1996 Tacoma getting 2002 4Runner Engine

Hi everyone. My 1996 Tacoma SR5 with 5-speed manual transmission has finally bitten the dust. The motor has been drinking coolant for several years and it's time to replace it. It only has 349,905 miles on it! I bought a 2002 4Runner motor with 160k miles that was tied to an automatic transmission. Can anyone advise what challenges lie ahead in this swap, foremostly, will I need to swap wiring harnesses on the engines?

 

If you swap your v6 (5VZ-FE - 3.4l) with a I4 (2RZ-FE - 2.4l or 3RZ-FE - 2.7l), you'll need to change both the wiring and the ECU computer (though the ECU must be for the right engine AND right transmission. So, in your case, manual).

If it's 5vz to 5vz, no need to change the wriring and the ECU (depends on the transmission, as I said)

About the automatic motor bolting directly to the manual motor, I think automatic and manual transmissions connect differently to the motor and you need to swap some stuff as well, but not sure which parts... Others will probably chime in to help you

 

Thanks for replying. Yep, I'm replacing the '96 Tacoma 5VZ-FE with a 2002 4Runner 5VZ-FE. I figured the 02 motor would have a couple extra connections because of the throttle body being drive by wire rather than the old cable. I know I have to remove the flex plate and replace it with a flywheel for the manual tranny. The rear engine mounting plate is the same however from what I've found in my research. If the existing wiring looms won't connect with ease, we'll just swap the harnesses as necessary. Luckily, it appears that the intakes are identical and the big difference between the two is the throttle body and the injector change from 98 to 99. Should be interesting. I will return to post the results after completion so anyone else searching for these answers may find them. The new motor has the oil cooler on the side which I believe my old motor is lacking.

 

I’ve recently been through the almost exact same scenario. My ‘99 had problems with the heads, although it was still running. I had it swapped with a 3.4 from an ‘02 4Runner with about 159k miles on it and so far so good! I did not do the swap myself, I had a local mechanic do it. My truck is auto, so slightly different from yours, but I do know my upper intake (I think) was swapped onto the new motor because of the cable driven vs electronic throttle body. Also, I believe the fly wheel had to be swapped, with a few other things with 4Runner vs Tacoma. However, I do not believe mine had an oil cooler, but I could be wrong. The only issue that has seemed to presented itself within about 700 miles of driving has been the oil pan, it looks like the seal is leaking a little. The bolts seemed a little loose so I snugged them up hoping to solve the problem rather than pull the pan. Also, I don’t believe the new thermostat was installed correctly because according to my ultra gauge, the motor is running about 203 degrees, (installed a OEM 180 thermostat) something I intend to address very soon. Good luck, hope it all goes as planned!!

 

Good to hear it wasn't too bad of a swap. The oil cooler isn't a separate radiator like you'd reckon. It's a small cylinder about a foot away from the oil filter that a coolant line from your water pump runs into. Then it has a small U-shaped return hose that feeds into the block near the cooler. It uses the coolant to regulate the oil temperature. Pretty neat setup. Your thermostat is probably okay. It depends on where you take the reading as to what temp you will see. A 180 thermostat BEGINS to open at 180. The temp at the output of the water pump will be much hotter than the coolant returning after it has run through the radiator. You're probably ok.

 

If it was me unless your into doing the harness splice

Tacoma and 4Runner Harnesses are different enough then add one manual and one Auto without the EWD`sit will drive you crazy

Swapping to drive by wire will take the 2002 engine harness and ECM then you must repin or make an adapter for the 4th ECM plug

Pull your harness all the sensors and throttle body and install on new engine

The Maf`s will also be different pretty simple to use the newer style .

There will always be the little odds and ends

This is just like any other swap just happens to be the same engine

No doubt time for a New Clutch as well

 

I was thinking the same thing - use the old harness and sensors. For the clutch, I've already bought an Exedy 4-piece clutch kit. I'm amazed the first clutch lasted 350,000. It's definitely time to replace that. Thanks.

 

I did the same swap a few years back. I had a 95.5 manual Tacoma and swapped in a 00 auto 4runner. Tranny bolted right up to the new motor just put all your manual transmission stuff on the new motor. I kept the stock harness and ecu. Most of the sensors were the same, I think I only had to swap out a few but it wasn’t bad cause you have all old sensors you can steal. I kept the old air box and throttle body so I didn’t have to mess with the MAF sensor. New motor ended up having a bad injector but that was also a easy fix. I’d keep all the old coils for the spark plugs Incase yours ever go out they are expensive. Same with the power steering pump, alternator, and so on. Always good to have extra parts. My old 3.4 blew a head gasket and cracked a head at 320,000 miles.

 

4runner motor in the Taco with the odometer reading a few months later (it’s in kilometers).

 

Make sure you take care of any seals or gaskets that are hard to reach before dropping the motor in.

 

Thanks buckmaster. You answered my #1 question I was thinking about today which is will the new injectors work with the old harness, sensors, MAF, etc. I read on other sites that the flow rate was the same so I hoped they were compatible.

 

You bet. My parts list is front/rear main seals, front camshaft seals, timing belt and tensioner bearing/pulley, water pump, thermostat and o-ring, flywheel, 4-piece clutch kit and fuel filter. Ancillary parts for reuse with low miles/years from my old engine are starter, alternator, and coil packs (about 6 years old), besides the wiring harness etc. Anything I missed?

 

I put a my 2003 toyota tacoma v6 in my friends 97 4runner. He had to keep his upper intake plenum on the new motor. It was easy.

 

When I did mine I think I replaced the knock sensor also since I was down there. My dad told me to, not sure if it’s needed. He’s a licensed mechanic though haha.

 

It's done! The parts used from the old engine were mounts, upper/lower plenum and air conditioner bracket. The injectors in the 2002 4Runner engine worked fine. It turns out someone had recently replaced the timing belt (looked new) so we left the timing belt and water pump alone. The water pump looked new and had never discharged from the weep hole. Timing belt tensioner/pulley were fine. It did get new front and rear main seals and new camshaft seals however, along with flywheel, clutch disc and cover, and pilot and throwout bearings. I drove it to work yesterday with old engine core in the bed and delivered it back to the junkyard after work. The odometer rolled past 350,000 miles on the way to the junkyard Now I've got some spare parts already listed on ebay. Thanks for the help everyone. It made it a lot easier to plan this out.