So I started this "simple" swap like 5 years ago. It was supposed to be cheap but I like to do things "right" so I ordered a lot of parts from Toyota and bought all new parts where I felt it made more sense. Now it's just an expensive, non-running project that I finally have the time to work on!

Vehicle Basics:
1993 extended cab Pickup V6 5-speed. Has 127k miles, 3" body lift, 33" Super Swampers and the front pinch welds are bashed in to clear them. The truck is very solid - especially for Ohio - which is why I bought it even though it ran horribly. Previous owner had a "family friend" rebuild the 3.0. It literally leaked everything! Gas, oil, coolant, power steering fluid, rear axle lube. Ok, so not brake fluid. I found out that most of the fasteners were barely hand tight so the fuel leak especially was taken care of in short order. The TPS wasn't set correctly and something, somewhere caused the engine to die at random. Left me stranded four times (impounded once) in only three tanks of gas. I wasn't terribly concerned with the engine because...

The Swap:
I had a 351 Windsor that had been in my 1970 Mach 1 that I was going to swap in but I have also owned three V6 Tacomas that I loved and, after research, liked the "stealth" approach to the 5VZ swap (and I was too cheap to buy the conversion bell housing for the Ford). I found a 5VZ locally for sale. It was in a 1998 4Runner automatic that had been rolled - but literally right after the owner had replaced the original engine with a 65k mile donor. It has a new timing belt, water pump, etc. because it was easy to do at the time. I picked it up from the guys who had done the engine replacement and they were very helpful with gathering parts (they have a Toyota salvage yard). The air box was mangled but may be usable. I don't remember if I got all the evap stuff. I got the engine harness and ECU. I tried to grab anything that looked like it belonged with the 5VZ. But not either fuse box apparently.

The first thing once I got it home was that the block didn't have the rear dipstick hole drilled out. I purchased the fixture and drill bit from ORS and all the dipstick parts and oil pickup from Toyota. I swapped my oil pan and reused the old flywheel with a new clutch and bolts. For the exhaust, I got the crossover pipe from ORS, an aftermarket catalytic converter, Toyota O2 sensors, flex tube, and a pile of straight and mandrel bent tubing (the existing exhaust was a rusted pile of hacked together trash). I bought a new battery and a really cool tray - which then needed mounts and paint but looks pretty slick. The old starter was looking ragged so I bought a new Tacoma starter. I decided on an alternator upgrade as well. After three tries I got a setup that worked. There are forum posts about upgrading a 5VZ alternator in a Tacoma and posts about upgrading a 3VZ alternator in a pickup but the big alternator options for a Tacoma doesn't fit a 5VZ in a pickup!!! The frame rails are closer together. Now I can't remember if the one that worked is from an MR2 or a Caddy - but it only needed a shortened adjuster bracket and a shorter belt (went through at least four of those). I swapped in the 5VZ A/C compressor. The engine was installed and all accessories hooked up and adjusted. The exhaust was planned and partially installed except the very front piece to connect the crossover to the cat.

And then there was a short break of several years...

Diving back in I am trying to focus on getting it running just to see if it actually works. This means exhaust and wiring. I was able to find a manual transmission ECU from a 1999 Tacoma. It appears that it connects to the 1998 4Runner harness just fine. I pulled down wiring diagrams from all three vehicles from TIS and am reviewing them now. There's a spot to the right on the ECU for what appears to be an "E5" connector which I don't have. This looks like stuff from the main harness (power, OBD, etc.) that I wouldn't have pulled from the donor (I didn't grab any of the wiring from inside). I did grab a OBD pigtail and plug off eBay to make it work whenever I find the connector. I think I will have a lot of extra wires from the automatic harness (plus a bunch or 4Runner stuff that the Tacoma doesn't have). I'm pretty sure the O2 wiring is bundled with the transmission wires so I have to be careful about aggressively chopping things out.

The reason for this thread (other than as a starter for documenting the swap):
While researching the wiring I became aware that there were some differences in the 5VZ not only regarding the transmission but possibly also between the 4Runner and Tacoma. It sounds like the throttle body may have an extra linkage for the auto trans kickdown? Maybe an extra wire? Is anything else on the intake/throttle body different between those vehicles? I ask because the 3VZ I took out eventually got sealed up correctly and dropped into a 1995 4Runner that I picked up with a blown engine and we had to swap the entire intake because the 4Runner had many more vacuum hoses AND provisions for rear seat heating hoses. Just wondering if I may have a similar issue here? The intake is off the truck right now so if I need to find another now is the time to do it! While searching, should I pick up the Evap parts and/or the the inside fuse box (also some small part to make the A/C work that I read about)?

Thanks,
Troy

I will post pictures up but I have been using Photobucket for 15 years and now I refuse to pay their extortion.

 

Welcome, Troy! It sounds like we're more or less at the same place in our swaps. I can't comment on Tacoma vs. 4Runner throttle bodies. My donor is a 97 Tacoma 4x4 MT, but the throttle body on mine does have provision for an extra linkage for AT use. I'll have the accelerator and cruise control cables connected but the third one will be unused.
As for the O2 sensors, you are correct. They are the 4-pin connectors on the wire running back towards the transmission. I almost made the same mistake with E5 but saw it at the last minute as I was picking up my parts. The good news for you is it's available numerous places and the pins going to the existing ECU will work in the new connector housing. Aside from a few splices and soldered Ys, the pins should be an easy swap with no pin-crimping necessary. Let me know if you need any help deciphering the EWDs. Most people get stuck when they get to the fuel pump relays.

Patrick

 

Thanks!

It seems that if the throttle body *could* work for both that Toyota wouldn't have 2 part numbers - but I know that's not always how it works. If the 4Runner intake has too many ports or outlets I can plug them - as long as I know what I don't need. I bet that's the case rather than not having enough since there's more "stuff" on a 4Runner. The only tricky part would be extra valves or switches and me trying to mate them up with something non-existent.

I don't think I will have cruise but that would be very nice! Once the truck is running I will have to look into it. I'd need the entire setup as my truck didn't originally have it.

That's good news about the E5 connector. I ordered one but didn't get any pins because I figured I would have spares after unhooking some of the functions specific to the auto and/or 4Runner. And they're $5.50 each! For the manual trans there's only 8 wires on that connector but that's still almost $50. It will be awesome if I don't even have to strip any wires!

My biggest issue with the EWDs is because I have 3 years/models to match up instead of the normal 2. Luckily, the 98 4Runner and 1999 Tacoma use all the same ECU plugs and I have only found 1 engine wire that's different (so far). I stripped the coating off the rest of the original 1993 harness last night and laid out all the sub assemblies as best as I could. I'm thinking of doing the same with the new harness too because a lot of it will be unused and I don't want it hanging around. Plus I think I have to add a wire or 2. Reading these diagrams isn't particularly easy so I may very well need help! I also bought an ODB connector and pigtail. It came with instructions as to the purpose of each wire so I just need to figure out where to put them on the harness. Then I can at least use my code reader moving forward. I don't know if I'll be back at it tonight or if it will have to wait for the weekend.

Troy

 

I wouldn't worry about it unless you have EGR (yuck). You really only need three ports: filtered air before the throttle body, an inlet into the intake plenum for EVAP and idle up valves, and a second intake plenum or throttle body connector for vaccum lines.

Unfortunately there will be some stripping and soldering of wires, but it shouldn't be more than 4 or 5. Some wires went through the cowls instead of the engine wire and vice versa, so you'll need to splice a few things.

I also unwrapped my harness so I could get the EVAP, starter, and AC idle-up wires into the bundle. It's surprisingly easy to do so long as you don't rush it. The ODBII wires are all on E5 (SDL, SG, BATT, and chassis ground), so you'll need to find some extra wires with pins that can be spliced into your pigtail. By the way, my EWD calls the ODB connector the DLC3 or D7 connector. Hope that helps!

Patrick

 

It looks like I have 7 wires for the auto trans that I won't need so I can salvage the pins from them. I hope! That's cutting it close...

I'll pull out the intake and get some pictures/count protrusions.

Troy

 

There's a few others you won't need. SEL1 and SEL2 are only used on the 3VZE ECUs, so that's another one or two you can salvage. Your year of 5VZE doesn't use the AC Idle-up valve, so there's two more. In case you haven't already counted them, the two AC pins (ACT and AC1) are not compatible between generations and cannot be connected, so that's two more. If all else fails, my 3.0 experienced rapid, self-disassembly, so I've got some spare 3.0 parts including most of the engine harness.

Patrick

 

I got the E5 plug yesterday. I guess I need to read more about wiring! My 3.0 Harness had 3 plugs to the ECU and 2 pigtails going in to the cab. The 3.4 has 3 plugs to the ECU and 2 pigtails going into the cab but also this E5 that goes on the ECU. I have way more holes than wires! But I now have all the pieces (I think) to start getting it sorted.

Thanks for the help so far! I do want the A/C to work. I wasn't aware that I didn't need the idle up valve so that's one less thing I have to deal with.

Today I'm tackling the headpipe on the exhaust. Lots of welding! But I also got a new starter for the Mach 1 and it's supposed to be mid 80s and sunny soooooo I might not get a lot of "work" accomplished.

Troy

 

96 was the last year that the Tacoma used the idle up valve, although it is erroneously mentioned in the 97 and possibly later FSMs. I'm not sure why Toyota stopped using it, but the signal actually comes from the AC amplifier under the dash, so you can use it if you want to. I wired it up because I had the valve, connector and about 3 feet of wiring, but time will tell if I keep it or not. The only pin you need to make the AC work is the AC Magnetic Clutch pin on IH2 pin 15 (IK1 pin 22 from the 3.4 harness). The magnetic clutch wire comes from the AC amplifier and joins the engine harness via the IH2/IK1 connector.
The 3.0 got away with three ECU plugs by having wires go from the ECU straight back into the IH1 and IH2 connectors to join the wiring in the dash instead of going through the firewall with the engine harness. On the 3.4, these same wires are on E5 which primarily goes into the cabin wiring, while the other three ECU connectors only go into the engine harness. (There's a couple of exceptions to this rule, but they're all splices - the ADD relay, B+, and BATT according to my notes). By the way, don't worry about all the empty holes - I'd say about 30- 50% of the pins from my 3.4 connectors are unused. Some were meant for the AT version, but honestly I think the ECU box size dictated a certain number of connectors and pins but they only needed so many and left the others unconnected. That's electrical engineering for you.

 

So my story is very similar, i bought a 4x4 89 toyota pickup with manual trans a couple years back that had a blown head gasket so i found and bought a 4x4 3.4 v6 out of a 98 4runner to swap in and all the mechanical things are straight forward to me and wont be a problem but of course that leaves the wiring which ive heard can get pretty complicated if i dont buy the $400- $600 wire conversion harness. So i was just wondering how i should get to doing the wire harness without the conversion harness if possible. I have the 98 4runner harness and computer was just wondering how to get about converting all i need so it can work on my 89 pickup. Thanks.

 

Complicated, yes. Impossible, no. Having done it, I wouldn't pay that much for the harness so long as 1) you have the whole harness from the 3.4 with all the connectors and 2) you still have the old 3.0 harness. Everything else is fairly straightforward if you have both EWDs because most functions are the same. Where you might have trouble is the E5 connector (since the 3.0 harness only has 3 ECU connectors) and with the fuel control relay.
The trouble with the fuel control relay is it has two coils, unlike most relays that have one. Either one will active the relay and turn on the fuel pump. One coil is controlled by the starter (so fuel is supplied during starting) and the other coil is controlled by the mechanical vane in the air flow meter so when air is flowing, the pump runs. On the 3.4, there is no mechanical air flow meter, so that signal is provided by the ECU and is turned on when it receives firing pulses from the tachometer. If you don't connect this wire, the engine will start but will die shortly after the starter turns off. I hope this helps, but there's plenty besides myself who can help you if you get stuck.

Patrick

 

There are several good threads here on wiring. You'll see abbreviations like "EWD" (Electrical Wiring Diagram") and TIS ("Toyota Information Systems") which is here: https://www.techinfo.toyota.com/

You can register for an account there and have access to all the Service Manuals and wiring diagrams for $15 for 2 days. They are PDF files so you can download them quickly. Problems is, I'm not sure what all you'll find for 1989. Even my 1993 was a bit "light" on materials. I'm reasonably sure one of the "sticky" threads in this section was for a 1989 so definitely check here for tips. I may have some 1989 manuals in my collection (I had a regular cab 22R, 5-speed for a while).

Once you have the diagrams, you need to map out the functions of the wires from one harness to the other. This is all great for a theoretical exercise but my biggest problem came when I had to actually stare at the harnesses in real life. Not so easy then! It certainly isn't as "clean" as the diagram. The 3.0 harness has a bunch of criss-crossed wires and splices which make it hard to open up and lay out on the ground - but it definitely helps because a lot of the wires regarding similar function are grouped together. The 3.4 has all the engine wiring contained and there isn't a lot that has to be touched. I am normally slow any way but I am glacially slow on this part because I don't want to mess it up. It's not like old car wiring (what I am used to) because you can't just stick a voltmeter/test light on it to see if it's all correct (at least not until the computer is up and processing signals). The bulk of it seems to be making the dash work with the new computer.

I am headed to the garage now to put in some more time on it. Unfortunately, it's 80 degrees and sunny with a nice breeze so I am likely to get sidetracked and spend the day out driving muscle cars...

Troy

 

Another question, will i use my 89 dashboard harness or do i need to use a 98 4runner dashboard harness?

 

I don't recall seeing anyone replacing the dash harness. If you're using the 89 gauges and controls there's no need to change. Most of the conversion wiring process is to mate the new engine wiring to the old dash harness so the gauges work. If you want to use the 98 gauge cluster or entire dash then you'd need the matching wiring - and those plugs will connect directly to the engine harness. But then you've got a bunch of other controls from the 89 to sort out! Essentially, the truck, all its systems, and wiring are staying put. If you drop in a new engine with it's wiring harness you're really only concerned with what it takes to make that work (which is typically just a handful of wires that need rerouted).

Troy

 

Well, big failure! I sat here for 2 days poring over wiring diagrams to mate the 1998 4Runner auto engine wiring to the 1999 Tacoma manual computer. I got my lists all prepared. Most of the pins are the same but the wire colors changed. All good! Then I took a look at the actual wiring and it's nothing like what's on my list!!! I have wires going to pins that are supposed to be empty. The biggest differences appear to be on E7 but there are discrepancies on every connector. I dug out the 4Runner ECU and the part number is 89661-3D320 which is, apparently a 1997 version. Awesome! I removed all this at one time from a rolled vehicle and the guy selling it said it was a 1998 so I never checked. Now I guess I need 1997 wiring diagrams and start all over. In my wire mapping I did manage to document where the wires were supposed to go to so I could probably get it sorted by splitting the harness (like I planned any way). For speed it would be smarter to just repin everything to see if it runs then remove the extra.

Troy

 

You can't really split the harness because there are too many splices between connectors inside the harness. Here's my suggestion for what it's worth: make a spreadsheet and make a row for every pin on your 93, including the empty ones. Write down the wire colors and the name or function of the pin. Then do the same for your 97 harness and match them up, especially on the body connectors that don't touch the ECU. Lastly, look at your 99 ECU pinout and figure out which pins need to be moved on E5-E8. The theory is that the ECU pins involve swapping from the 97 location to the 99 location (since you have a 99 ECU). the body pins go to the 93 locations since you have a 93 body. The only tricky parts then are figuring out which pins aren't used on either your body or your ECU AND also figuring out which wires on your harness need to be spliced together. It sounds worse than it is and having everything laid out in a spreadsheet helps a whole lot. Since my engine is also a 97, I can probably help you out if you get stuck or need to know what a certain pin does.

Patrick

 

For reference... on the EWD it appears the 1997 Automatic 4Runner (possibly Tacoma too) uses the 1998 and later style ECM but the manual transmission ECM has the old style plugs. Which means most of the wiring would be different depending on the transmission! I had read that the 1998 and later were similar so that helped me believe it was a 1998. If I ever need a donor for an auto to manual swap I will definitely pick a 1998 and newer!

What I have done this evening is use Excel to map/compare the ECM plugs and pinouts from the 4Runner wiring harness and the Tacoma ECM (I was already ahead of you!). Obviously the automatic transmission functions aren't necessary and there were two specifically for 2WD vehicles. I was able to match everything else except it appears the Tacoma has an input for "PSW" (Power Steering Pressure Switch) that did not exist in the older harness. After that there are 21 wires on the wrong pins. Hopefully, I can do them one at a time (a few will require double moves) and get through it pretty quickly. I wasn't too sure if I really needed to look at the 3VZ wiring as there really isn't much left! Alternator harness.

I also found the OBD-II connector pinouts so I can get that working as well.

I haven't dug into the body/dash wiring connectors yet. I don't have a 1993 Pickup EWD and the only one available on TIS is for 4Runner (which I did download since I assume most of the body wiring may be the same). I do have a big PDF that identifies Toyota wiring connectors (how I got the part number for E5) but the large gray connector behind the kick panel doesn't seem to exist. I don't know how these connectors are identified in the EWDs. I basically know there are two connectors that enter the truck alongside the new (and old) engine/ECM harness and there are two connectors mounted behind the kick panel near the ECM. I assume the functions are similar between old and new. My plan was to use the old connectors from the 1993 harness with the pins from the new one. I will dig around the EWDs that I have to see if I can find these but if someone can point me to the right section I would greatly appreciate it!

Troy

 

Automatic and manual ECMs have been different going way, way back. In 97, 96, and 95, the automatic ECM uses 4-row connectors and in some cases more connectors, while the manual ECMs use 2-row connectors (either 3 or 4 connectors depending on generation). The two big body connectors behind the kick panel are either IK1 and 2 or IH1 and 2 depending on the generation, but they have most of the same features and the pins are physically compatible once moved to the correct location on the second gen connector housing.
One big difference between generations is the third generation Tacos and runners have an extra ECM connector that does not go into the engine compartment (it goes to the cruise control, instrument cluster, etc), while second generation vehicles only have three ECU connectors (M/T) where some of the pins go to the engine harness and some make a U-turn and go to the body connectors (IH1 and IH2).
I found the overall EWDs to be the most helpful in tracing out functions because otherwise you have to search each individual section for pins on the IK1/IH1 and IK2/IH2 connectors as well as the ECU pins, which frankly is a pain. The overall diagrams will tell you which pins you need to trace and which sections to go to. Incidentally, I don't see a PSW pin on my 97 and earlier EWDs, so it's probably a monitoring pin for the newer ECUs so they can throw even more trouble codes.
If you have some specific questions about the pin outs, let me know and I'll do my best to answer them with the EWDs I have. Of course it's all academic until I start the engine this weekend and find out what codes I have.

 

Ok, I am now a master at unpinning wires (pinning them back is kinda easy). I only touched the ECM plugs. One wire went to the new E5 so it looks like the rest for that plug are either from the body plugs or spliced off of another ECM plug. I did find the 4WD wire on the 1997 Harness goes to E5 so I don't have the wire. On the 1999 ECM it goes to the big plug so I pulled the original out of the 3VZ harness. The STA wire is similar in that it does exist but I need to verify the connector is the same. The 1997 harness has a wire for a ground near the cam sensor (G-) but the 1999 harness just splices this to NE-.

I made a spreadsheet with the to/from wiring of the IH1 and IH2 plugs in the kick panel. I also marked the current pins and wire colors to validate the diagram I have is correct. The good news is that all the wires for functions related to the Auto Trans, ABS, and Cruise are missing (I don't have any of those on my truck). The bad news is that I have 2 wires that are in pins that my diagrams says are unused. Bummer! On IH1 I have a white/green stripe wire in Pin 12. On IH2 I have a green/red stripe wire in Pin 10. All the rest appear to match.

The next step is to find the corresponding wires coming in from II1 and II3 on the 1997 wiring harness. The IH1 and IH2 connectors seem to have multiple wire gauges and pin sizes while the 1997 wires are uniform. Hopefully this doesn't become a big problem when I try to reuse the male connectors from the 1993 harness.

Troy

 

Are you sure you don't mean IK1 and IK2? On my EWD, I have pin 10 on IK2 as a G-R pin labelled ELS going from the fuse box to the AT ECU. I assume it is a power pin for something controlled by the ECU. The only thing I can find on my diagram with a W-G pin is the EVAP VSV, but it's on pin 26 of IK1. The EWDs have been known to have bad info in them, so it's possible the pin number is wrong in mine or in yours.
Regarding E5, you are correct. Most of the pins go to IK1 and IK2. If memory serves, STA goes to the ECU but also has to be wired to the starter trigger. In the second gen vehicles, the starter trigger is part of the engine wire, while on the 3rd gen it is part of the cowl wire - hence the missing trigger wire going to the starter. You have to add it to your engine wire to bridge the gap between gens.

Patrick

 

These are the existing plugs on the 1993 wiring at the kick panel. They're IH1 and IH2 for that year as far as I know. For clarity, IH1 is the gray 24 pin connector numbered 10880 and IH2 is the white 20 pin connector numbered 10810. My truck has a manual transmission so I wouldn't have any wires that were A/T specific. On the 1997 4Runner wiring diagram, the IK1 connector mostly contains Power Antenna, Window, Mirror, and Door Lock wiring. I don't see any reference to IK2 at all. The kick panel plugs coming in with the engine wiring are called II1 for the gray 10 pin connector numbered 11537 and II3 for the white 26 pin connector numbered 11611. These are the diagrams I have pulled down from TIS within the last month. Just for fun... the 1999 Tacoma EWD doesn't have an IK1 or II3 but II1 is for taillights and IK2 looks like the main connector as it has power wires for starting, injectors, etc. Not confusing at all Toyota...

Having said all that... I also found a Black wire in pin 5 of the 10 pin connector from the 1997 that doesn't appear in the EWD. The wire in pin 6 does appear to be black as well but the diagram says B-Y. All the other wires on both plugs can be accounted for. Most of them aren't needed for my truck as they are ABS, ADD, Cruise, and A/T specific. For instance, the 10 pin connector has 9 wires: STA and W in 1 and 2 but the rest are Cruise and ABS (except for 5 which is unknown). On the larger connector, all but 1 of the first 14 pins are for the A/T, ADD, SRS, or are 3RZ specific.

Now I just need to sort out which wires from the 1997 plugs go to the existing 1993 plugs in the kick panel. I only have 14 coming in but it looks like about 29 being used by the existing plugs.

Does the A/C Amplifier from the 1993 work with the wiring from the 1997? From reading threads here I thought the amplifier was a later model thing but it appears I have one. I was bummed that I forgot to grab the one from the donor.

Troy