Hi Folks,

I heard a very strange noise on my 2001 F150 5.4 L 4WD:


Since it occurred after 2 seconds or so after turning the key to ON position but without start, about the same time of the forth chime, so I never noticed this sound before until one day I wished to test all warning lights on the dash. It was like coming from somewhere underneath the hood at driver side, and when it sounded I could slightly feel kind of a bit of vibration like something sinking to bottom ....What could it be? Maybe the fuel pump?

Any suggestion will be appreciated.

 

I don't hear anything.

It's probably your fuel pump priming.

 

The sound is coming at the same time of the forth chime "dang..dang..dang.. dang", because it was from outside of the cabin so it did not sound as loud as the chime. I guessed it was the fuel pump priming too but it was not like the priming sound from some other vehicles I was familiar with.

 

When was the last time you changed the fuel filter?

Get someone to help you. Get outside the truck and have someone else turn the key on, try to find exactly where the noise is coming from. If it's in the area of the fuel tank, it's the fuel pump.

 

I bought this truck used and I have not replaced the fuel filter since. I have no idea how old it has been, it looks kinda rusted outside but I have not felt any fuel problem.

 

Change it. If it looks rusty it's overdue, it should be changed every 50,000 km.

 

I heard the noise and I agree, it is weird. See if you can do what glc said and get someone else to turn the key while you try to identify the source.

 

yes I will have someone sit inside the cab to turn key and I listen outside to identify the source. thank you.

 

I agree that I should change it. I will try to get a chance to change but am not sure that will happen in winter. Other than the weird sound, the truck runs just fine though, engine sounds nice, mpg is not bad, no any warning light at all, shifts fine, powerful when towing.....I will update if I have it done. Thanks anyway.

 

The noise sounds like from somewhere around the brake paddle or booster. It is absolutely not from the fuel tank. It is closer to the front.

 

Open the hood and use a length of heater hose as a stethoscope to try to localize it. Check around the brake booster, the evap purge valve is right next to it.

 

I have located the source of the noise, it was from the abs module. I have someone turn the key inside the cab, and I held the abs module, I guess it was, the one under the MAS housing and the brake cylinder, and with a couple of brake lines in and out, and I could feel the vibration on it when the sound was coming. It sounded like a motor activated and then stopped inside, I guessed it was how the system tested the module. So far there is no ABS warning light on the dash, and the brake works just fine. I am not quite familiar with how abs module works, but could this sound suggest anything getting worn?

 

I don't know if the noise is normal, but it makes sense that it will do something when powering up. If it does fail, replacements aren't particularly cheap:

https://www.rockauto.com/en/catalog/...ol+module,1844

 

I have located the source of the noise, it was from the abs module. I have someone turn the key inside the cab, and I held the abs module, I guess it was, the one under the MAS housing and the brake cylinder, and with a couple of brake lines in and out, and I could feel the vibration on it when the sound was coming. It sounded like a motor activated and then stopped inside, I guessed it was how the system tested the module. So far there is no ABS warning light on the dash, and the brake works just fine. I am not quite familiar with how abs module works, but could this sound suggest anything getting worn?

I can see that you have got similar truck as mine, would you mind doing the same test as what I did to see what happens to your ABS module or maybe called ABS ECU?

 

I don't have a helper but I went out and opened the hood, turned the key on and after a couple of seconds I did hear a noise that came from the area you are talking about. It's not as loud as your noise and doesn't sound exactly the same but I do have a similar noise. I never noticed it before and it isn't audible from inside the cab.