View RSS Feed

Today at Atelier Kaz - Private NSX Enthusiast, ex-Honda R&D engineer with F1, Indy/CART background

Fuel Pump Resistor 01

Rate this Entry


















Over the weekend, was about to return another NSX to the owner.
While I was doing the final inspection, noticed sudden dip in idle rpm.

I know this NSX has hunting rpm phenomenon when re-starting with engine hot and
only when engine load was changed such as A/C On-Off, engaging/disengaging the CL, etc.

The rpm dip was huge and randomly fluctuating so different phenomenon from the hunting rpm.
From the way the rpm behaved, it was happening at multiple cyl randomly and without any 'pop' so
more of fuel delivery related than the IG.

As I replaced the fuel filter, I thought there was a problem with the new OEM one as
Honda changed the design and possibly the manufacture as well.

However, when replaced the fuel filter, the fuel pressure was fine and fired up the engine many times so
very unlikely to be the cause but still, something in the fuel supply was causing this.

With very low mileage and close to final production year, very unlikely to be the fuel pump or the INJ related.










After some investigation, I found that the issue only happens if I straighten the wire at the fuel pump resistor and
never happens if kept sharply bent that looked suspicious compared to other NSX.


Many owners experienced this resistor box failure so I replaced mine long time ago and kept the good used one in the boot as an emergency spare.
I also carry 090 short circuit wire so that I can bypass this resistor box in case of fuel pump fatigue and force the fuel pump at max speed.

So, quickly replaced the fuel pump resistor with my emergency one and all was fine.











When I looked at the failed resistor, as mentioned above, the bracket holding the wire was bent sharply, almost like on purposely.
Also, the bracket was really rusty.

The wires felt very stiff, in fact too stiff compared to mine and almost like solid material.














As suspected, if I wiggle the wire close to the resistor box, sometimes it created open circuit but other times, it was showing good resistance value.














For some reason, Honda slightly changed the resistor figure from 97+ but as far as I know, the fuel pump itself stayed the same.
In fact, if you place the order now, you will receive same fuel pump package for all year model.
At least outside of Japan, you can no longer place the order for the 91–96 resistor box.














There was suspicious trace of rust where one of the wire was attached to the resistor terminal.







Any way, managed to return the NSX to the owner over the weekend by installing my emergency spare while waiting for the new parts to arrive from Japan.
















Updated 13-06-2017 at 05:50 PM by Kaz-kzukNA1 (Character code issue for quotation mark [ ' ].)

Categories
Personal View/Self Talk , Fuel and Emissions , Electronics

Comments