Riching Out Problem

[Alkemist]

Hey. Have a GTR fuel pump in my Cef. Obviously it always whines, and even louder under acceleration. Now here's the problem...

When the car is idle, can hear the fuel pump stay in 'hi-flow' mode, sometimes cutting in and out of hi and low flow. This eventually floods the cylinders and fouls the plugs. Revs sometimes remain at say 2000rpm, other times revs go hunting, dropping to say 600, then lifting to 1500.

What could be causing this?

Guessing, Ignition Module, ECU or o2 Sensor?

Thanks,

Jason

[R31Nismoid]

It shouldn't flood if the FPR is working correctly - thats it's job.

I've had hard wired pumps and ECU controlled in my car @ various times and never have i had it flood.

[SDEWY5]

hunting sounds like bov or vacuum leak (hole in something), will c ause it to foul plugs over time too

[Alkemist]

Unplugged the o2 Sensor. Car is running a hell of a lot better now. Idle is back to normal. Still something doesn't seem 100% right.

How would having no o2 sensor affect the operation of the car?

[mad082]

if the o2 was dicky it would be putting the mapping between open and closed loop mapping and instead of just altering the afr's between about 14 and 15 it would be between about 12 and 15. however i always thought that the o2 sensor was ignored at idle. as for how it will affect things otherwise, you can drive without an o2 sensor plugged in without any problems. you will just use a bit more fuel. just don't remove it then drive around.

and was said, your fuel pump shouldn't cause flooding as all it does is supply fuel, it doesn't have any real effect on how much is injected into the engine.

i would be looking at the AAC or IAC valves as they are the most common cause of hunting issues. o2 sensor can cause idle to fluctuate a small amount, but usually not hunting.