Gen 2 Raptor Vacuum System

[brfails]

I have a 2018 Raptor, and I have been working for quite some time on the problem of intermittent grinding at the front driver-side wheel (IWE actuator). I have installed an entire new vacuum line from the solenoid to both wheels. I have used a vacuum pump with a gauge to test the new line, the actuators, the vacuum reserve reservoir, the solenoid, and the check valve. Today I tested the line coming from the Venturi???? device (not sure if I am even in the ballpark on that one), and the gauge on my vacuum pump was only showing 13 in Hg at idle. I realize I could just continue to drive around in 4A all the time but I have a problem in that I like things to work as they are designed. Any guidance on where to go next would very much be appreciated.

 

[New recaros]

What should the vacuum be?

 

[brfails]

I read that it should be 20-22 in hg

 

[New recaros]

I don’t see where you have checked the hub itself.

 

[Old-Raptor-guy]

I read that it should be 20-22 in hg

13 in hg seems a touch low, but you will never see 20-22 in Utah. Altitude affects vacuum (just like it affects compression readings). 17 in hg is what I normally see when testing engine vacuum, on a good engine. Out of curiosity I will check the vacuum on my 4x4 system later today. I am at approx 4700' above sea level.

Have you replaced the IWEs?

 

[fordfreek]

Pretty sure there's a vacuum pump involved also. Back of the passenger side cylinder head. If the IWE'S haven't been replaced and one or both are bad, they may have contaminated the system with dirt, depending on how much you've driven it since the line replacement. Dirt will ruin the check valve almost immediately. I tapped into the wheel side of the system at the solenoid and monitor the vacuum while driving. Usually does start to grind until vacuum is almost completely gone, like less than 5 inches

 

[Old-Raptor-guy]

Pretty sure there's a vacuum pump involved also. Back of the passenger side cylinder head. If the IWE'S haven't been replaced and one or both are bad, they may have contaminated the system with dirt, depending on how much you've driven it since the line replacement. Dirt will ruin the check valve almost immediately. I tapped into the wheel side of the system at the solenoid and monitor the vacuum while driving. Usually does start to grind until vacuum is almost completely gone, like less than 5 inches

I believe the vacuum pump has been deleted on 2017 +

 

[fordfreek]

I believe the vacuum pump has been deleted on 2017 +

I thought my 2020 had one, but I'm not 100% on that. I had issues with my system awhile ago. Been good for probably 18 months now. Mine ended up being an iwe that was bad, allowing dirt in the system which would contaminate the check valve almost immediately after I would change it. They ended up changing all the lines and both iwe's along with the check valve. I now have a vacuum gage hanging on my a pillar grab handle so I can monitor it all the time.
Know that it doesn't necessarily send vacuum to the iwe's at startup if you're in 2wd. Usually a couple miles before it applies vacuum. Seems to take longer the colder it is outside.

 

[brfails]

13 in hg seems a touch low, but you will never see 20-22 in Utah. Altitude affects vacuum (just like it affects compression readings). 17 in hg is what I normally see when testing engine vacuum, on a good engine. Out of curiosity I will check the vacuum on my 4x4 system later today. I am at approx 4700' above sea level.

Have you replaced the IWEs?

Thank you for your response and assistance. I did replace the IWE’s.

 

[Old-Raptor-guy]

I thought my 2020 had one, but I'm not 100% on that. I had issues with my system awhile ago. Been good for probably 18 months now. Mine ended up being an iwe that was bad, allowing dirt in the system which would contaminate the check valve almost immediately after I would change it. They ended up changing all the lines and both iwe's along with the check valve. I now have a vacuum gage hanging on my a pillar grab handle so I can monitor it all the time.
Know that it doesn't necessarily send vacuum to the iwe's at startup if you're in 2wd. Usually a couple miles before it applies vacuum. Seems to take longer the colder it is outside.

I posted in another IWE thread the proper vacuum strategy.

Short version.

Above 32, hubs stay engaged (no vacuum) for 1/2 mile after start

Below 32, it is 1 or 2 miles. This is to warm up the front differential.