Platinum Member
Platinum Member
Find a way to display in Hybrid mode for the specific thread by default.
Or, format in App friendly structure for future proof.
Create '#Tag' page.
Review how it could be displayed in different platform.
Or, may try creating different structure through Admin control panel through requests from the users.
Possibly best waiting until the new platform introduced.
Last edited by Kaz-kzukNA1; 09-01-2025 at 12:29 PM.
Platinum Member
Mot
#MOT MOT
Earlier this week, passed MOT.
94 JDM so 31 years old this year.
Original CATs and already covered 177K miles (284K km).
Drove for a while in 4th gear at moderate speed to keep the ECU in open loop.
Then, back to closed loop and straight onto the emission test.
Easy and never failed.
Time to start looking for the replacement rear tyres.
Don’t like Neova AD08RS and not sure UK will ever receive AD09 for the OEM 16/17 wheel.
Interested in PS5 but when the time comes for the front, it's bit too narrow for my like.
May try Advan Fleva V701 as several owners had good experience but not sure of the wet balance.
I always liked the behaviour of the original AD08 and the AD08R in wet condition.
Probably decide in few months.
Kaz
Platinum Member
Battery Health
#battery battery
#topdon topdon
#batterytester batterytester
During spring and summer time, A/C is always one of the most discussed topic.
During the cold period, it’s the battery.
Last week, started working on the alternator and the gauge cluster but latter part of the week/weekend was just too cold.
Not a problem for my body as I wear fireproof to keep myself warm.
However, since I use my bare hand when dealing with delicate tasks, it just made my finger numb as soon as I touched any metal surface.
So, focused on the electronics component service.
It was also good opportunity to carry out the health check on my 5.5 years old Yuasa battery.
It’s actually related to the reason why I ended up servicing the alternator and the gauge cluster mentioned above.
Mine is YBX5005 and just a lead acid flood battery.
Installed it in Jul/19.
Used to replace the battery every 8 years in UK regardless of the battery condition.
In Japan, due to scorching hot summer, quite low rpm environment and majority of owners using their NSX for short distance journey, many are replacing the battery every few years.
My personal view is that because of the hot summer in recent years here in UK, it has shortened the battery life.
Before replacing the battery in 2019, I always went with the Honda OEM one.
Don’t know who manufactured it.
I think the last one was made in France???
After 7 years, it clearly showed the slow cranking speed and while I could have kept using it, replaced it.
Now using YBX5005.
This specific battery can be out of stock from time to time on Tayna Battery website.
Already experienced twice.
The health check from 2023 and just last weekend.
The car was parked for 45Hrs, outside temperature went down to -5degC but the car was kept inside the garage so didn’t know the actual air temperature inside the garage at the time of testing.
As regularly driven, can’t even remember when was the last time I connected the battery conditioner to this battery.
So, it was charged only through the alternator.
Can’t do direct comparison as so many conditions were different but when I started the engine, for the first time with this battery, the volt gauge went down close to 9V.
Still, managed to start the engine no problem but with slower than usual cranking speed.
This week, much warmer and the voltage stayed just about 10V on every cranking so going to keep using this battery for now.
Should have many months to go with this battery but for the next one, want to try the EFB type.
Yuasa has YBX7005 as the EFB but according to Tayna website, it’s discontinued, although Yuasa still displays it as one of their available model.
Some online shops are showing it as in stock but could be from very old batch.
Will see when the time comes.
If not available, I'll try the EFB from Bosch - S4E40.
Kaz
Hi Kaz,Originally Posted by Kaz-kzukNA1
I have always struggled with emissions being close to the limit for MOT.
Could you please explain further what you mean by the ECU being in open or closed loop and how to achieve this for the best readings on the emissions test please.
Many thanks
Olly
Platinum Member
Nothing special.
In my view, emission test in UK (NI has its own MOT rule) on pre-Euro Standard make/model is fairly reasonable compared to some part of the world.
Please note that if you use aftermarket ECU, sport CAT, bypassed the fuel pump resistor, have crack/leak at the exh system, complicated aftermarket exh backbox design would affect the reading.
There are many research carried out on the chemical used in certain engine oil that could reduce the efficiency of the OEM CAT over time.
Some of the very early NSX models (91 and some 92) require only the non-CAT test.
For the later models with BET (Basic Emission Test) mode, it even allows secondary test in case it failed the initial one.
All the criteria and the procedures can be found in the MOT manual online.
There are lots of good articles, chemical equations and diagrams on how the CAT works on the web so please take a look.
Same goes for the HC, CO and NOx amount below (rich) and above (lean) the lambda window with the effect on the CAT efficiency. You’ll find pretty much all the basic you need to know on the web.
And same for the EFI control.
There are plenty of articles on how the ECU uses open/close loop control based on OEM narrow band O2 sensor and the reason why it aims for the control window mentioned above.
The rich/lean condition for acceleration, fuel economy, NOx reduction, chamber temperature, CAT efficiency, etc are all covered.
I won’t go into detail for IP reason as I don’t even comment in the ECU discussion on Prime or FB group.
Based on these and how the emission test is carried out (test at the idle rpm always follows the higher rpm band first), you’ll know to keep the CAT hot.
No need driving aggressively.
Just keep driving in 4th gear or whatever the gear that you can keep above 2.5K – 3Krpm.
Doesn’t matter if the rpm drops below that window from time to time.
I normally drive at least about 15min on dual carriage way in 4th gear at cruising speed and once heading to the MOT station, use higher rpm band than I normally would.
On arrival, keep the engine running.
Ask the MOT operator to carry out the emission test first.
If you have to wait for your turn, keep the engine running (be careful with the new regulation on running engine unnecessarily) and blip the TH from time to time.
UK has good regulation on fuel quality so unlike the fellow owners in US, we don’t see bad test result at the time of INJ flow rate measurement.
Used to see fuel sample spectrum analysis.
Don’t know the spec of your NSX but if your O2 sensors have covered more than 60K – 100K miles, Bosch recommends replacing them (primary/upper/sensor 1/before CAT ones).
Later model has air assisted INJ and/or secondary air bypass system.
Even thick tube for the air assist passage, be gentle handling them.
The metal pipe held at the side of CYL head for the secondary air system could get cracked so worth checking from time to time.
EGR valve is monitored by the ECU but only for the needle lift and not the actual exh gas amount.
Although it has main effect on the NOx under cruising condition, it will reduce the oxygen and chamber temperature.
Seen CEL being triggered on several NSX for fuel mixture error codes and not related to the EGR but the truth was, it was triggeed because of the specific area of the EGR control.
Cleaning the EGR passage is recommended on high mileage or poor fuel quality area.
I normally replace both O2 sensor at the time of Eng Refresh as it’s so much easier to access them especially the one at the rear bank.
For the EGR, when taking off the intake manifold for the VVIS butterfly service, I look at one of the port/pipe and if full of carbon, I would clean the passage on next big service.
Also, there is one section to be checked for the EGR control but you will first get the CEL not related to the EGR.
Kaz
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