2001 7.3 momentary whine prior to start from engine compartment what is it?

[farsrr]

Have had this 2001 Powerstroke since new. No real problems. Buddies truck started this high pitched whine when you turn the key on and then goes away pretty quickly. Mine started it today. They both only do it intermittently and we have no performance loss. This all happens prior to start and only whines for approx. 5 seconds.
What do ya'll think?
Whine comes from under the hood.
Thanks,
Andy

[Dietoremain]

Vacuum pump? They can get noisy when they get old.. lol

[Super Diesel]

Are you talking like a belt squeal kinda whine? Or something different?

[farsrr]

Key on but the engine is not turning. As soon as you turn the key to lets say accessory position a buzzing/whine sound comes for the engine compartment. It stays on for approx 5 seconds and then goes off. It may be more of a squealing whine than a buzz be its hard to explain in text.
Thanks,
Andy

[Super Diesel]

Originally Posted by farsrr

Key on but the engine is not turning. As soon as you turn the key to lets say accessory position a buzzing/whine sound comes for the engine compartment. It stays on for approx 5 seconds and then goes off. It may be more of a squealing whine than a buzz be its hard to explain in text.
Thanks,
Andy

Okay... this is gonna sound dumb, but are you talking about the glow plugs? If so, that sound is normal. Its the glow plugs warming up.

[farsrr]

Glow plugs making a whining / sqealing sound? I'm afraid Ive never heard that. I did find a TSB that mentions a whining or buzz and refers to a fuel regulator. I will do some research on both.
Thanks,
Andy

[DieselSVT]

Mine does it too. I've always attributed it to the fuel flowing through the filter/regulator assy when the pump kicks on.

Is there a plan of action for the TSB or does it say its a charecterisitc of the vehicle?

[farsrr]

The TSB is 98-17-16. It states that some may experience a buzzing noise from the fuel pressure regulator with key on engine off during fuel pemp cycling. It is caused by low fuel pressure due to the fuel pressure regulator seal (o-ring) splitting.
The Action is to replace the fuel pressure regulator with a revised Fuel pressure regulator valve part number (F81Z-9B249-BB). But I was not sure of the exact location of that regulator and have not put my finger on the location of the noise on my truck because it doesnt do it all the time. Was just hoping some other guys may have experienced this so we could get to the bottom of it. I figured since my buddies truck does it and then mine started, must be a common issue.
Thanks for the reply,
Andy

[Super Diesel]

Oh... this is my first diesel and both mine and my roommate's diesel did this. I was told that it was the glow plugs and took their word for it. I guess I'll have to do some digging myself. The noise coming from the fuel pressure regulator would make more sense...