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Fuel pump whistles

When I turn my key on (but don't crank the engine), I get a 5-second whistling noise from my fuel pump. (At least that's what I assume the noise is coming from, it's in the right area and I don't know what else might make the noise). The noise resumes when the engine starts (but is mostly drowned out by the engine/exhaust noise). It sounds kind of like the noise a CRT TV makes when it's on but the volume is muted. Is this normal? I have a 1988 Nissan Cefiro turbo.

Also, my engine stopped misfiring when I filled my tank full, and started again when the tank got back to near empty. (Most of the time I drive around with it near empty). Is this possible, or am I just imagining things? The misfiring occurs only at WOT or heavy throttle usage, at full boost.

Reply to
Old Wolf
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Fuel pumps are liquid cooled. When you continuously drive around low on fuel the fuel pump overheats and the life expectancy is reduced. From the symptoms you describe I would guess that you are going to be in for a pump replacement soon.

Steve B.

Reply to
Steve B.

Heats but not overheat. The fuel pump has a built in relief valve, fluid would continuously recalculate at any level.

Reply to
Ricky spartacus

"Ricky spartacus" wrote

"Circulate."

Reply to
Ricky spartacus

Ive seen this happen when the fuel tank was rather habitually run low. And in this case, a fuel pump failure did follow suit. If the pump is not immersed in the gasoline, I would suspect you lose some cooling capacity just as Steve suggested.

Habitually running your tank low is just not the wisest of practices. Winter has a way of promoting problems we didnt worry about in the summer.

Reply to
<HLS

Yes, it is normal for the fuel pump tp pressurize the system before you start the car.

You my have a fuel pickup issue.

---------------- Alex

Reply to
Alex Rodriguez

Yes it would if there were fluid there to circulate which is why you need to not run the tank low on gas. When you are very low on gas the pump can suck air and overheat.

Steve B.

Reply to
Steve B.

On a vehicle that won't shut off when it begins to suck in air that is when it becomes destructive. However, based on most fuel injection designs, any air being sucked up will immediately shut off the vehicle and the pump. If the vehicle stalled from this then this is considered neglect.

I ran a tested on a functional Honda pump and circulated some fuel thru a long hose using a car battery. I notice that the pump didn't over heat, but in fact ran very cool. But when I ran without fuel, the unit seizes in no time (less than 5 seconds.) The bearings is fine but the propellers (correct term?) is destroyed from heat.

Reply to
Ricky Spartacus

On pumps I think they are called "impellers", at least that's what they're called on water pumps.

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