Originally Posted by David Hineline

If the vacuum holds at 18 with no leakdown that system should work fine. you can put a tee connection on the output of the solenoid and sneak a hose out of the hood, connect it to the above gauge tape the gauge to the windshield and drive around and see how the vacuum levels are as you drive and when the noise happens. Turbo engines have poor vacuum levels the harder you accelerate and best vacuum levels at idle. That is the purpose of the check valve and the vacuum tank, to hold/maintain the best vacuum levels in the reservoir and stop leakback from the reservoir when engine vacuum is lowest. My original damage was due to leakback by failed checkvalve complicated by my poor hearing until it was too late and the grinding had eaten the IWE ring and the splines on the hubs so both had to be replaced. I put two of the new style blue/white Ford check valves in series on the supply line to help prevent the issue in case of future failure of one checkvalve.

Originally Posted by David Hineline

There is no vacuum pump for this, the vacuum pump on the ecoboost engine is just for the power brake assist, the IWE system just runs off crankcase vacuum. Crank case vacuum varies and lowers the harder you open the butterflies in the throttle body, the harder you accelerate the butterflies open and reduce crankcase vacuum. The PCV positive crankcase valve super easy to change out and cheap, the one way ball in that can stick and leak screwing up crank case vacuum. Some have reported that a hose coming off the crankcase and going into a tee towards the check valve can with time collapse and cause a choke point restricting vacuum, Pull your check valve and blow through it, air should only go one way with no leaks. Dropping to zero should only happen normally when the solenoid closes and blocks the vacuum to the IWEs, when it closes it vents the IWE lines to outside air and vacuum to the IWEs drop instantly. A bad intermittant connection to the solenoid could cause a rapid drop in vacuum. Put your gauge again with an auto parts tee fitting on the input line to the solenoid and see if the vacuum drops there. If vacuum drops there you have a problem before the solenoid, if vacuum stays strong there and still having issues then electrical command to or the solenoid is failing or a line from the solenoid going to either IWE is venting to outside air.

Originally Posted by David Hineline

There is no vacuum pump for this, the vacuum pump on the ecoboost engine is just for the power brake assist, the IWE system just runs off crankcase vacuum. Crank case vacuum varies and lowers the harder you open the butterflies in the throttle body, the harder you accelerate the butterflies open and reduce crankcase vacuum. The PCV positive crankcase valve super easy to change out and cheap, the one way ball in that can stick and leak screwing up crank case vacuum. Some have reported that a hose coming off the crankcase and going into a tee towards the check valve can with time collapse and cause a choke point restricting vacuum, Pull your check valve and blow through it, air should only go one way with no leaks. Dropping to zero should only happen normally when the solenoid closes and blocks the vacuum to the IWEs, when it closes it vents the IWE lines to outside air and vacuum to the IWEs drop instantly. A bad intermittant connection to the solenoid could cause a rapid drop in vacuum. Put your gauge again with an auto parts tee fitting on the input line to the solenoid and see if the vacuum drops there. If vacuum drops there you have a problem before the solenoid, if vacuum stays strong there and still having issues then electrical command to or the solenoid is failing or a line from the solenoid going to either IWE is venting to outside air.

Originally Posted by David Hineline

So when the ground signal was applied to one side of the solenoid coil and you say the solenoid works, did you pull the hose off the output of the solenoid to see if you have suction there? Just because a solenoid is energized does not mean it has suction going in and or passing the suction going out. A solenoid uses a coil of wire to create a magnetic field to control a plunger valve to pass or block air flow. Solenoids activate with electrical current flow. So with a good ground signal applied to one end of the solenoid coil a piece of wire is all a coil is, if there is no current flow both ends of the solenoid coil, just a piece of coiled wire, you will measure no voltage across it. The hot side of the solenoid coil is connected to a constant source voltage, when the ground is removed from the actuation signal, the hot side will float up to what ever voltage the source is because there is no current flow to drag the source down. So it will read what ever voltage the source is connected to. Once the solenoid control lead is shorted to ground by the control module, if the wiring to the source or a connection to the source has gone resistive it will be dragged down and the voltage will be dropped by the resistance of the source wire and no voltage drop is across the solenoid coil and no current is flowing. At idle the ecoboost produces it's max vacuum, your vacuum gauge going into the check valve should be 20 inches, out of the check valve should be 20 inches, into the vacuum reservoir 20", out of the reservoir 20" into the solenoid 20" out of the solenoid 20" at the vacuum line to each IWE 20". Now if all of that is good, check the IWE vent lines. A vacuum IWE diaphragm can not actuate if it's vent line is plugged to outside air. If all that is OK mechanically the diaphragm can tear loose from the actual IWE gear, alo allowing it to grind too much for too long can take off the engagement splines off the drive hubs causing slippage. Another common issue is the monkey who installed new factory greased IWEs thought that's not enough grease and added more grease because more grease has to be more better. This usually shows up in cold weather when more better grease gets thick and won't like the IWE ring gear slide freely.

Originally Posted by johnday in BFE

Guys, try this TSB, https://www.google.com/url?sa=t&sour...66o8zRp9PE11AH

Originally Posted by dantekub

Not happening.

Originally Posted by johnday in BFE

What, you can't pull it up, or you won't do the TSB?
TSB 20-2028 in case you can't pull it up.