank? I'm planning to put my '87 EFI tank that I converted to work for a carb back into EFI mode. And its relocated directly behind the cab, above the frame rails.

My plan is to have a body only harness, and make the 3.4 harness pretty much stand alone, except for the necessary input wires to connect the two harnesses. So I've been studying a lot of wiring diagrams including the ones you pay for as most of you suggest, and I *think* I understand how to do this.

In addition, I'm still deciding what do with the gauges and interior. I thought it might be cool to gut my entire dash, then mount a heat/AC box from another truck with ducts, Then build a new metal dash around it with gauges either designed for a 3.4, or completely aftermarket. I only want to do this because the first gen dashes are awful, and it would be so much nicer to start from scratch

Thanks in advance for your thoughts/advice!

thefatkid

You can PM me on COTTORA for a faster response, or start a thread over there.

Quick Draw

Thanks, Brian.

So if I get the VSS from Marlin, then what do I do for a speedometer? I can only assume that I would have to get a new gauge cluster that's not mechanically driven?

Okay fair enough on the COR. The wiring diagram makes it look fairly confusing. But I think I understand a little better how it works.

I actually have Trail Gear motor mounts on my 20R, which rotate. They are a really solid mount, so I get pretty good vibrations out of them, but otherwise they are great. So I could make up for that angle difference with those since they rotate, I think? If not, I'll have no problem fabbing some new frame mounts up.

Obviously, I have a lot of research to do before I can really start. I did start my x-over pipe, and it's coming along nicely. But otherwise, I'm planning to take little bites out of this project between now and January. I laid out a schedule today...so hopefully I can stick to it.

DWEINBERG01

Subscribed. Thinkin about doing the same with me 82 shortbed. Do me a favor... keep extremely detailed notes, so I don't have to work as hard as you do. J/k. Good luck

Ride4Fun

Quick Draw - Yes you can reuse the stock mounts, you will have to cut them out and modify them to sit lower and further back (about 2") to work. I just did this recently on an 85 chassis that I put a 93 4Runnner body on. The transmission crossmember from my 93 bolted straight in and I used it (with the motor and trans. bolted together and sitting in the chassis) to locate the position of the motor mounts. I think that the crossmembers are the same in the 79-85 trucks as they are in the 90-95 4Runners and trucks (I may be wrong on this, but I believe this is true).
As far as the computer - it controls the engine and transmission.
The COR is simple and should be used.
I think that most any Toyota EFI tank and pump should work.

Good luck with your swap, you will love it when you are finished.

NF_Fab

Sweet truck, Cant wait to see it with some horsepower under that hood! The wiring looks complicated on a diagram, but is actually not that bad, let me know if you need some help when you get to that point! come by the shop, or give me a call!

Quick Draw

Thanks, Greg!

SO...I'm not sure how many knew this, but:

I originally thought that I was going to have to get this speed sensor from Marlin for my second speed sensor. Then I was worrying that I was going to have to change my speedometer to electric. However, I saw somewhere about the older trucks having electronic speed sensors in the combination meters to send a signal to the "Emissions Control Computer" So I went out to my truck and started fiddling with my comb meter. I found 2 contacts on the speedometer...and when I hooked a continuity tester to them, I found that it beeped exactly 4 times per rotation.... TA DAH! That's a 4-pulse speed sensor! So all I have to do is send that signal over to the ECU.... and if I'm correct... No other speed sensors needed, right!?!

So I'm slowly finding answers to all of my questions, before just asking all of you... I've already narrowed my "list of uncertainty" tremendously, just by doing some research almost every night.

But here's one that I've been having trouble with:

Does anybody know of a source to get electrical plugs BESIDES a junkyard harness? I need for sure E4...or "A" that plugs into the ECU. Also "IE1" and "IE2" that go between the engine and dash harness. Looking around for a junkyard dash harness, they want like $100...just so I can cut off some plugs. So I'm not too excited about that. I called a couple dealers and got a general "We absolutely DO NOT sell ECU plugs to the public." Great...

NF_Fab

You can order most of them from the dealership, but they are expensive, the problem that I have is that not all of them are still made.. but about 95% of them are. I have a massive listing of the plugs in an identification chart. The other problem I have is that not all of them are listed by year/model. But all of the part numbers are there, and they are typically around 15 a plug..might be worth cutting them off of a junkyard harness, Considering the pins that you need to wire in are also fairly expensive, a few dollars per. PM me, and maybe we can figure out what plugs you need.

Quick Draw

Okay so for future reference, I heard that the Yota Yard here in Denver will cut off plugs for $15 a piece. I called them and got a "Yeah, I guess so...". So I'm going to head down on Friday and give it a shot. From talking to Greg, this is going to be a bit cheaper than ordering individuals plugs and putting in terminals. $15 still seems outrageous, but when you consider that a new plug is $12-15 and the terminals are $2 a piece when I need a few dozen of those, it adds up pretty quick. But if I can't find the junkyard plugs, then it sounds like they are all available through Toyota. Greg was nice enough to look up the part numbers for me which was a big help! Thanks again, Greg!

NF_Fab

Happy to help, keep us updated! especially when you get into the part of the wiring that makes your brain hurt!

Quick Draw

I finished tacking up my DIY exhaust crossover today. I'm going to take advantage of access to a TIG welder at school, so I don't have to arc or oxy/acetylene weld this thing at home. Then I'm hoping to get the 3.4 at least put in the engine bay in the next week or two....whether it sits there permanently or not.

minerdude1

I had to get an extra pigtail for my swap, and I got it from Yota Jims.. I actually think he gave it to me cause I got it off of a vehicle that had an engine fire that messed up the rest of the harness. He will not cut off a plug from a good harness for you though. I was at Western auto parts on Federal and I76 a couple of days ago and they had a T100 out there. Motor and engine harness were gone though. Let me know if you need any help on this since I just finished up my swap.

Quick Draw

Well I got my 20R pulled out on Saturday. It was much easier than I expected. I had already pulled my radiator, drained fluids, and disconnected some things in the engine bay a couple weeks ago. So on Saturday I had to go to do some welding for CSU's FSAE team in the afternoon and didn't have long. Surprisingly only working from 9-noon, I pulled off my transfer cases, unbolted everything, and pulled it out transmission and all.

Today I built a cart to pull around my engines on my mountain property... Heh heh...That kinda failed when I pulled it up the hill over a rut with the ATV... But I can fix it, and fortunately my 3.4 was not on it at the time of the failure! Basically I just need to through bolt my wheels instead of the lag bolts I was using...

Quick Draw

Been meaning to get some pictures for this thread, but it just hasn't happened. I usually get home from school and work until it's dark, and that's just less and less time every day. I'll try and remember to get a shot of my empty engine bay...and hopefully one with the 3.4 sitting in there!

So Yota Yard was worthless for the wiring harness stuff. That yard is so horribly disorganized that just finding the right harness in the first place would be a nightmare. As far as I could tell digging through their crap, it wasn't there anyway. But who knows. I went down the street to Jims and got a few things. But despite him having 10 of the harnesses with the connectors I need, he wouldn't cut a single one... So I'm going to try and deal with that later. The good news is that I was able to barter for a radiator, airbox, a couple connectors and an ignitor to be pretty cheap...$80 in total. But that's the benefit of hoarding Toyota parts that are no good to you.

I've got this weekend slated to have the 3.4 mounted in the engine bay, so hopefully that goes well. I ordered a 23 spline input for my t-cases from Marlin, since they are on sale this week. I also got 4 triple drilled flanges, because they are only $5 a piece right now! When that arrives, then I can hold up the back end with my FROR t-case mount.

dntsdad

Four flanges? I dont think that those will go on the diffs if that is why you got four.

Lysmachia

Subscribed! Great to see you on here Kyle! (And thefatkid too!)

So Rich (TacoToy) is a good resource in CO if you get stuck with wiring questions. I think he helped MrDoug not be so stressed about it. And of course Brian is a guru on it.

But YT has a wealth of 3.4 swap awesomness. Makes me wish I never sold my 3.4... but who knows maybe I'll get another!

Quick Draw

Nah, I just like having extra stuff around. I had it budgeted to get 2 of those at $10 a piece, and when they went to $5 I figured, what the hell... It sounds stupid now, I know...but I often have a large collection of parts, and end up having something that somebody needs, as well as tons of spares for myself. I currently have an entire shed worth of junk. Like I had mentioned with the parts bartering I did at the junkyard, it often works to my advantage. So if I find something cheap/free, I take it whether I really need it right then or not.

minerdude1

What harness parts are you looking for?

Quick Draw

I still need the ECU plug "E4" from a '96 t100.

Here's the pictures I have so far...they're on a cell phone, so sorry for the quality.



I didn't get the 3.4 in like I planned this weekend. I had more to do than I originally anticipated. Hopefully soon....but winter has finally struck here. I had a trace of snow on her last night.

dntsdad

Lol. And I was getting crabby that it was 60 here. Bbrrrrrr!!
What sissys we californians are!!