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

Started to work on another NSX.
The service menu is to carry out the Eng Refresh and replace
the LMA with the one from Science of Speed (SoS), flush ABS and etc.

The owner is using his NSX as the main car so it’s his everyday car.
He is exercising the ABS regularly.

Recently, he made some modification to the header/exhaust area
and since then, he lost about 20% of fuel mileage and also
started to get CEL when driving really hard while accelerating towards
the limit but no CEL at cruising.


So, before start of the service and going out for
the test driving session, carried out the general check up.


First thing I noticed was the tyre pressure.
All four tyres were at different pressure and right side was
higher than the left one.
Probably adjusted while the left side of the car was
under the direct sun light???
Any way, adjusted to the OEM spec and will keep eye on
all four tyres in case of slow puncture.


Not so comfortable going through the roundabout but
probably it’s something to do with the tyre or the suspension area.


Lots of cabin noise from the interior panels.


This NSX is F-matic and the owner mentioned about some
slip when going into 3rd gear.
I didn’t feel it during the quick 15min test driving session but also
it’s due to the way I drive Honda AT gbox.

Honda AT doesn’t use planetary gears like other production cars and
it has multiple friction discs at each gears.
AT controller brain estimates the current torque and controls the
ATF pressure to let the multiple discs to slip before engaging to
the next gear.

So, when driving Honda AT models, I tend to lift the TH pedal a bit to
reduce the engine torque while forcing the AT controller to shift to
the next gear. It's similar to what you will do when driving the MT model.

Because of this Honda specific design, eventually, all Honda AT box will
require some level of service after lots and lots of mileage.

The friction discs will loose their friction materials and the bits came off
from the discs will block the strainer resulting in loss of hydraulic pressure
and eventually, you will loose the drive.

If you park the car for a while, you will be able to drive again because
the debris will fell off from the meshed strainer until it is blocked again.


For street driving condition, most of the slip will happen at the 3rd gear.


This is what’s happening when the slip happens and eventually
loosing the drive.

All photos are courtesy of Mr Toyoizumi at KSP Engineering, Japan.






Inside of AT gbox.







The friction disc material blocking the strainer causing the loss of drive.





The cause of the slip at the 3rd gear.







This disc lost its friction material completely.










Imagine what will happen if those debris were trapped
inside these complicated maze like valve body.



While under slow cruising mode at about 30mph,
noticed that the Eng oil pressure gauge was showing
more than 6kg.
At idle rpm, it was at 2kg.
Not sure what kind of eng oil in there but interesting.
Not a problem though.


The brake calipers are very rusty and most of the
bleeder plugs lost their original shape.
I think I’m going to have fun bleeding the brake at the end
of the service.
One thing you really don’t want to do is to strip the
bleeder if it was over torqued in the past and then seized
due to heavy corrosion.


No CEL so far but will read the error code later.