I guess EVO's don't like the cold weather. I have BR S4 setup and just dynoflash last weekend. I went to start the car today since Saturday and now I hear a noise. The noise seems to be coming from the back so I think it's the walboro fuel pump but just wanted to ask and make sure. The noise sounds like a siren kinda like static radio noise (radio not on). If I press the window or lock/unlock switch my battery drops down to 12V and noise changes pitch with the drop in battery voltage.

Is my TC or walboro fuell pump about to GO or is it normal noise of the walboro in the cold weather?

If someone can give me some assurance that would be great.

Thanks.

 

tc whats that get a fuel pupm anyway 80 bucks cant go wrong

 

My fuel pump makes a lot of noise sounds like a high pitch whine. Mine does it in hot weather though. I cant really vouch for cold weather. I dont really remember what cold feels like anymore.

 

I don't know, but if I put an electrical load on the car such as the power window, it changes the sound of the fuel pump like it's drawing power from it. That's only when I hear the pump and now that it's cold, I do not hear it, unlike the hot summer days.

 

My Walbro pump used to do that on a DSM I owned. I measured a voltage fluctuation at the pump...even the turn signal used to cause it to fluctuate. To fix it I bought a basic car audio amplifier kit and used it to provide power to the pump, where the OEM power line acted as the trigger for the relay. This fixed the problem, giving me steady voltage at the pump.

Have you checked your connections? If it didn't do it at first or only does it sometimes, then I'd suspect there is a loose electrical connection somewhere.

 

My pump has been whining for several months now also, kinda a high pitched sound that is most audible on drivers side rear of the car. Hasn't hampered performance at all

 

Thanks for the help. It sounds like the fuel pump is causing the noise. I never had that noise in the summer and it just started when the weather got cold. It was okay the otehr day until yesterday when it was more pronounce. I'll check for loose connection this weekend and maybe change it out.

This is some information I got from evomoto.com

'A few tidbits about the Evo fuel pump/tank:

There are TWO fuel level senders, one for each side of the saddle-type fuel tank.
The fuel pump gets fuel itself directly from its side of the tank, as well as the opposite chamber via a "suction hose".
The fuel pump is relay powered directly from the battery. Modded DSM owners probably know why this is important and is not a mod that needs to be done on the Evo (yeah!) If you have no idea of the implication of how indirect power supply and the resulting voltage drop effect fuel pump output, you should do a web search, but here's a hint: 15%-20% flow change between 12V and 14V!
The fuel pump operates in 2 modes: high and low. Depending on engine state and fuel consumption requirements (all determined by the ECU), the pump either gets full voltage (13.5-14.4V obviously) for added flow, or lower voltage to reduce flow, reduce pump noise, and reduce fuel vapor discharge. The high/low power path to the fuel pump either goes through the mysterious "Fuel Pump Relay 3" (full voltage) or through the "Fuel Pump Resistor" (low voltage).
Tank capacity: 14 gallons
'

 

Normal sound for the Walbro.

 

If the fuel pump goes while I'm driving will my engine grenade??

 

My Walbro also whines loudly when it is cold. Also, I can hear the voltage drop on the pump when I use my windows, turn on the vents or when the radiator fan kicks on