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Thread: early (1991-93) vs. later (1994-95) JDM engines

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    early (1991-93) vs. later (1994-95) JDM engines

    what are the differences between the 91-93 and 94-95 2TZ-FE engines?

    i'm going to buy a JDM engine for my 1991 previa and there is a naturally aspirated version available, listed as a 1994-95 2TZ-FE (not FZE). how is that different from the earlier years? will there be difficulty or extra labor in the swap? will we have to strip down all the peripheral components, like the intake manifold and EGR?

    what exactly changed?

    thanks for your help, i really want to get my van back!

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    Re: early (1991-93) vs. later (1994-95) JDM engines

    i bought the engine today and i'll try to post up when the job is finished, to let you guys know how compatible things ended up being. i'm sure the long block will be fine, but the peripherals might need some swapping.

    i gather that the only difference with the engine itself is the crank position sensor that seems to have been added after 12/1993, which can just be left unused on an older van. i'm not certain though, but i got a good deal and the worst possibility here is having some extra labor.

    i don't have a garage so i'm letting a mechanic do the work, but i'll post up how things turn out.

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    Re: early (1991-93) vs. later (1994-95) JDM engines

    oh wow.

    Who is this mechanic that has agreed to do this?

    Sounds like a chore but hope it works out
    I was a member for 2 years before I bought my van.
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    Re: early (1991-93) vs. later (1994-95) JDM engines

    Quote Originally Posted by Andywear View Post
    oh wow.

    Who is this mechanic that has agreed to do this?

    Sounds like a chore but hope it works out
    The one getting paid for it
    -Russell
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    Re: early (1991-93) vs. later (1994-95) JDM engines

    man i would really love it if someone knew the details about this.

    so the situation is getting all dramatic because the engine arrived at the shop, with a tag on it that said "2TZ-FZE". i had the importer look into it, and they told me today (1) no, it's an FE like you ordered, (2) it's horrible swapping a 94+ JDM FE into a 91 USDM previa due to multiple part changes, and (3) multiple customers have swapped FZE motors (without the supercharger, i assume) into NA previas without issue.

    i really, really wish i had a garage.

    anyway, is this going to suck? should i return the whole thing and try to find a 91-93 engine? what are the details? naturally, this doesn't seem to be as well documented and easy to search out as with enthusiast cars like SR20 nissans, etc.

    it's not easy being weird and egg-shaped

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    Re: early (1991-93) vs. later (1994-95) JDM engines

    [Begin Disclaimer]OK, it's take-it-with-a-grain-of salt time, since what follows are extracts from years-ago Yahoo Previa Group discussions that I remembered seeing. I have all the messages from the group, but they're blended in a mish-mash of control sequences and text, so I did my best to pull out the relevant discussions and hand-edit out the crap. Also, I've never done the swap, just read about it. [End disclaimer]

    But first some finds from this site and the interwebs that may be useful. The implication is that the na version probably didn't change and you don't want to substitute a turbocharged version.

    https://www.toyotavantech.com/forum/...d-non-SC-motor
    https://www.toyotavantech.com/forum/...spotting-guide
    https://en.wikipedia.org/wiki/List_of_Toyota_engines

    Here are a couple of messages (in order, top to bottom) from the YG, circa 2009, between Eric Collins and George Kokolakis, two very knowledgeable gents. In the first, Eric makes a "comprehensive" list of stuff to refresh his van along with the JDM swap. George points out an issue with an incompatible knock sensor on the JDM, etc.. A fourth message is Eric in a later discussion pointing out what he considered to be just the essential things to be done in a JDM swap. Note the comments that a lot of the sensors can be busted on a JDM engine.

    I can testify to the fact that it is an immense PITA to do a lot of this stuff with the engine in place (dropped slightly with the motor mounts removed)

    [Eric C, Yahoo Previa Group]
    I'm trying to put together a list of parts to order that I'd like to replace while doing my upcoming JDM engine swap-out. Here's what I've got so far.

    Recently replaced, plan to re-use:

    • Dist. cap and rotor
    • EGR valve, modulator, and BVSV
    • Oil filter/ toyota red coolant
    • spark plug wires (OEM)
    • PCV valve/grommet (grommet pn 90480-18001 is no longer available from 1sttoyota, anyone know a substitute or should I try to re-use an old grommet? the one in my dead engine is only about 10k miles old)
    • Water pump o-rings
    • Oil filter bracket figure-8 o-ring (must be removed to replace water pump)
    • Thermostat and o-ring
    • All 4 Engine mounts
    • SADS support bracket mounts, Front R & L, and Rear
    • SADS bushing repair kit, probably from ABC Mart on ebay
    • All water by-pass hoses that I didn't replace last time with the 4 main radiator hoses
    • All fuel hoses (within reason)
    • All vacuum hoses (within reason)
    • Exhaust gaskets (The FSM indicates that removal of the entire front exhaust is necessary to remove the engine, meaning disconnected from the engine manifold AND the rear exhaust/muffler section.; I was hoping to leave it in place and just disconnect it from the manifold and then install the new engine with the 2 gaskets/o-rings. Will it be too hard to clear the exhaust if its still hanging there when removing/installing the engines?
    • Anything else I'm forgetting for an engine swap-out? Any other gaskets, seals, etc?


    I'm considering but not sure if worth it:


    • Fan Clutch? AFAIK its original and with 315k it might be smart to replace? Worth it to replace with OEM for $127?
    • Radiator? I know its original, and although I've never had a cooling problem, should I consider getting it rodded out or just replace it entirely as a preventative measure? The OEM radiator is over $300 so that's expensive, but I worry about aftermarket quality.
    • Also considering replacing the front struts, sway bar bushings, and link kits while the engine is out b/c they are also worn originals, but not sure if I want to go with OEM or aftermarket for these parts.
    • What was the consensus on the struts? KYB Front struts and strut boots but OEM strut mounts and rubber isolators?


    [George K, Yahoo Previa Group]
    Have you confirmed what comes with the engine? Usually, you would think that it would come with the water pump, dist cap and rotor, fuel pressure regulator. A tune-up and oil change are usually a good rule of thumb when dropping in a motor. Take a look at the sensor located at the top of the motor. It should be close to the ground point where 6 or 7 straps are bolted to the top of the motor. They’re all located in the valley of the motor between the head and body. I think this is the knock sensor and it might be different between the 2 engines. Also, while you’re there, make sure that the ground point is clear of rust and that the wires are solid before you bolt them in place. When you see it you’ll know what I mean.

    [Eric]
    If I find that the knock sensors are in fact different, which one should I use? Will the JDM knock sensor not cooperate with my ECU?

    [George]
    When I installed my replacement motor and we were in the process of connecting everything (luckily the engine wasn't fully bolted in place) the problem with the knock sensor came very apparent as it had a totally different connection and would not work with my van. I just swapped it with\nmy old sensor and everything worked fine. Actually, within a few miles (well, maybe a few hundred) the fuel pressure regulator went as well and luckily, since I still had the old motor, I was able to swap in the regulator from my old motor. Saved me about $150 buying a new one.

    [Eric, years later, on another JDM discussion]
    That list I put together a few years ago was probably a little overly comprehensive for most. Both the vans Ive done a JDM engine swap on I did all the work myself, so I could afford to splurge a bit on the replacement parts. Both were also 91s and 18-20 years old and hadn;t really seen any preventative maintenance during that time, so a lot of the parts I replaced were the factory originals. I basically went into the projects with the intention of refurbishing themhopefully getanother 20 years of reliable and trouble-free service.Anyway,more reasonable list that I would recommend for most swaps would include the water pump and thermostat, full tune-up (plugs, wires, cap, and rotor), possibly the valve cover gasket and distributor o-ring if you suspect oil leakage could be an issue, and a full clean-out of the EGR system/intake manifold. Both JDM engines I bought had quite a bit of carbon build-up in the throttle body, EGR valve, and blockage in the passageway between the EGR valve and the intake manifold. It's much easier to clean these parts before you install the engine, and highly recommended so you can start out with a fresh and clean air intake/EGR system.

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    Re: early (1991-93) vs. later (1994-95) JDM engines

    wow thank you for going to the trouble of digging up all that information. super cool. i have an update, the importer really doesn't know whether or not i got an FZE because they ship them out interchangeably with the 1994+ FE.

    i still don't think the information i've read is definitive, but my best guess is that a 94+ engine will not be much more labor to install in my 91 than a 91-93 engine would, assuming i've gotten an NA engine.

    so the question is whether or not a 2TZ-FZE (minus the supercharger) would swap in and run interchangeably with an FE; whether the slightly lower compression ratio would be significant to performance; whether the FZE uses different injectors, MAF, and other engine management than the FE; whether or not this is going to run smoothly, installed into a 91 with 91 engine management; and so on.

    i am finding a lot of answers in this document, called "NEW FEATURES" (of the 2TZ-FZE):

    The intake manifold of the 2TZFZE engine is basically the same as that of the 2TZFE engine.
    However, the path of the EGR gas has been partially changed in accordance with the changes in the EGR system.
    The ignition system of the 2TZFZE engine is basically the same as that of the 2TZFE engine.
    However, the G pickup coil is built into the distributor, and produces the crankshaft angle signal [G signal]. The
    crankshaft position sensor is mounted on the timing chain case, and produces the engine speed and the crankshaft angle signals [NE signal].
    The engine control system of the 2TZFZE engine is basically the same as that of the 2TZFE engine. However, the 2TZFZE engine uses the 2group type MFI*1 [EFI], in which the ECM*2 [engine ECU] controls the supercharger system, and uses a diagnosis system which conforms to OBDII.
    so i gather the FZE uses the same ECU, presumably the same injectors, and a slightly different intake manifold. but again it's better to get the word of someone who's actually done this. the importer says their customers have done it successfully without complaint, and i appreciate their customer service, but i can't go on the word of someone who's told me (1) i looked into it and you have a 2TZ-FE, (2) you probably have a 2TZ-FZE, and (3) i don't know whether you have an FE or an FZE, over the course of one day! what other bad information will be politely, courteously delivered? as soon as i say thanks and hang up i realize the contradictions!

    anyway, back to the point, has anyone here run a 2TZ-FZE in a naturally aspirated configuration? how did it go?

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    Re: early (1991-93) vs. later (1994-95) JDM engines

    The comments about the need (at least in the longer term) to use an SC-compatible transmission as well were the eyebrow-raisers for me. I'd also be really leery of using a non-SC ECU. Good luck & don't forget to post the definitive answer to this if you ever do it!

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    Re: early (1991-93) vs. later (1994-95) JDM engines

    i'm not worried about transmissions because that was a matter of handling extra torque from supercharging. i'm talking about running the SC motor without boost, just swapping it in without the supercharger to replace an NA engine. also they're talking about automatic transmissions, so that's not my problem ::] ::]

    wish i had bought a 91-93 FE engine from some typical random anonymous JDM engine warehouse instead of paying for a 94+ FE from the place with warranties and getting this surprise. future readers, if you get a 94+ JDM engine, you really don't know if it's an FZE or not.

    i think i'm going to just go ahead with the installation cause i am sick of waiting and doing hours of research and not having a van to haul my surfboard around booooo poor me can i have some icecream?

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    Re: early (1991-93) vs. later (1994-95) JDM engines

    Quote Originally Posted by silverbox View Post
    i'm not worried about transmissions because that was a matter of handling extra torque from supercharging. i'm talking about running the SC motor without boost, just swapping it in without the supercharger to replace an NA engine. also they're talking about automatic transmissions, so that's not my problem ::] ::]

    wish i had bought a 91-93 FE engine from some typical random anonymous JDM engine warehouse instead of paying for a 94+ FE from the place with warranties and getting this surprise. future readers, if you get a 94+ JDM engine, you really don't know if it's an FZE or not.

    i think i'm going to just go ahead with the installation cause i am sick of waiting and doing hours of research and not having a van to haul my surfboard around booooo poor me can i have some icecream?
    Use your old fuel injectors and ECM. the SC engine itself (block, head, internals) are close enough to run in place of your FE. the cams are slightly different (no overlap), rotating assembly is stronger, and you get piston cooling oil squirters. you also have a half-point lower compression but you won't notice it outside a dyno comparison and the difference from age/wear is greater. Any sensors that don't plug in, swap from your old engine.

    The warranty is likely void since you're installing it in the wrong vehicle. so much for that lol.
    -Russell
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    Re: early (1991-93) vs. later (1994-95) JDM engines

    You don't want to put a 2TZ-FZE without Supercharger in your van. It will work, but to support the supercharger, it uses different (yet stronger) pistons to reduce compression in the block slightly and better handle the added pressure of the supercharger. 2TZ-FZE without S/C will actually put out less power than the N/A engine, which is already a bit underpowered. Unless you don't mind the small drop in power, I recommend sticking with the NA 2TZ-FE. It was used until to 1995.
    Last edited by terbennett; 03-09-2020 at 09:40 AM.

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    Re: early (1991-93) vs. later (1994-95) JDM engines

    i actually really like the idea of having a boost-ready engine in my van, but it is a very low priority right now compared to my need for this expensive repair to work well the first time. this has to be a definite good, proven swap with multiple stories of people who did it themselves in their early-model previas and had it run smoothly and reliably without any big issues. otherwise i am out thousands of dollars and who knows if i can even find another mechanic willing to work on a previa. i think the one i found is ready to be done with this swap and not do another. so i believe i will have to return this engine and get an early-model JDM FE instead.

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