Goddamnboh

Hi guys, I have been lurking and reading for a long time about 5vz and 1uz swaps, but just got back into Toyota about 2 months ago. I'm in the process of finishing a 3.4 swap into my 1994 4runner 3.0 Auto, with the donor engine, harness, ecm and accessories coming from a 1996 4runner Auto. So far I've refreshed the new engine, swapped over the necessary parts from the 3.0, built a crossover, and mounted it in my vehicle.

My original plan was to use the a340h with its associated transfer case. However, I'm stuck right now because, from my understanding, I don't have the electronic capability to run this unit with my new 5vz auto harness and ecm. I didn't plan well when preparing for my swap and underestimated how difficult it would be to obtain the t100 parts needed to make this work. I'm looking at all of my options to get this truck up and running as soon as possible.

I've been trying to source a t100 wiring harness and ECM along with the appropriate body harness plugs and evap plug. This is like a needle in a haystack here in Ohio. I've also considered running the a340f from my donor vehicle along with an adapter and gear-driven transfer case, but in all honesty I would like the keep the rest of this process as simple as possible.

Any recommendations on what I need to do to get my truck up and running? Should I keep searching for t100 parts or go with the a340f setup? How much more involved would a manual conversion be? At this point I know I'll be spending more money, but I really just want to get this truck running so I can get the hell out of the Midwest. Any suggestions?

vasinvictor

iTrader: (3)

car-part.com and find a t100 ecu.

69sixpackbee

+1 on what he said! Car-part.com is a great source and you can scroll through and sort by price, location, grade,..etc. I found a T100 ECU for $45.00!

I might not use it but I have it as plan "B" in case my VSS mod I am trying with my A340H does not live up to my expectations. I am initially repinning my plugs for a '98 4Runner ECU-4X4/auto so we'll see how it goes.
You can find all of what you need on that site.

Good luck..Bud

Goddamnboh

Thanks for the replies! I ended up finding a t100 ecm and harness about 2 1/2 hours from me. Picked up the throttle body too. Hoping to add it all to my engine bay over the weekend.

From the looks of things, there is only 1 additional plug from the ecm that will need to be spliced into the body harness of the 94. There was 1 plug for the ecm and 3 additional plugs going to the body on the 96 4Runner harness I was using. Plus the t100 harness mounts on the kick panel too.

I also made sure to grab the connector from the evap canister that is routed to the firewall. Probably should've gotten the entire unit, but I'll see what I can come up with. Looks exact the same as the 94 unit but is located on the drivers side.

I wish I would've found and entire auto t100 and dropped the drivetrain right into my truck. Lesson learned. I'll keep you updated as I begin to start the wiring adapter. Anyone good at deciphering the diagrams?

I

Goddamnboh

So I've run into the problem of getting the t100 harness mated to the a340h. For some reason I thought it was plug and play, I'm not sure where I read that. One more wrench in this process, any suggestions on a quick fix?

Goddamnboh

So I've been working at the wiring for the past few days. I've been using info from another thread to re-pin the C1 and C2 connectors that go to the body harness to match the IE1 and IE2 plugs from my T100 harness. Also splicing and re-pinning E4 from the ecu into the mix.

Most of it seemed to have gone okay, there's a few wires I'm having problems with. Mainly the black and black-orange power wires and 2 that supposedly go to an ABS connector A16.

Plus getting the correct plugs which match the a340h onto the harness has been a pain. I added in the 6-pin blue and white plugs, but there's still some work to do as I have 2 female connectors on the tranny that look to have no match.

Going to try to tackle the vsv setup this week too. Plus I need to add a data connector for OBD2. What a mess.

I don't feel very confident that I'll be able to finish this without some serious help or a lot of luck. I'm starting to look at 3rd gens and an entertaining the idea of a part out if I can't figure this thing out soon.

blake.nemitz

why not just run your low range circuit on a switch instead of swapping ecu's?

Goddamnboh

I think the issue with running a T100 ecu is so the transmission can have the correct shift points. It is my understanding that the L4 solenoid is supposed to be wired to a relay. I need to find a good write up on this and something for wiring vsv into the t100 harness. I've done engine swaps before but this stuff is getting to beyond my level of ability.

Goddamnboh

So I took about a month off and came back to my swap. Was finally able to get it to fire and eventually run after using a Bosch relay in place of the 3.0 COR. Couldn't believe it even ran after all of the setbacks I've encountered along the way!

First issue is the idle is way high, sitting 2000rpm from the initial turn of the key. If I put the car into gear and turn around in the driveway or drive behind the barn it climbs to 3000rpm and holds when put it back on park. Read every thread I can find on 3.4/5VZ high idle, swapped IAC with a spare I had. No change. Unplugging the IAC results in no change as wel!. Pretty sure I'd like to swap throttle bodies and see what happens, but in the meantime I'm waiting for a friend to come by and check for codes. Hoping that can point me in the right direction.

Second issue of concern is that my 4wd is not actuating. Running the stock a340h with T100 harness, computer, and throttle body/TPS. I have an ADD diff and am not sure if the VSV are working or if I got the wiring for it correct. I'm using the documents from kg206's thread since our builds are very similar.

https://www.yotatech.com/forums/f160/3-4-swap-while-keeping-a340h-238665/

Not having 4wd really makes this project meaningless so I'm a bit discouraged at the moment. Part of me wants to drop in a 5 speed, manual hubs and non-ADD diff, and pick up a harness from ORS or ToyOnly, but that's a ton of money. Another piece wants to just sell everything at a loss and pick up something with an extended cab and 22re. But the biggest part wants to sort this truck out and get it to run solid and be reliable. Time is running out though, I'm desperately through with living in Ohio and need to get out of here ASAP. I'm unemployed right now and will need my savings for a fresh start. I've been working on this truck almost everyday and can't seem to move any further forward.

Suggestions, tech support, prayers or ANYTHING would go a long way right now. Please help me finish this swap!!!!

SacRunner

Is your check engine light wired up? It should turn on when you turn the key to "run" but with the engine off, then turn off after the engine starts. Is the light still on after you start it and drive around?

Maybe look for vacuum leaks that could cause the high idle. Use starting fluid to spray around the various hoses and intake, then if the idle goes up, you have a leak there somewhere. Something else to check would be to temporarily disconnect and plug the air lines going into the idle up valve on the power steering pump. You said you've swapped IACs but have you cleaned either of them? Its unlikely that they're both gunked up and "failing" the same way, but it could happen.

As for 4wd, have you put the truck up on jackstands, put it in gear and 4 hi, let it idle then verify that the front drive shaft is spinning? If it is you have a problem with ADD, most likely wiring related, if it's not, you have an issue with your transfer case/shifter.

For ADD debug, did you disconnect the vacuum lines at all while swapping the motor? If you did, there is the possibility that you hooked them up backwards, such that the front end is "activated" during 2wd and then disconnects when you shift to 4wd.

Next check the wiring by looking at the voltage at the VSV plug, the VSV with the brown plug (at least for my 91 4Runner) is for 2wd, and with the transfer case in 2hi, engine running, there should be 12V between the 2 pins, the blue plug should have 0V between the 2 pins. Shift to 4wd and that should swap, the brown plug should drop to 0V between the 2 pins and the blue plug should jump to a 12V difference.

If you're not getting the right voltages at the VSV connectors, you have a wiring issue. Wiring in the ADD correctly was one of the more tricky parts of my swap (97 4Runner M/T into a 91 4Runner M/T). The 97 had a lot of other components in the 4wd circuit than the 91, but I went through the EWD and X-ed out the various components and wires my donor didn't have. Then I re-drew the diagram by hand and only included those components I had, making sure to clearly identify the body-engine harness connectors so I could keep track of what was where. Then it was a matter of trying to "morph" that diagram to work as close to the stock 91 circuit as I could.

Our swaps are very different, but hopefully you can use the generic approaches/techniques to find your last few little hiccups.

dodgefan02

Not sure if you're still needing help with it, but as for the 4wd not working, have you seen the write up on 4x4wire.com? There's a tech article about defeating the ADD system in these trucks. It's not too difficult to do, and eliminates all the vacuum lines & switches, essentially leaving you with a good old fashioned manual 4wd setup.

Goddamnboh

So update to my saga with this 3.4 swap. I was able to get the truck to idle normally and the 4wd to engage. The 4wd was simply my own stupidity, I didn't have any vacuum source going to the vsv's for actuating the 4wd. Simply ran a line to the intake manifold and it shifts in and out like it was designed. Easy fix, just something that can be overlooked for anyone else with a similar problem.

The high idle was in fact two bad idle control valves as SacRunner had mentioned. As he had suggested I did clean both of the valves as I replaced them. Both were carboned up and I used throttle body cleaner on them, but the fix came from when I scraped the gunk off the second valve with a knife blade and made sure to install it with the valve in the closed position. I also put 12v to it directly and sprayed TB cleaner on the valve to clean it while it was moving.

So onto the newest wave of issues, I still can't drive the truck because it overheats. It creeps past 1/2 up to 3/4 on the gauge at idle and will spike into the red when on the road driving. I've swapped fan clutches, thermostats, brand new radiator and Toyota red coolant. Snap-vacuum pump to pull air from the system and have burped the coolant with the front end raised. I tightened my coolant gauge bolts and even swapped the it for another unit. At this point I'm leaning to a backward head gasket install and I'm running low on the time or energy to keep diagnosing or repairing the truck. Not sure what I'm going to do at this point....

So to anyone doing this swap, I would highly encourage you to plan your build in detail before buying a single part. Your best bet is always to buy a donor vehicle. A manual truck would be preferable and I think the consensus for sticking with a 5-speed transmission is spot on. If you have to go with an auto tranny, steer clear of the a340h in favor of the newer a340f. A t100 would be perfect for someone with the need for an auto. Drop the entire drivetrain, harness, and ecm. If you can't do the wiring on this swap, spend the money and outsource it to ORS or ToyOnlySwaps. You'll save a considerable amount of time and headache. And if you aren't a technician or don't have considerable skill in diagnosing and assembling Toyota engines, this type of project may very well be over your head. Find someone with experience who can guide you along the way, there are probably a number members of this forum who would be willing to lend a hand.

And as always rhanks for the help and support YotaTech!!! You guys rock!!!

BTTF

Do you still have the tailgate? I'm interested In the tailgate access panel. How much shipped to 95118?