It depends on the model year of the 3RZ donor. If it is a dizzy motor, I believe you should be able to get by on your original harness and electronics. If it is not a dizzy motor.. ie coil packs / COP, you would either have to swap cylinder heads, or figure out how convert/swap your electrical harness.
You will also need to use your original oil sump and pick-up tube and flywheel
I have a ‘96 Tacoma, 4wd, manual transmission with a 2rz. All of a sudden truck wouldn’t start. Troubleshot and found no spark. Bought a new distributor from local Napa. When the truck turns on it’s got a really rough idle and won’t stay on unless I hold the accelerator pedal. Return this one thinking it’s faulty and get another, same symptoms. Ordered one from Rockauto and still displaying same symptoms. Here’s the kicker I put the distributor from Rock Auto in my buddy’s 3rz and it worked fine.Put his in my truck and works fine also. What am I missing here? Why doesn’t it work on my taco but works on another? Pls help!!!
With my buddys distributor the truck runs fine and his truck runs fine with the new one. I tried putting the new one back into my taco and still getting the rough idle and wont stay running without holding accelerator pedal. Initially when I scanned it, forgot the code but it gave me “faulty camshaft position sensor”. Tried to find the location online and it pointed me to the distributor since it’s got one. The ones with coil packs have the camshaft sensor on the head next to the intake. This is the reason why I replaced the distributor.
Here (attached) is the 1995.5 / 1996 2RZ / 3RZ distributor section from the FSM.
Certain alignments must be verified in both removing and installing the distributor. It might explain everything if you hadn't gotten the alignments right when removing / installing your distributors on your truck, but they happened to be right when installing the distributors during the swap-out with your buddy's truck.
If the gear (whatever) is misaligned it might explain why the ECM is confused about camshaft / crankshaft angles and / or timing and is causing the rough idling.
It might well explain the PO340 code which (I suspect is the one ... ) you're getting. The PO340 code is thrown when the ECM isn't getting the expected signal from the camshaft position sensor. I'm not 100% sure, but I suspect a signal arriving at the wrong time has the same effect as a signal that's MIA.
The code might point to a wiring / bad connection problem, except ... I don't see how your buddy's distributor could have worked fine in your truck if your truck's wiring was bad.
My suggestion is to remove and re-install the distributor following the detailed instructions in the FSM section I've posted here. Double-check everything and report back whether it made a difference.