Gen II 3.5 Egoboost vac pump
 

I haven't found any info on the Gen II 3.5 after searching.
The only thing I know, is that the vac pump is now driven off the back of the right cylinder head. I realize it pulls a vac when the engine is under boost, for the brakes, IWE, etc.
Right now, and intermittently, it sounds like my left front IWE, is wanting to engage under light acceleration, sounds like a stone caught between rotor and dust shield. I can get it to stop by letting off the pedal, thereby increasing vac like on a NA engine.That's how I figured it's the IWE.
Yes, under warranty, just wanting info to educate myself and others.

I've been getting that sound too, usually happens when it is cold and the first start of the day.

Getting conflicting info about it being the wastegate for the driver side turbo or the IWE. Still need to get mine to the shop. I'd much rather it be the IWE than the turbo, lol.

here is a link to a video of my sound, let me know if its similar to yours?


J-

Yep yep, same sound. Happens just about the same times you're saying when still relatively cold,and light accelerating.
Most times a vacuum leak will cause that, but what puzzles me somewhat, why doesn't it do it all the time? Mine, I can feel thru the wheel as well, and today I felt and heard a dull thud from the front end just before coming to stop after coasting down from 60mph. Also, sometimes it feels like the right hub is locked, while the left isn't, when turning. I've had that happen on other trucks with the autolockers, and mine feels just like that. It'll sorta shimmy on you.

Yea I can feel mine through the floor/brake pedal. The timing has me stumped too. Only thing I can think of is that when cold, just starting out maybe there is a bigger need for vacuum in general by the engine systems but not enough to go around?

Also when mine does it its always seems to be while in fourth gear which seems like a bigger drop in RPM's than 1-2-3, maybe that starves the system since the pump is engine driven? Would also makes sense why it doesn't do it when acceleration is heavier.

Mine has never felt like it one or both of the hubs are locked, but its also never done it mid turn on me either.

I'm gonna see if I can get it to do it in the morning on the way home and try to shift into 4hi while its making the sound. Guessing if that it the issue the noise would stop or change.

J-

I tried shifting into 4Hi today, and it did quit, but it quits if I get entirely off the throttle as well. When shifting, it relies on loss of vac to pull in, and when taking your foot of the gas, the vac should increase, and pull the hub out. I asked about the pump, because normally, in an NA engine, the manifold vacuum is enough to do what's needed. I don't know if the vac pump is needed except when the boost kicks in. I have a boost gauge installed, and that was the first thing I looked at when the noise started, it showed zero boost. My gauge works thru the OBDII port, plus it's an nGuage, I "think" it should be fairly accurate.
Odd that both of us experience it thru the left hub.
I picked this truck up myself at another dealer as a trade, and drove it about 55 miles back to my dealer, with no problem. It had been sitting at the other dealer for a few weeks, and was stone cold when I took off with it. I'm gonna call my dealer in the AM and set up an appointment to have it looked at.

Oh, mine does it seems more in 10th gear.

Granted mine is a 2010 and not an ecoboost but, I had similar scenario. I replaced the solenoid and the check valve and it went away entirely.

Thanks, it wouldn't surprise me to be something simple like that. Was your noise on the left hub as well?

It actually went back and forth at times. Like I was adjusting the radio left and right balance from one extreme to the other. However, if I remember right it seemed to be coming from the middle and passenger side most of the the time.

LOL, Hubs in Stereo. Good song title.:D

:thumbup:

I don't really know if the check valve needed to be replaced. When I picked up the solenoid the SM wanted to install it. To help make up for the crap that the sales department pulled. While he was putting it on, he checked the valve and I asked if that would be the next thing to replace if it didn't go away. He then went and pulled one off a brand new F150 and put it on mine and mine on the new one. :eek: Not sure if I'd buy another vehicle from them but, the service department seems to be top notch.