2010 Escape weirdest noise EVER

[Mekanik]

I have a 2010 Escape with a V6 that I’m working on. It sounds like an engine noise that occurs on light accel from a stop when the engine is really warm. I can also get it to happen in park around 1300RPM and around 1700RPM. It is a very hard noise to duplicate, and even harder to recreate so it happens consistently. I can hear it in the passenger compartment, not at all in the engine compartment or when I'm under the vehicle. This makes it VERY difficult to diagnose.

 

It seemed like the rear cam phaser was louder than the front, and I felt that it reminded me of a 5.4L phaser that was noisy. Well the phaser didn't fix it. Two hours later I notice something very peculiar. When I can get the noise to happen, as soon as I step on the brake pedal the noise stops. I take my foot off the brake pedal, keeping the RPM at the same speed and the noise comes back. It's funny the way it starts because it sounds like it starts slowly and then builds up. Yeah, I've spent a lot of time on this truck and I'm really tuned into it by now.

 

I've got a brake booster ordered for tomorrow. I think that the diaphragm inside the booster is loose and rattling around when it gets just the right amount of vacuum applied to it. In eighteen years I have NEVER replaced a booster for a noise that sounds like it's coming from the engine.

[Jim Warman]

Have you run the car with the FEAD belt off?

[Mbl35]

intake manifold related, possibly a concern with the imrc??

[Mekanik]

Jim-No, I listened to the tensioner and accessories when the noise happening and couldn't hear anything abnormal.

 

MBL35-I think the RPM is too low for IMRC, but that’s an interesting theory. I’m not even sure if it has an IMRC.

 

The booster did not fix the concern. The next thing I did was swap the check valve for the booster from an Explorer. That changed the noise making it a lower pitch, and also harder to get to happen. I think it almost made it acceptable. Next I swapped the valve from another 2010 Escape and the noise sounded the same, but also was less frequent. When I put the original valve back in, there is a night and day difference. My service director even agreed that it is easier to produce and a higher pitch and more of a tinny noise (with the original check valve).

 

When I unplug the vacuum line to the booster the noise is completely gone. My service director is going to drive another 2010 Escape and listen for the noise this afternoon (I'll be dressed as Abraham Lincoln at my 1st grader's school Halloween Party). I never tried to get the noise to happen in a similar vehicle because it is so hard to produce, but that is where I’m at right now with this truck. I really think the noise is coming from the brake booster because I hear it more on the driver’s side, and applying the brakes and removing the vacuum line (with it plugged) eliminates it.

[Mbl35]

Oh, i think the 09 have a butterfly valve in the plenum