I am planning to inspect a 92 RX-7 FD with a few issues and i was curious, if anyone could give me a hint on what to look for with the car.
My plan is a single turbo 400whp with an RE Amemiya AD-GT Bodykit. For this year i am happy with purchasing a car and getting a single turbo installed. It needs to be a 1992 first registration due to emissions regulations.

The car i am interested in got a new engine in 2021 from a reputable shop i know and i also talked with the shop's owner about the car. It has some nice parts like a V-mount intercooler, two stroke oil system, electrical mirrors on the fender, tein suspension,Blitz Nur spec exhaust and quick-swap 200 cell cat but most importantly: It has a german registration with all the mentioned parts and more approved in the documents which costs around 4.000 Euros alone (only documents, no parts).

Issue 1 and 2: Engine dies off and spliced harness
It currently just idles for 5 seconds and then dies. Starts almost instantly according to owner tho. I am pretty sure the engine itself is ok, it was built by a reputable shop and made only 10.000kms within the last 5 years on 0,8bar, stock twins, no port. The car runs on an old adaptronic and according to the owner, the car dies off due to sensor issues. Electrical seems to be in a rough shape in general also due to a always on brake light and probably also because the harness was cut when installing the adaptronic (previous owner did that). I want to go with an haltech 1500 for my conversion, preferred the plug n play which would not work here. Anyone know how much a new harness costs and where to buy? Didn't find one from nengun in the catalogue and i dont want to use the haltech harness since it seems quite complicated. I want a street and track, not track only car in the End.

Issue 3: Collision damage
It also had a collision with a scooter a few weeks back, which left the front fender in bad shape. The front is less of a concern for me, as fenders and bumper would be swapped for RE fenders anyway. The rear fenders however leave me unsure if the RE Amemiya fenders will fit with the existing cutouts. Any advice here is highly appreciated.


So i am curious on your opinions. He is asking 26.900 Euros and it is the only 1992 on the german market for the past half year, although i am also searching in japan (dealers and auctions).

 

Hard pass.... go to auction and get one. Never buy an FD with unknown electrical problems that are simply written off as easy fixes. If it's easy...... then fix it before you try and sell it. It's deeper than that and they know it. Just go to auction

 

If you're willing to put in the money and work to correct the issues, and being that Germany has some crazy restrictions that makes this car fit most of the requirements, it might end up being worth it.

The adaptronics stopped being supported a few years ago, and were known to have driver issues in the boards. An upgrade to a haltech might be mandatory to fix that issue alone. The other electrical gremlins could signal a lot of frustration and diagnosing from you, if you're willing to do it.

 

That was my first idea as well. But the more i dig into all the stuff i want to modify on the car, more i come to the realization that the only two things i am afraid of is dead engine right after purchase and unknown electrical stuff. I can't find a price for a new OEM harness, which makes even the price calculation hard to do.


My second thought. Even the shop who did the engine back in 2021 said the electrical harness is a mess. Shop owner told me it could be done by myself with an OEM harness and a high frustration tolerance lol.

Maybe i am just gonna try and lowball. For 20k Euros it would be cheaper than almost anything i could get out of japan plus it already has the expensive paperwork done. I am still trying to stay within my 45k Euro budget, let's see how it goes.

 

Electrical harnesses, other than the emissions, went extinct about 20 years ago, that's why you won't find a price.

Could pay you to replace that harness if it's the original and everything else is close to stock.....did the workshop specify that one, or just say generally the wiring was crap?

The V mount with relocated relay box, may be an issue if done like some out there, half the stuff needed to run the engine goes via that circuitous route. Not unknown for aftermarket audio and security installs to also take a poop inside the cabin too.

Last times with a 92, even with that car only ~ a decade old at that stage, easier to find complete body/engine wiring harness for a 95 off yahoo and change bits and pieces (ABS, etc). Last swap following a fire was installing a version 6 complete system in a version 3 car, again at that point, nothing available for a car of that age (10? years ago)

 

That explains why i can't find anything. I am a bit spoiled by working on my BMW the last years, where 99% of the parts available and delivered within 5 days. I stumbled across wiring specialists, maybe i will contact them, their harness looks like it retains the stock routes but with better quality.
According to the shop the harness has been "cut up" at some point in his life to make the Adaptronic ECU work. The shop owner told to replace the wiring harness if i ever want i to be somewhat reliable.

 

I have recently seen FD Version 1 engine/emissions harnesses on Buyee "new in box". Don't know if still there. Also the battery/alternator harness I have seen on US sites. The LHD and RHD harnesses for Version 1 cars should be close in regard to that harness.

But I suspect your original harnesses were already highly modified.

So an OEM one, new or old, might also need to match the modification.

If you trully plan to reconstitute the OEM set-up, best budget $5000 and buy almost all new stuff for the set-up (Solenoids, coils, all the sensors, vacuum lines, etc.) any 32 year old part is likely to fail very soon.,

 

Sounds a bit strange with a PnP ECU, unless a few of the vacant connector pins are being used for extra input/outputs and that's the reference.

Anyhow, might be well advised to get a new emissions harness if it's the original crusty 35 year old one full of gremlins and the usual cooked injector/CAS/sensor plugs on top of the engine. The twins can be retained that way until the single is ready and the haltech still has the early plug patch harness available as I understand it. Hopefully the front harness and dash(?) connectors at the ECU haven't been too fiddled with.

 

Engine harnesses for RHD cars can be had on eBay or Buyee brand-new for about $1000USD. Probably less if you're avoiding the US tariffs. I believe the part number you'd want for the 8-bit engine harness is N3A7-18-05ZG. But don't spend $1000 on my word alone.

I have a Wiring Specialties harness coming myself due in next Monday. I've heard good things and I'll let you know what I think, but I figure it had to be better than my crusty, hard-as-a-rock, every-clip-broken OEM harness.

If you have any issues with the internal dash harnesses those can be harder to find and/or more expensive despite being 'simpler'. And if you need the mega sized "horseshoe" harness that runs around the entire engine bay and in/out of both sides of the cabin, you are out of luck altogether.

And Redbul's not exaggerating the cost of rejuvenating the electronics. it's a deep rabbit hole to go down that is very, VERY expensive if you're really dead-set on replacing all the questionable (if not already broken) electricals in these cars. Every other day I'm putting in another $250 order for a new sensor, hose, gasket, etc. I have little doubt that, all-in, $5000 is not an exaggeration at all.

 

The original harness has been modified but i don't know how much. Fact is, the car currently dies after 5 seconds in idle and according to the shop the electronics "had some serious issues" when the car was in the shop back in 2021. However, nothing has been changed and it ran till half a year ago.


I think renewing cables after 35 years isn't a bad idea at all. However i would prefer to do that if everything works before already. I also hope the rest is ok, but i don't think so: The 5 extra gauges and the panel in the middle (it is to check if the two stroke oil system is working) probabaly needed some fiddleing.



I also already contacted WiringSpecialties and i think their OEM+ harness looks and sounds great (curious how you like it in person, let me know) and i could use a plug and play patch adapter. Only downside: If i go single turbo, quite a few of those plugs will hang around unused and there currently is no Haltech Nexus S2 terminated harness for the FD. My tuner told me to better choose the Nexus S2 and tbh, it is not a big price difference at all. Yeah propably, 5.000€ is quickly spent on electronics. I come from working on a BMW, those small sensors and cables are adding up.

 

You can order a CarVX which will give you some history of the car while in Japan.

https://carvx.jp/

 

This is from the Version 1 wiring diagrams. It shows the harness but good luck following the diagram. There is not a single schematic that shows all the wires and connectors in one diagram. Note that in earlier JDM and USDM manuals the "engine" harness is called the Emissions Harness and the starter circuit harness is called the Engine Harness. This is changed to Engine harness (1) and Engine Harness (2) in later JDM manuuals.

 

You can get all the jDM wiring manuals here:

https://www.rx7club.com/3rd-gen-gene...002-a-1127911/

Password is found in the file name.

 

Here is an early JDM emissions harness. My notes says it is missing one connector (I will let you guess which one). uSDM equivalent will have extra connectors for certain emissions equipment.

 

Current number looks to be N3A7-18-05ZG, which looks to be available https://www.amayama.com/en/part/mazda/n3a71805zg

i'd go look at it, electrical gremlin covers a lot of ground, and it could be a tuning problem, or something mechanical along with any harness thing.
also probably the case that it'll scare everyone else off, and car will be less monies.

 

I will check it out in 10 days, told the seller i can only pay a fairly low price, compared to his initial asking pric due to electronics and the minor collision damage and he said he is open for it.
Car ran fine in 2021 when it was tuned with the 0.8 bar on stock twins and is was running well mid 2025 when the quick-swap cat was installed.
That part number looks good, i will check it. However i could also get the wiring specilities OEM+ harness which is a bit more sturdy and better looking for the same money.
Hopefully i will know more about how much this fun can cost me before i go to the negotiations. I am also unsure because of the rear fenders, depending on how much they were cut, the panel may be not suitabel for the Re Amemiya AD-GT kit.

That is great, didn't know this existed for japan!

That looks like absolute nightmare fuel to me, i don't know why electronic harnesses turn me off that much
I'd rather work on some rusted suspension parts or similar than on a clean harness. But knowing i may be looking for an emissions harness is a great step forward.
Due to my absolute lack of knowledge about these things i would guess something about the air sensor for the second turbo?

 

Yes there is no air sensor for the second turbo.

There is a MAP sensor mounted on the firewall adjacent the top right (as you face it) of the UIM.

You could check it is in spec.

There is a O2 Sensor on the top section of the downpipe.

There is an air temperature sensor on the underside of the UIM.

All of these can be checked to see if they are in spec.

Prior owner may have installed an AFR sensor (usually before the Cat on the downpipe).

 

CarVX seems ot be new. There was also "autocheckjp.com" but they seem to have gone quiet. There service was better than CarVX.

 

Good info here, thank you. As of now, i would probably buy the Wiring Specialities OEM+ harness and the Nexus S2 PnP adapter - if i end up buying the car next week, we will see.

 

I wouldn’t do it unless you’re fine not driving it for a while, and plan on getting a new harness/all the parts required for your build immediately.

i bought mine from a guy in Florida via EBay. Not only was the guy a huge ricer POS that didn’t include items from the pictures, he hacked up the harness in laughably bad ways. I would wait.

 

I will have to see the car for myself. I am skeptical but if it comes cheap, i will consider it.
The car needs to run by october or latest november so i can get it registered with all the modifications.

 

Understood. Beware timelines too. I’m dealing with missing numerous timelines because parts I ordered haven’t showed up a year and a half later. Try to confirm you will have the parts in hand (especially if they’re coming from another country). I’ve received parts from places like rhdjapan and nengun fast, with no problems!

other places not so much. Hope the car works out!

 

Thanks! It is quite a challenge and i hope everything will work out. If it won't be this specific car i have given myself time till april to find a car with Re Amemiya AD-GT Bodykit and maybe even a single turbo in japan but if i don't, i will have to buy whatever decent comes to the auctions and 1992 first registration so i can meet my deadline.
Turbokit if needed comes from turblown, they assured me 90% of the requested parts i want are already in stock and can be in germany within 6-8 weeks. ECU from haltech won't be an issue.

 

Haltech, even when back ordered came within a month. My current build thread is detailing what has been happening with the stuff I’ve been waiting on from Turblown. I hope it’s actually in stock and you get your stuff before your deadline. Beware the “x weeks” response and plan for double that

 

Yeah, to be fair that is my biggest concern together with a dead engine right after purchase lol. Fingers crossed, i am just as afraid of my plans as i am looking forward to the car.