w_hari

Hi Folks.

Was a hell of a weekend. Spent 20 hours changing my clutch + installing a RB header. Well, finally everything runs fine but I noticed one thing. When I turn my key in the position ON (not starting the engine) I heard a buzzing sound from the back of my car and under the hood I can hear something flowing (which seems to come from the secondary fuel lines). So I assume the fuel pump is already running but it shurely didnt do this before!?!

greetings,

Harry

PS: The pilotbearing was a hell of a job. Was already destroyed and the needles just laying inside the shaft. Had no remover anyway so I did it with a chisel (was like welded in).

Syonyk

Yea, that's the fuel pump running, all right.

There's a yellow 2-prong female connector on the passenger's side of the engine bay, up near the air filter. If this is jumpered, it'll run the fuel pump. Any chance you managed to jumper this somehow while working on stuff? Or alternately, if the wires to this shorted somewhere, it would do the same thing, and you were working on that side of the engine for the exhaust.

That's not normal, for sure. However, I don't really think it will hurt anything. I'm not sure what the duty cycle of the pump is under normal running, but I suspect it spends most of it's time on during highway & faster driving.

-=Russ=-

w_hari

I know the yellow connector and it was the first thing I checked - wasnt jumpered. But I will check if the wire is shorted anywhere else (good idea). Just am scared that it will build up too much preasure and will cause some fuel lines to burst!

Harry

Tofuball

I was under the impression that the fuel pump was supposed to run when the key was to the ON position

w_hari

Well, yes it is supposed to run when the key is in the on-position AND the engine is running. But not if you just turn the key to on!

Syonyk

Oh. Regarding fuel pressure, if the fuel pump can build up enough pressure to burst a fuel line, your fuel lines were really bad to begin with. The way the system works is that the fuel pump provides a lot of fuel, and the pressure regulator at the end of the secondary fuel rail maintains pressure in the fuel rails, venting excess fuel back to the tank. This leads to always having cool fuel in the rails. The procedure to get fuel back into the engine after a filter change or rebuild or such is to run the fuel pump for a while with the jumper - nothing bad happens there (or if something bad does happen, you didn't put things together properly).

I've heard rumors that the TII fuel pump at the full 12v setting can overwhelm the fuel pressure regulator at idle (and probably with the engine off), which is why it has the dropping resistor pack for low RPM. Can anyone confirm this? I have TII pump I was considering swapping into my NA.

Honestly, I wouldn't worry too much about the fuel pump running with the key on. Obviously something has changed, and I'd look for shorted or pinched wires, but I don't think it will cause any serious problems.

Plus, how long do you really leave the key in the on position without the engine running? I usually get in, press the brake & clutch, and start the car.

-=Russ=-

fdannels

I went from a stock fuel pump at 19 psi, to a Walboro pump at 90pci. Do I need to adjust the fuel pressure regulator, or the A/F mixture screw on top of the intake?