fuel pump resistor bypass

[metsuki]

Hi everyone,
long story short, my 93 nsx was experiancing some acceleration hesitations, sort of missfires, and not so much power from the day i bought it.
i was blaming my old coils, or even a bad timing belt job....but i try the fuel pump resistor bypass and bingo, everything seems to become fine.
what can i conclude with this?
do i need a new pump? do i need a new resistor? do i need both?
can i drive the car with the bypass for a long time without issues?

thank's a lot guys

[goldnsx]

Most likely, your fuel pump is dying. How long you can drive with the old one? Don't know. But it should last a little bit longer.

OEM is expensive, aftermarket is junk if you are unlucky. With the labor and time involved to change it I'd go the bullet proof way. Don't ask me how I know. Or are you planning going forced induction?

[metsuki]

thank you goldnsx,
the car will remain stock.
so there is no problem driving the car with the bypass?
i drive the car maybe 2-3000 miles a year, if it can buy me some precious time...

[darock]

I drove one complete season now with the bypassed resistor.

The only issue I had was the emission test during the yearly inspection. The engine runs rich at idle. It seems that it has a bit too much fuel pressure.

I have to do a back to back testing next spring with the resistor bypassed and connected.

Other than that, the car runs strong.

Bernhard

[goldnsx]

thank you goldnsx,
the car will remain stock.
so there is no problem driving the car with the bypass?
i drive the car maybe 2-3000 miles a year, if it can buy me some precious time...

The mechanic of the fuel pump inside wears out over time. By bypassing the resistor this process is now accelerated. But at 2-3000 miles a year you might have 10 years to go but don't blame me if it doesn't. The next time you will notice a problem is in the high fuel demand range -> high rpms, high load. That's where you want to guarranty a healthy fuel supply for sure.

[metsuki]

just to let everyone know, finally after replacing all my coils, i can tell you that my problems was coming from them and not from a fuel deliverance issue.

[metsuki]

Hi everyone, and happy new years!

i come back to this thread because the problem was not solve in fact...

the hesitations are gone only for few miles after unpluging the clock fuse.
i don't understand what can cause that???
it seems the car run fine as long as the ECU is learning and then the hesitations come back (around 2000rpm mostly, and at very light throttle)

in two years i changed to solve this:

6x spark plugs
6x coil pack
2x O2 sensor
SS exhaust manifold
SS cats delete
SS exaust TAITEC

it is not a big issue, i can live with it, but i feel the car is not as smooth and powerfull it could/shoul be.

[metsuki]

In fact I just put back the bypass yesterday and the car still have the same hesitations at light throttle. Just like I was playing with the throttle very softly.
And If I press hard on the throttle at very low Rev, the car nearly stop and then rush.
Do you think the fuel pump is just so shot that even with the bypass it do not feed the engine sufficiently?

[goldnsx]

Did you measure the fuel pressure? What's the pressure at idle? That's the first thing I'd check.

Not sure about the fuel pressure regulator...

[britlude]

i'm having the same issues at the moment, i checked my fuel pressure and that seemed within spec at both pump resistor in line and bypassed, and with the pressure regulator vac line disconnected, and connected....

the hesitation i have isn't regular and repeatable enough to fault find easily, but as mine is JDM it has temp sensors in the cats. these flagged up an over-temp condition on the motorway. this was after a brief period (seconds) of the engine 'missing' while on a constant cruise on a slight incline. this was was experienced with AND without the fuel resistor in line with the pump

with the help of Kaz's knowledge, the JDM overtemp warning light implies raw fuel at the cats, burning in the exhaust, heating the cats. as i checked the fuel pressure, i didn't see any evidence over fuelling, so i'm leaning towards an ignition issue.

to that end i have a couple of used ignitors winging their way to me, so i can eliminate that side of things.