Today at Atelier Kaz - ex-Honda R&D, F1, Indy/CART engineer

Have been working on another NSX for like 2 weeks now but didn't have time updating the blog because
I wanted to disassemble the parts as much as possible in case I had to place extra parts orders that
were not included in the original service menu.
And I'm glad I did, as there were so many extra service items found.


One thing the owner wanted me to look into was the misfire that will only happen (frequent but not always)
when the eng was cold (it's actually the tyre pressure affecting the circumference) and
only at the very beginning of the journey just after leaving his place.

Again, the owner told me that it was not consistent and intermittent but frequent.

Once up to the speed, no further misfire and even after parking the car for a while,
no more issue until parking the car overnight although the owner has other cars so tends to be parked for days/weeks.

As the owner was very busy, he asked the driver from the vehicle transport service to take his NSX to my place.

On arrival, spoke with the driver as I wanted to know whether he felt something or not and if so, whether it was a misfire or hesitation.

He told me that on the day when he collected the car from the owner's place, he did experience the misfire and not hesitation but
after re-fuelling the car with standard (not the super premium) fuel, he never experienced any issues the following day and
it was just pleasure driving this car.

As the weather was too windy and I was more worried about the coolant below MIN level so decided to carry out the Health Check first
before carrying out the test driving session.

I wrote detailed test report for the owner but it was interesting to know how the TCS can be triggered due to several conditions such as
the driving environment, tyre pressure, one of the front w/speed sensor open circuit failure,
some of the algorithms using average front w/speed and not the individual one, TCS failure detection for w/speed sensor
(3sec after one of the front w/speed reaching 10mph) and other factors.

At the end, it was nothing like misfire or hesitation.
It was sharp power/fuel cut for like 0.1sec even at jogging speed and it only happened once out of 3 different test driving sessions.

Not sure it was as the same phenomenon as the owner and the other driver but for them, the very low front tyre pressure (only 1.5kgf/cm2, 21psi)
and the driving condition (must open TH fairly wide almost immediately when start driving) made the situation even worse.


Not going to repeat the long-long report that I sent to the owner but I think I got the full picture and
hope I can fix the issue by replacing the faulty FR w/speed sensor and
using proper tyre pressure.
I could disable the TCS for non-DBW model but then the changes in MOT regulation may cause future issue so would prefer not to.


I don't know this would be the same for the DBW model or the w/speed signal processed through the upgraded ABS but
it would happen with any NSX with non-DBW TCS.


Learnt something new even after knowing this car for years.....



Kaz