My 2001's (2.0 Zetec) fuel pump has started making a loud buzzing noise in the last few days. Truck has about 118k miles on it (don't know if it's the original pump). Sometimes it will buzz constantly and other times it will switch back and forth between the normal high pitched whine and buzzing.

I put my ear up to the gas tank and it's definitely coming from there. I can even feel the tank buzzing if I put my hand on the tank skid plate. The vibration matches with the sound when it's switching between the whine and buzzing.

No driveability, starting, or other problems but since it's my daughter's truck I don't want the pump to die while she is driving (I have had this happen to me a few times and it can be dangerous).

With that said, at around $200 this is not a part I can replace on a whim "just in case." So I come here to ask if anyone else thinks this may be a symptom of the pump going out or if it's just a "normal" aging pump or other problem? I have had fuel pumps make all sorts of sound for years without issues. Thoughts?

 

Ever hear of current ramping? You connect a current clamp probe to either the power feed or pump ground wire and look at the waveform on a scope. You'd be able to see most any type of problems.

 

I've personally had noisy pumps last for years. Not to say yours will last like it is, but sometimes even a new pump will be a little noisier than the original pump. You might end up changing it, and it still makes noise.

There is a rubber insulator that is usually wrapped around the pump to help muffle noise, maybe it slipped off, you never know.

 

In my experience with electric fuel pumps I have never had one decide it wanted to buzz rather than hum. Trying to imagine what is going on inside that can cause vibration, makes me think that either the armature bearings are going out or the impeller, whatever the shape or design, is destructing. What moves? The armature and impeller. If the bearings or bushings are going out, that would allow the armature to wobble more than normal, causing vibration. If the impeller were damaged {how??, unless parts broke off}, it would have to be either coming loose on the armature or missing blades of some sort.
I am not sure about this setup but it used to be that you could buy an aftermarket pump only for a lot less than the sender unit, which is the whole assembly that drops into the top of the tank. I would check with aftermarket sources for just the pump alone, and expect the cost to be about 1/4 of the complete sender. If your fuel gauge has intermittent readings, and you want it to work, you would have to replace the complete assembly.
I have read that worn pumps will draw more current than healthy ones. That was what I thought was a current draw 'ramp', where the startup current was x.x and the final, running at speed current was y.y, and you could watch the draw change. But, I don't do this for a living...
tom

 

TomW:

Here's a link for current ramping a fuel pump: current_ramping.

Older vehicles had a test or fuel pump test lead connector in the engine compartment, you just power it with a +12V to run the pump and connet a current probe there. No such thing on newer vehicles.

Finding current specs is the trick! Fuel pump access on the Escape is easy, it's under the rear driver's side seat, under the carpet cutout.

 

Yeah, I don't think I'm going to have access to the equipment necessary to do current probing.

I'd like to test the fuel pressure but it's a PITA on the 4-cyl because there is no Schrader valve. I'm not sure if that would show anything anyway since it's running normally.

Looking at sourcing fuel pumps has been daunting. Airtex is the only thing locally available and there seems to be an incredible amount of failures with those pumps (although maybe not an issue with the Zetec's lower 40 PSI). Everything else is special order or mail order and very expensive. All this for a pump that I don't even know is failing or not.

 

I have videos by Jim Linder of Linder Tech(fuel injector service). In one he states, it's not if a fuel pump will fail, it's when, it's a given. At 118K...........

 

But the trick is to know if it's about to let go or can last for years.

If I definitely knew it was the original pump then I would be leaning strongly towards replacing it now. Probably impossible to know unless there is an aftermarket pump in there. I guess I should take it out and see.

 

The pumps are super easy to change.I bought a new one from Ford for $280.00.The original pump had 180,000 when it failed.

 

This is normally an indication of imminent failure.

 

If it's not failing, why did it start making noise now? Thicker fuel? More water causing the bearings to heat up? (The pump is lubricated and cooled by the fuel.)Plugged filter causing it to have to work harder?
I think it would be worth it to remove & inspect closely. Not difficult, but you have to be careful to have good ventilation with the tank open, and don't cause sparks when removing or installing the sender.
tom

 

To remove pump
flip up driver side back seat there is a cut out in the carpet.locate the plate remove two phillips screws.There it is 2 lines and 2or 3 plugs.I took a piece of wood and a hammer and tapped the nut loose then spun it off.

 

Oh I know the pump is easy to replace. It's the cost that's making me pause. The price seems a little ridiculous to me considering even a BMW's fuel pump is cheaper.

No point spending all that money if it ain't going out. But the consensus seems to be that it's about to fail. I miss the old mechanical pumps that just starting leaking fuel all over the place (but still kept working) when they failed.

 

Well, I remember the combo vacuum/gas fuel pumps. The 1" hose sections connecting the pump to the 'hard lines' got oiled by the leaking rocker arm covers, or the timing chain gasket or even the crankshaft seal... and then you had no wipers going up hill... When the diaphragm broke, they'd squirt fuel out the little vent hole right onto the drivers side fender liner. Great.
Seems you could get a kit of parts to repair them, until the last units fitted, as they were held together with actual screws. Was a pain to compress the spring... Cost about 1/3 of an electric, and repair kits were 1/2 of that. But, we're talking quite a while ago.
I poked around one parts place, and they had pumps, generic and 'exact fit', and fuel sender assemblies. The exact fit pumps were in the $107-131 range, and senders were $219-312 for non-OEM brands. If it were me, I'd get a new pump. A tow bill will be more than that... A hospital visit ... Let's not go there.
You could say it cost you ~$1 per 1000 miles driven, which isn't so bad.
tom