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New J-Spec NSX, some pics and questions

5 December 2018
I've been working on my newly imported J-Spec NSX and have a couple of questions I hope you can help me out with. We're currently in lockdown in Melbourne Australia due to our friend Covid-19 so I can't even take some nice pics of the exterior since I got it, this is about all I can do sitting in my cramped garage:
<img src=http://www.j-spec.com.au/customers/NSX/nsx_31.jpg>

<img src=http://www.j-spec.com.au/customers/NSX/nsx_32.jpg>

I'm soooo looking forward to taking some exterior pics once I get it out, not to mention actually drive it!

Ok, on to some questions!

1) Running an ECU diagnostic I'm getting codes 43/44 (front/rear fuel supply system) and 1/2 (front/rear hot O2 sensors), I'm guessing this is basically saying I need to replace the O2 sensors. My car has some aftermarket manifolds with the O2 sensors running braided lines right up and into the trunk as in the pics below. Is this normal? If I buy some O2 sensors to replace these will I need to make some extra changes to fit them?
<img src=http://www.j-spec.com.au/customers/NSX/nsx_33.jpg>

<img src=http://www.j-spec.com.au/customers/NSX/nsx_34.jpg>

<img src=http://www.j-spec.com.au/customers/NSX/nsx_35.jpg>

2) This lens cleaning liquid vial was in my tool kit. Is this some random item or is it actually NSX related?
<img src=http://www.j-spec.com.au/customers/NSX/nsx_36.jpg>

3) This relay was in my tool kit as well, what might this be for?
<img src=http://www.j-spec.com.au/customers/NSX/nsx_37.jpg>

4) I discovered my car has a Type R shift knob and shift mechanism. How does this differ from the standard unit? Is it just a shorter throw?
<img src=http://www.j-spec.com.au/customers/NSX/nsx_38.jpg>

5) Should this round loose plastic piece be just floating in the clutch reservoir?
<img src=http://www.j-spec.com.au/customers/NSX/nsx_39.jpg>

6) Any idea what this white powder is from on this line that goes to the fuel filter? There is no fuel leak and never any fuel smell.
<img src=http://www.j-spec.com.au/customers/NSX/nsx_40.jpg>

7) What are these two disconnected plugs for? This is in the front left corner of the trunk (the opposite side to the CD stacker). The bundled blue wiring looks like it's aftermarket but the brown/orange plug looks factory. Might this be related to my stereo not working? I know these have common problems, here are the symptoms. It turns on but I can get no audio out of it from the radio (I don't have a CD magazine or cassette tape to test), with the car off I get a very faint white noise hiss from the speakers with the radio turned on that doesn't go up or down in intensity if I adjust the volume.
<img src=http://www.j-spec.com.au/customers/NSX/nsx_41.jpg>

8) What am I losing with the cut wires in the bottom left corner of this photo? Everything seems to work ok (my car has no fog lights) so what might these do?
<img src=http://www.j-spec.com.au/customers/NSX/nsx_42.jpg>

9) No pic, but how do I remove the chrome handbrake button?

10) My car came with a Momo Zagato Design steering wheel and obviously an NSX boss kit and I also have a Momo Race in excellent condition off another car I can't even remember from years ago (R33 Skyline maybe), are these in demand? I think I'm going to stick with my standard wheel.
<img src=http://www.j-spec.com.au/customers/NSX/nsx_43.jpg>

Thanks guys

- Ben
Perhaps JDM market vehicles have an odd O2 sensor; but, my gut reaction is that those look more like exhaust pyrometers (thermocouples) rather than O2 sensors (at least the O2 sensors that I have seen). Have a look at the connectors in the trunk. Are the individual connectors two wires? If so, chances are they are a pyrometer which would definitely explain your 1/2 error codes. Since you are in lock-down, it would be useful to trace the wires from the sensors to see what, if anything they are connected to. This may give you a clue as to what is going on.

You did not specify the year of your vehicle; but, I an guessing it is na1 (I don't know when and if JDM got OBDII). If you can't find an RHD service manual, there are links on Prime to .pdf copies of the 1991 LHD service manual which won't be perfect; but, will be better than nothing. In the Electrical section of the service manual you will find diagrams which are a map of the wiring harnesses in the car and call out the location and function of every connector in the car. You can use that to find the location of the stock O2 sensor plugs which should be up closer to the top of the engine (I have a 2000 na2 / 4 sensors so can't advise on the location of stuff for an na1). Find those original 02 sensor plugs and if they are dangling loose that will confirm that the factory 02 sensors have been deleted. This will then lead to the question that if the original 02 sensors have been deleted has the ECU been remapped / rechipped or otherwise modified.

The floaty thing in the clutch reservoir definitely does not exist on my 2000 LHD na2 NSX. Perhaps a feature on JDM RHD cars?

No idea what the white powder is. I hope it is not suppressant from a fire extinguisher. Does it just brush off?

That multipin plug in the trunk is stock. My 2000 has it. I expect it is for the optional cellular telephone option.

The LHD wire harness is obviously different than the LHD harness up front; but, I am smelling a very crude ABS delete associated with those chopped wires. The ABS is the unit just below and connected to the brake master cylinder with hydraulic lines. If there are no electrical connections to the ABS unit then your car has been the victim of a hack job ABS delete. You have my sympathies.

Did I mention the factory service manual? Get one because I think you are going to need it. Welcome to the world of inheriting somebody else's creative ideas :smile:.
Based on what I can see in your photo, your JDM NSX is NA1-100type and 91 year model spec.
Your NSX left the factory with R12 spec A/C and the heater core coolant pipe is of early model spec.

1: Braided wire sensor
These are the Exh temperature sensor and not the O2.
Until around mid-'90s, all cars in Japan including the non-JDM ones had to be equipped with some sort of high Exh temperature warning indicator/alarm in order to meet the MOT regulation.

However, the law changed over the time and eventually, this sensor was no longer required.
On JDM NSX, I think it was removed from around 99/00 model.

You have aftermarket header so the O2 sensors would be at the upper stream before the CAT.

These error codes are just telling you that the O2 sensor saw out of the spec voltage readings.
Very unusual for both sensors to fail or read abnormal figures at the same time.
Your NSX left Japan with nearly empty fuel tank and most likely, power cycled at some point.

Since you have already read the error codes, just reset the ECU and carry out another test driving session once the lockdown is over.
Then, start proper diagnosis from there.

2: Lens cleaning liquid
Not OEM and only 7cc so very unlikely to be designed for automotive usage.
Normally, people uses it for cleaning the plastic headlight cover, etc as it can turn into yellow-ish colour.
Possibly part of aftermarket CD player pickup cleaner if you have CD changer inside the boot.

3: Denso 056700-7330 Relay
This relay is used at several places inside the cabin.
Most likely, someone replaced the Fuel Pump Relay.
It bypasses the fuel pump resistor to force the fuel pump into high speed mode under condition mapped by the manifold pressure and rpm.

4: Shift knob and lever
If OEM, it's slightly shorter and obviously in metal and not in leather.
You don't want going any shorter.

5: Float inside the CL reservoir
OEM and standard until upto around 96 models.
You also have some sort of BR master cyl stopper.

6: White powder like marking around fuel line, filter
Standard procedure for the leak detection.
Almost the same spray used as part of the crack/marker detection chemicals.

By the way, the pipe to the fuel filter is kinked/bent causing extra stress on the pipe/hose body.
Typical when someone tightens the 17mm banjo bolt on the fuel filter without supporting it.
There is a marker on the OEM fuel filter that should point to the specific position of the holder bracket.
Hard to explain without showing you the photo so may be later.

7: Black DIN conn. & Brown 4pin 250 conn.
These are for the optional car telephone accessory.
The one with the huge handset.
The brown conn. is good place for getting power inside the boot.

The blue thick one is actually the DIN extension cable for the CD changer at the right side.

Your audio issue could be the famous Bose speaker AMP failure, head unit issue, etc.
If you can hear faint hiss even when IGSW in P0 OFF position, check the speaker AMP relay under the bonnet/hood.
Famous for sticking or even melting the relay box.
Same goes for the rad fan, blower motor, conderser fan relays.

8: Multiple cut wires
You are very lucky to have the later spec one body ABS.
Very popular upgrade in Japan.
Night and day difference from the original slow, troublesome and primitive ABS.
In my view, it even has dangerous design flaw.

Because no one goes back to the classic ABS, it's quite common to cut all original ABS wires in Japan although normally, it will be done in different way and hidden to prevent eyesore appearance.

9: Parking brake lever button
Use strap wrench or thick non-slip rubber.
Fairly tight so be careful not to slip and scuff other leather material.

10: Steering wheel
The balance between the demand and supply.


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8: Multiple cut wires
You are very lucky to have the later spec one body ABS.
Very popular upgrade in Japan.
Night and day difference from the original slow, troublesome and primitive ABS.
In my view, it even has dangerous design flaw.

Because no one goes back to the classic ABS, it's quite common to cut all original ABS wires in Japan although normally, it will be done in different way and hidden to prevent eyesore appearance.


I was thinking that is not the late 2000+ ABS unit (it sure doesn't look like mine), then I realized that it is flipped front to back. Normal for RHD cars compared to LHD?
Hi Ben,
Congratulations on the car. We have a few JDM cars here in Australia, probably about 30 as a quess. Having Kaz answer your questions is excellent! Kaz is a NSX guru and has been extremely helpful to the NSX community worldwide. I look forward to meeting him in person one day to thank him for his efforts. Feel free to contact me anytime about the Honda Sports Car Club of Australia, which has lots of NSX members nation wide. At the moment we are doing just local runs and Zoom meetings which have been very successful. Cheers Scott

Yes, Old Guy everything forward of the seat backs is swapped for LHD to RHD...I think, Plus the engine bay hold open strut!
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Super nice JDM stocker. It is so nice, I'll bet it went through a Factory Refresh in the past few years.

WhrdNSX is also in Melbourne and he imports a container a year of JDM parts. You two might get along great.

regarding the temperature sensors, there is a red warning lamp on the upper right that looks like a catalytic converter that monitors those sensors.


Can you tell me what connector is under the glove box for the keyless? I'm trying to document the early JDM and any help is appreciated.
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Thanks for the responses, I just saw wires sticking out of sensors in the exhaust and figured they must O2 sensors... silly me. I've owned a LOT of JDM imports from the 90's in my time, I should have recognized that as the sensor for the cat over temp warning lights as on most Nissans and others from the era.

My car has what looks to me like a later model ABS system swap and ABS definitely does kick in, so those cut wires must be part of the original system being bypassed with the new system, they just could have done a neater job of it, so I'll fix that.

NSX9: my car is on club reg so I'm already a member of the Honda Car Club of Victoria. Not everything is mirrored on RHD cars, the fuses in the interior are still on the same side for example.

Drew: I don't think mine has had any significant refresh done, it was just a nice, well looked after car. I import cars for a living (I have several other NSX's on the way into Australia for customers) and a lot of them in Japan are actually not at all good cars now, I had to look at quite a lot of them before finding mine. Interesting comment though regarding a Factory Refresh, I just saw this on a car that I was looking at for a customer a few weeks ago, is this a Honda thing?

<img src=http://www.j-spec.com.au/customers/NSX/nsx_44.jpg>

That was on a red manual with about 25,000 miles on it. A nice condition completely standard 1990 but didn't look like it had any cosmetic refresh (original old leather, etc), mechanicals all seemed fine.

Is this below a photo of what you wanted?

<img src=http://www.j-spec.com.au/customers/NSX/nsx_45.jpg>

Mine is a 1990 and didn't come with any keyless entry fob. Should it?

J-Spec Imports
Yeah, those photos added to my KB library!

That Keyless is super cool. Can you post what is on the other end of that harness please, how does it connect to the body?

That is the fabled ~1990 Accord keyless unit "08e52-sm5-1000-01". The remotes should be 08e52-sm5-1000-02 and use 318mhz, same as the NSX/Legend. It has the USDM FCC ID is GJ8 08E60-02, but a 30 pin green connector.

So something new to me, but that doesn't mean much. More here: http://www.nsxprime.com/forum/showthread.php/109139-91-keyless-entry-the-truth/page5


The NSX Factory Refresh has many levels, from replacing the soft parts to completely rebuilding with a color change (based on the JP translation). The refresh can reset the registration costs, where in JP they go up as the car gets older.


My JDM just had the soft parts replaced as the inspections start to get very rigid and harsh...
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This is a pic of where the cabling goes from the green connector, it's basically up under the glovebox (remember this is a RHD car) and continues up to near the trunk on/off switch from what I can feel with my fingers, to see any more I'd have have to disassemble the glovebox or dashboard parts around it.
<img src=http://www.j-spec.com.au/customers/NSX/nsx_46.jpg>

Is that what you wanted to find out?

Also I found this on the other side of the car in the driver's footwell, this is very hard to actually see. I'm terrified to go messing with this given that I don't have a remote fob to disarm anything and I'm not sure what all this does!
<img src=http://www.j-spec.com.au/customers/NSX/nsx_47.jpg>

I'm not sure what you're trying to learn here but hope it helps :)

So my car has keyless entry, and if so what remote would I need and how would I program it?

J-Spec Imports
Very nice car, it's in great condition! Hope you have been enjoying it.

Sorry to hijack a the thread for a question, I came across this looking for more information about the cat temp sensors for my 93 JDM car.

Sidenote, there was another thread in my search, where Kaz mentioned the same sensors on a uk forum in 2012. Amazing to see Kaz still sharing such a wealth of knowledge! Wow, thank you @Kaz-kzukNA1!

Ok, so.. hoping to get some help. I purchased an aftermarket catback with two highflow cats, which don't have the bungs for these temp sensors. I have tried a few workshops and exhaust places to see if they could weld on bungs, but the fittings needed aren't common, so no one could help.

I was wondering (before I look at fabrication or source the right fitting).. Is there a way I could disable the sensors so the car is "happy" without them?

If I run the car with the plugs connected in the trunk, but sensors not in the exhaust, unsurprisingly I get a warning light in the top left after a 20 minute drive.

When I just unplug them in the trunk, I don't get far down the road before the warning lights up.

Any advice would be much appreciated.
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re: cat heat sensors. You need to convince somebody with a JDM Service Manual (Hi Kaz) to post the sensor test procedure. I have those too in my 1993 too and I have not researched them.

If there are no driveability issues, and the best I can determine is that they trigger a warning lamp in the upper right of the cluster. If so, it is not too difficult to depin the terminal or remove that particular warning light from the cluster. Not a great solution.

I can measure the resistance of the sensors after operation, but currently, my car is down until I get time for a timing belt.


I also want to make a correction for the NA1-100 security system. It's been two years of being A COVID Project (TM) and I have learned a bit.

The NA1-100 cars DO NOT have a built-in Security Control Unit. A complicated OEM harness was added that stretched from under the steering wheel, behind the stereo, and into the passenger side dash where it connected to a metal box. It also included a starter cut relay system and an LED to the center console JDM switch panel (later cars had a LED on the driver door next to the lock).

The correct remote for the IR system is 08E62-SL0-00001 which is NLA. Try places like MITA or buyee.jp if you are a purist. Every once and a while I see the remnants of these systems for sale, but I have yet to see any NSX remote transmitter for sale in years. The system was apparently terrible and did not work well on day one, so probably not worth the trouble or expense. I suspect the system can be retrofitted with an RF remote receiver for somebody technical (I'll put this on my Next Pandemic Project list).

What is pictured in [MENTION=35392]Blipman[/MENTION]'s car is the OEM add-on system, which uses an IR receiver on the drivers door. The control panel for this system is the switch panel that is located under the driver's bolster.

(I have a keyless system produced that I will be selling soon that is plug-and-play for keyless, trunk release, and light flash. Still in process with installation instructions and user testing.)
Although I received the notification for other threads from the server, looks like the 'mention' feature didn't work on this occasion.
No notification received for this one.
The last one I got was from the 16th.

Anyway, glad I revisited the site and found this.
[MENTION=32665]Skysthelimit[/MENTION] , I have a feeling that you are getting the CEL and not the Exh high temperature warning.
Please read the error code.

The exh temperature warning is at the right top section of the gauge cluster and it's red.
The CEL is at the left side and below the alternator charging warning. It's yellow.

If I remember correctly, if you have triggered the exh temperature warning, you 'may' get some sort of 'tone/alarm' sound to notify the driver but not 100% sure on this.

The exh temperature is not used by the EFI control at the ECU.
It's not even connected to it.

The temperature sensors are connected to the ICU (Integrated Control Unit) at the passenger side fuse panel.
The ICU is the only one that can trigger the exh high temperature warning.
The chime/buzzer is also mounted on the ICU.

And even if you have disconnected the temperature sensors at the connector inside the boot/trunk or removed them from the CAT, it won't trigger any warning lights.

So, most likely, you are getting the CEL and it's caused by something else and not by the exh temperature sensors.
Thus, please read the error code.

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Thank you very much for your well explained response.

You are correct, the CEL is what lights up. We assumed, because the warning light happened after the high flow cats and catback install, that the disconnected temp sensors was the cause.
I will try to check error codes. I wonder, would an exhaust leak cause a CEL?

Thank you again for sharing your knowledge.
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